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Papers for Tuesday, May 21 2024

Papers with local authors

Stellar convection poses two main gargantuan challenges for astrophysical fluid solvers: low-Mach number flows and minuscule perturbations over steeply stratified hydrostatic equilibria. Most methods exhibit excessive numerical diffusion and are unable to capture the correct solution due to large truncation errors. In this paper, we analyze the performance of the Spectral Difference (SD) method under these extreme conditions using an arbitrarily high-order shock capturing scheme with a posteriori limiting. We include both a modification to the HLLC Riemann solver adapted to low Mach number flows (L-HLLC) and a well-balanced scheme to properly evolve perturbations over steep equilibrium solutions. We evaluate the performance of our method using a series of test tailored specifically for stellar convection. We observe that our high-order SD method is capable of dealing with very subsonic flows without necessarily using the modified Riemann solver. We find however that the well-balanced framework is unavoidable if one wants to capture accurately small amplitude convective and acoustic modes. Analyzing the temporal and spatial evolution of the turbulent kinetic energy, we show that our fourth-order SD scheme seems to emerge as an optimal variant to solve this difficult numerical problem.

Anavi Uppal, Charlotte Ward, Suvi Gezari, Priyamvada Natarajan, Nianyi Chen, Patrick LaChance, Tiziana Di Matteo
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Paper 8 — arXiv:2405.11026
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Paper 8 — arXiv:2405.11026

Supermassive black holes (SMBHs) can be ejected from their galactic centers due to gravitational wave recoil or the slingshot mechanism following a galaxy merger. If an ejected SMBH retains its inner accretion disk, it may be visible as an off-nuclear active galactic nucleus (AGN). At present, only a handful of offset AGNs that are recoil or slingshot candidates have been found, and none have been robustly confirmed. Compiling a large sample of runaway SMBHs would enable us to constrain the mass and spin evolution of binary SMBHs and study feedback effects of displaced AGNs. We adapt the method of varstrometry -- which was developed for Gaia observations to identify off-center, dual, and lensed AGNs -- in order to quickly identify off-nuclear AGNs in optical survey data by looking for an excess of blue versus red astrometric jitter. We apply this to the Pan-STARRS1 3pi Survey and report on five new runaway AGN candidates. We focus on ZTF18aajyzfv: a luminous quasar offset by 6.7 ± 0.2 kpc from an adjacent galaxy at z=0.224, and conclude after Keck LRIS spectroscopy and comparison to ASTRID simulation analogs that it is likely a dual AGN. This selection method can be easily adapted to work with data from the soon-to-be commissioned Vera C. Rubin Telescope Legacy Survey of Space and Time (LSST). LSST will have a higher cadence and deeper magnitude limit than Pan-STARRS1, and should permit detection of many more runaway SMBH candidates.

Minghao Guo, James M. Stone, Eliot Quataert, Chang-Goo Kim
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Paper 50 — arXiv:2405.11711
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Paper 50 — arXiv:2405.11711

We present three-dimensional magnetohydrodynamic (MHD) simulations of the fueling of supermassive black holes in elliptical galaxies from a turbulent cooling medium on galactic scales, taking M87* as a typical case. We find that the mass accretion rate is increased by a factor of 10 compared with analogous hydrodynamic simulations. The scaling of ˙Mr1/2 roughly holds from 10pc to 103pc (10rg) with the accretion rate through the event horizon being 102Myr1. The accretion flow on scales 0.033kpc takes the form of magnetized filaments. Within 30pc, the cold gas circularizes, forming a highly magnetized (β103) thick disk supported by a primarily toroidal magnetic field. The cold disk is truncated and transitions to a turbulent hot accretion flow at 0.3pc (103rg). There are strong outflows towards the poles driven by the magnetic field. The outflow energy flux increases with smaller accretor size, reaching 3×1043ergs1 for rin=8rg; this corresponds to a nearly constant energy feedback efficiency of η0.050.1 independent of accretor size. The feedback energy is enough to balance the total cooling of the M87/Virgo hot halo out to 50 kpc. The accreted magnetic flux at small radii is similar to that in magnetically arrested disk models, consistent with the formation of a powerful jet on horizon scales in M87. Our results motivate a subgrid model for accretion in lower-resolution simulations in which the hot gas accretion rate is suppressed relative to the Bondi rate by (10rg/rB)1/2.

Yueyue Jiang, Jing Zhong, Songmei Qin, Tong Tang, Li Chen, Jinliang Hou
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Paper 57 — arXiv:2405.11853
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Paper 57 — arXiv:2405.11853

We investigated the stellar mass function and the binary fraction of 114 nearby open clusters (OCs) using the high-precision photometric data from Gaia Data Release 3 (Gaia DR3). We estimated the mass of member stars by using a ridge line (RL) that is better in line with the observed color-magnitude diagram (CMD), thus obtaining more accurate stellar mass and binary mass ratio (q) at the low-mass region. By analyzing the present-day mass function (PDMF) of star clusters, we found that 108 OCs follow a two-stage power-law distribution, whereas 6 OCs present a single power-law PDMF. Subsequently, we fitted the high(low)-mass index of PDMF (dN/dmmα), denoted as αh(αl), and segmentation point mc. For our cluster sample, the median values of αh and αl are 2.65 and 0.95, respectively, which are approximately consistent with the initial mass function (IMF) results provided by Kroupa (2001). We utilized the cumulative radial number distribution of stars with different masses to quantify the degree of mass segregation. We found a significant positive correlation between the state of dynamical evolution and mass segregation in OCs. We also estimated the fraction of binary stars with q0.5, ranging from 6% to 34% with a median of 17%. Finally, we provided a catalog of 114 nearby cluster properties, including the total mass, the binary fraction, the PDMF, and the dynamical state.

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Wei Hu, Pei Li, Arno Rogg, Alexander Schepelmann, Colin Creager, Samuel Chandler, Ken Kamrin, Dan Negrut

Recently, there has been a surge of international interest in extraterrestrial exploration targeting the Moon, Mars, the moons of Mars, and various asteroids. This contribution discusses how current state-of-the-art Earth-based testing for designing rovers and landers for these missions currently leads to overly optimistic conclusions about the behavior of these devices upon deployment on the targeted celestial bodies. The key misconception is that gravitational offset is necessary during the \textit{terramechanics} testing of rover and lander prototypes on Earth. The body of evidence supporting our argument is tied to a small number of studies conducted during parabolic flights and insights derived from newly revised scaling laws. We argue that what has prevented the community from fully diagnosing the problem at hand is the absence of effective physics-based models capable of simulating terramechanics under low gravity conditions. We developed such a physics-based simulator and utilized it to gauge the mobility of early prototypes of the Volatiles Investigating Polar Exploration Rover (VIPER), which is slated to depart for the Moon in November 2024. This contribution discusses the results generated by this simulator, how they correlate with physical test results from the NASA-Glenn SLOPE lab, and the fallacy of the gravitational offset in rover and lander testing. The simulator developed is open sourced and made publicly available for unfettered use; it can support principled studies that extend beyond trafficability analysis to provide insights into in-situ resource utilization activities, e.g., digging, bulldozing, and berming in low gravity.

We construct explicit models of classical primordial standard clocks in an alternative to inflation, namely the slowly contracting ekpyrotic scenario. We study the phenomenology of massive spectator fields added to a state-of-the-art ekpyrotic model, with coupling functions that allow for these heavy fields to be classically excited while the background is slowly contracting. We perform numerical computations of the corrections to the scalar primordial power spectrum and compare with analytical estimates. Our full numerical results reveal so-called clock signals, sharp feature signals, as well as signals that link the two together. The models are found to predict oscillatory features that are resolutely different from what is calculated in inflation, and thus, such features represent unique fingerprints of a slowly contracting universe. This confirms the capability of primordial standard clocks to model-independently discriminate among very early universe scenarios.

Yayaati Chachan, Paul A. Dalba, Daniel P. Thorngren, Stephen R. Kane, Eve J. Lee, Edward W. Schwieterman, Howard Isaacson, Andrew W. Howard, Matthew J. Payne

Systems hosting multiple giant planets are important laboratories for understanding planetary formation and migration processes. We present a nearly decade-long Doppler spectroscopy campaign from the Keck-I telescope to characterize the two transiting giant planets orbiting Kepler-511 on orbits of 27 days and 297 days. The radial velocity measurements yield precise masses for both planets, which we use to infer their bulk heavy element content. Both planets contain approximately 30 Earth masses of heavy elements, but their bulk metallicities (i.e., the ratio between metal mass and total mass) are drastically different (0.86±0.04 and 0.22±0.04 respectively). Envelope mass loss cannot account for this difference due to the relatively large orbital distance and mass of the inner planet. We conclude that the outer planet underwent runaway gas accretion while the inner planet did not. This bifurcation in accretion histories is likely a result of the accretion of gas with very different metallicities by the two planets or the late formation of the inner planet from a merger of sub-Neptunes. Kepler-511 uniquely demonstrates how giant planet formation can produce strikingly different outcomes even for planets in the same system.

Luis Welbanks, Taylor J. Bell, Thomas G. Beatty, Michael R. Line, Kazumasa Ohno, Jonathan J. Fortney, Everett Schlawin, Thomas P. Greene, Emily Rauscher, Peter McGill, Matthew Murphy, Vivien Parmentier, Yao Tang, Isaac Edelman, Sagnick Mukherjee, Lindsey S. Wiser, Pierre-Olivier Lagage, Achrène Dyrek, Kenneth E. Arnold

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Interactions between exoplanetary atmospheres and internal properties have long been hypothesized to be drivers of the inflation mechanisms of gaseous planets and apparent atmospheric chemical disequilibrium conditions. However, transmission spectra of exoplanets has been limited in its ability to observational confirm these theories due to the limited wavelength coverage of HST and inferences of single molecules, mostly H2O. In this work, we present the panchromatic transmission spectrum of the approximately 750 K, low-density, Neptune-sized exoplanet WASP-107b using a combination of HST WFC3, JWST NIRCam and MIRI. From this spectrum, we detect spectroscopic features due to H2O (21σ), CH4 (5σ), CO (7σ), CO2 (29σ), SO2 (9σ), and NH3 (6σ). The presence of these molecules enable constraints on the atmospheric metal enrichment (M/H is 10--18× Solar), vertical mixing strength (log10Kzz=8.4--9.0 cm2s1), and internal temperature (>345 K). The high internal temperature is suggestive of tidally-driven inflation acting upon a Neptune-like internal structure, which can naturally explain the planet's large radius and low density. These findings suggest that eccentricity driven tidal heating is a critical process governing atmospheric chemistry and interior structure inferences for a majority of the cool (<1,000K) super-Earth-to-Saturn mass exoplanet population.

G. Munoz-Sanchez, S. de Wit, A.Z. Bonanos, K. Antoniadis, K. Boutsia, P. Boumis, E. Christodoulou, M. Kalitsounaki, A. Udalski

This study delves into [W60] B90, one of the most luminous and extreme Red Supergiants (RSGs) in the Large Magellanic Cloud (LMC), aiming to search for evidence of episodic mass loss. Our discovery of a bar-like nebular structure at 1 pc, reminiscent of the bar around Betelgeuse, raised the question of whether [W60] B90 also has a bow shock. We collected and analyzed proper motion data from Gaia, as well as new multi-epoch spectroscopic and imaging data, and archival time-series photometry in the optical and mid-infrared. We found [W60] B90 to be a walkaway star, with a supersonic peculiar velocity in the direction of the bar. We detected shocked emission between the bar and the star, based on the [S II]/Hα > 0.4 criterion, providing strong evidence for a bow shock. The 30-year optical light curve revealed semi-regular variability, showing three similar dimming events with ΔV1 mag, a recurrence of 12 yr, and a rise time of 400 d. We found the mid-IR light curve to vary by 0.51 mag and 0.37 mag in the WISE1 and WISE2 bands, respectively, and by 0.42 mag and 0.25 mag during the last dimming event. During this event, optical spectroscopy revealed spectral variability (M3I to M4I), a correlation between the Teff and the brightness, increased extinction, and, after the minimum, spectral features incompatible with the models. We also found a difference of >300 K between the Teff measured from the TiO bands in the optical and the atomic lines from our J-band spectroscopy. We inferred that [W60] B90 is a more massive analog of Betelgeuse in the LMC and the first extragalactic single RSG with a suspected bow shock. Its high luminosity log(L/L)=5.32 dex, mass-loss rate, and mid-IR variability compared to other RSGs in the LMC, indicate that it is in an unstable evolutionary state undergoing episodes of mass loss.

In this study, we utilize a sample of 338 galaxies within the redshift range of 0.02<z<0.1, drawn from the Sloan Digital Sky Survey (SDSS), for which there are available classifications, based on their emission line ratios. We, further, identify and select Compton-thick (CT) AGN through the use of X-ray and infrared luminosities at 12μm. We construct the spectral energy distributions (SEDs) for all sources and fit them using the CIGALE code to derive properties related to both the AGN and host galaxies. Employing stringent criteria to ensure the reliability of SED measurements, our final sample comprises 14 CT AGN, 118 Seyfert 2 (Sy2), 82 composite, and 124 LINER galaxies. Our analysis reveals that, irrespective of their classification, the majority of the sources lie below the star-forming main-sequence (MS). Additionally, a lower level of AGN activity is associated with a closer positioning to the MS. Utilizing the Dn4000 spectral index as a proxy for the age of stellar populations, we observe that LINERs exhibit the oldest stellar populations compared to other AGN classes. Conversely, CT sources are situated in galaxies with the youngest stellar populations. Furthermore, LINER and composite galaxies tend to show the lowest accretion efficiency, while CT AGN, on average, display the most efficient accretion among the four AGN populations. Our findings are consistent with a scenario in which the different AGN populations might not originate from the same AGN activity burst. Early triggers in gas rich environments can create high accretion rate SMBHs leading to a progression from CT to Sy2, while later triggers in gas poor stages result in low accretion rate SMBHs like those found in LINERs.

E. Spitoni, F. Matteucci, R. Gratton, B. Ratcliffe, I. Minchev, G. Cescutti

The analysis of several spectroscopic surveys indicates the presence of a bimodality between the disc stars in the abundance ratio space of [α/Fe] versus [Fe/H]. The two stellar groups are commonly referred to as the high-α and low-α sequences. Some models capable of reproducing such a bimodality, invoke the presence of a hiatus in the star formation history in our Galaxy, whereas other models explain the two sequences by means of stellar migration. Our aim is to show that the existence of the gap in the star formation rate between high-α and low-α is evident in the stars of APOGEE DR17, if one plots [Fe/α] versus [α/H], thus confirming previous suggestions by Gratton et al. (1996) and Fuhrmann (1998). Then we try to interpret the data by means of detailed chemical models. We compare the APOGEE DR17 red giant stars with the predictions of a detailed chemical evolution model based on the two-infall paradigm, taking also into account possible accretion of dwarf satellites. The APOGEE DR17 abundance ratios [Fe/α] versus [α/H] exhibit a sharp increase of [Fe/α] at a nearly constant [α/H] (where α elements considered are Mg, Si, O) during the transition between the two disc phases. This observation strongly supports the hypothesis that a hiatus in star formation occurred during this evolutionary phase. Notably, the most pronounced growth in the [Fe/α] versus [α/H] relation is observed for oxygen, as this element is exclusively synthesised in core-collapse supernovae. A chemical model predicting a stop in the star formation of a duration of roughly 3.5 Gyr, and where the high-α disc starts forming from pre-enriched gas by a previous encounter with a dwarf galaxy can well explain the observations.

David K. Sing (1, 2), Zafar Rustamkulov (1), Daniel P. Thorngren (2), Joanna K. Barstow (3), Pascal Tremblin (4, 5), Catarina Alves de Oliveira (6), Tracy L. Beck (7), Stephan M. Birkmann (6), Ryan C. Challener (8), Nicolas Crouzet (9), Néstor Espinoza (7), Pierre Ferruit (6), Giovanna Giardino (10), Amélie Gressier (7), Elspeth K. H. Lee (11), Nikole K. Lewis (8), Roberto Maiolino (12), Elena Manjavacas (2, 13), Bernard J. Rauscher (14), Marco Sirianni (15), Jeff A. Valenti (7) ((1) Department of Earth &amp; Planetary Sciences, Johns Hopkins University, (2) Department of Physics &amp; Astronomy, Johns Hopkins University, (3) School of Physical Sciences, The Open University, (4) Université Paris-Saclay, UVSQ, CNRS, CEA, Maison de la Simulation, (5) Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, (6) European Space Agency, European Space Astronomy Centre, (7) Space Telescope Science Institute, (8) Department of Astronomy and Carl Sagan Institute, Cornell University, (9) Leiden Observatory, Leiden University, (10) ATG Europe for the European Space Agency, ESTEC, (11) Center for Space and Habitability, University of Bern, (12) University of Cambridge, (13) AURA for the European Space Agency, (14) NASA Goddard Space Flight Center, (15) European Space Agency, ESA Office, STScI)

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Observations of transiting gas giant exoplanets have revealed a pervasive depletion of methane, which has only recently been identified atmospherically. The depletion is thought to be maintained by disequilibrium processes such as photochemistry or mixing from a hotter interior. However, the interiors are largely unconstrained along with the vertical mixing strength and only upper limits on the CH4 depletion have been available. The warm Neptune WASP-107 b stands out among exoplanets with an unusually low density, reported low core mass, and temperatures amenable to CH4 though previous observations have yet to find the molecule. Here we present a JWST NIRSpec transmission spectrum of WASP-107 b which shows features from both SO2 and CH4 along with H2O, CO2, and CO. We detect methane with 4.2σ significance at an abundance of 1.0±0.5 ppm, which is depleted by 3 orders of magnitude relative to equilibrium expectations. Our results are highly constraining for the atmosphere and interior, which indicate the envelope has a super-solar metallicity of 43±8× solar, a hot interior with an intrinsic temperature of Tint=460±40 K, and vigorous vertical mixing which depletes CH4 with a diffusion coefficient of Kzz = 1011.6±0.1 cm2/s. Photochemistry has a negligible effect on the CH4 abundance, but is needed to account for the SO2. We infer a core mass of 11.5+3.03.6 M, which is much higher than previous upper limits, releasing a tension with core-accretion models.

Angel Hernandez (CU Boulder, LANL), Roseanne M. Cheng (LANL, UNM), Nicole M. Lloyd-Ronning (LANL, UNM-LA), Carl E. Fields (LANL, University of Arizona)

Although the association of gamma-ray bursts (GRBs) with massive stellar death is on firm footing, the nature of the progenitor system and the key ingredients required for a massive star to produce a gamma-ray burst remain open questions. Here, we investigate the evolution of a massive star with a closely orbiting compact object companion using the stellar evolution code MESA. In particular, we examine how the companion influences the angular momentum and circumstellar environment near the end of the massive star life. We find that tidal effects can cause the compact object companion to significantly increase the angular momentum of the massive star, for orbital periods in the range of up to 4 days. We model the density profile evolution of the massive star and discuss how tidal interactions may also lead to stripping of the outer stellar envelope in a way that can create an environment around the binary system that deviates from a typical 1/r2 wind density profile. We show how our results depend on the metallicity of the system, initial spin of the star, mass ratio, as well as accretion and dynamo prescriptions in the simulations. We conclude that these systems may be viable progenitors for radio-bright, long gamma-ray bursts.

Henize 2-10 is a dwarf galaxy experiencing positive black hole (BH) feedback from a radio-detected low-luminosity active galactic nucleus. Previous Green Bank Telescope (GBT) observations detected a H2O "kilomaser" in Henize 2-10, but the low angular resolution (33") left the location and origin of the maser ambiguous. We present new Karl G. Jansky Very Large Array observations of the H2O maser line at 22.23508 GHz in Henize 2-10 with ~2" resolution. These observations reveal two maser sources distinct in position and velocity. The first maser source is spatially coincident with the known BH outflow and the region of triggered star formation ~70 pc to the east. Combined with the broad width of the maser (W50 ~ 66 km s-1), this confirms our hypothesis that part of the maser detected with the GBT is produced by the impact of the BH outflow shocking the dense molecular gas along the flow and at the interface of the eastern star-forming region. The second maser source lies to the south-east far from the central BH and has a narrow width (W50 ~ 8 km s-1), suggesting a star-formation-related origin. This work has revealed the nature of the H2O kilomaser in Henize 2-10 and illustrates the first known connection between outflow-driven H2O masers and positive BH feedback.

L. D. Anderson, Matteo Luisi, B. Liu, Dylan J. Linville, Robert A. Benjamin, Natasha Hurley-Walker, N. M. McClure-Griffiths, Catherine Zucker

The Galactic center lobe (GCL) is an object ~1° across that is located north of the Galactic center. In the mid-infrared (MIR) the GCL appears as two 8.0μm filaments between which is strong 24μm and radio continuum emission. Due to its morphology and location in the sky, previous authors have argued that the GCL is located in the Galactic center region, created by outflows from star formation or by activity of the central black hole Sagittarius A*. In an associated paper (Hurley-Walker et al., 2024, in press), low-frequency radio emission indicates that the GCL must instead lie foreground to the Galactic center. If the GCL is foreground to the Galactic center, it is likely to be a type of object common throughout the Galactic disk; we here investigate whether its properties are similar to those of Galactic HII regions. We find that the GCL's MIR morphology, MIR flux densities, dust temperatures, and radio recombination line (RRL) properties as traced by the GBT Diffuse Ionized Gas Survey (GDIGS) are consistent with those of known Galactic HII regions, although the derived electron temperature is low. We search for the ionizing source(s) of the possible HII region and identify a stellar cluster candidate (Camargo #1092/Ryu & Lee #532) and a cluster of young stellar objects (SPICY G359.3+0.3) whose members have Gaia parallaxes distances of 1.7±0.4kpc. Taken together, the results of our companion paper and those shown here suggest that the GCL has properties consistent with those of an HII region located ~2kpc from the Sun.

William Grimble, Joel Kastner, Christophe Pinte, Beth Sargent, David A. Principe, Annie Dickson-Vandervelde, Aurora Belen Aguayo, Claudio Caceres, Matthias R. Schreiber, Keivan G. Stassun

Our understanding of how exoplanets form and evolve relies on analyses of both the mineralogy of protoplanetary disks and their detailed structures; however, these key complementary aspects of disks are usually studied separately. We present initial results from a hybrid model that combines the empirical characterization of the mineralogy of a disk, as determined from its mid-infrared spectral features, with the MCFOST radiative transfer disk model, a combination we call the EaRTH Disk Model. With the results of the mineralogy detection serving as input to the radiative transfer model, we generate mid-infrared spectral energy distributions (SEDs) that reflect both the mineralogical and structural parameters of the corresponding disk. Initial fits of the SED output by the resulting integrated model to Spitzer Space T elescope mid-infrared (IRS) spectra of the protoplanetary disk orbiting the nearby T Tauri star MP Mus demonstrate the potential advantages of this approach by revealing details like the dominance of micron-sized olivine and micron-sized forsterite in this dusty disk. The simultaneous insight into disk composition and structure provided by the EaRTH Disk methodology should be directly applicable to the interpretation of mid-infrared spectra of protoplanetary disks that will be produced by the James Webb Space Telescope.

An hourglass-shaped magnetic field pattern arises naturally from the gravitational collapse of a star-forming gas cloud. Most studies have focused on the prestellar collapse phase, when the structure has a smooth and monotonic radial profile. However, most observations target dense clouds that already contain a central protostar, and possibly a circumstellar disk. We utilize an analytic treatment of the magnetic field along with insights gained from simulations to develop a more realistic magnetic field model for the protostellar phase. Key elements of the model are a strong radial magnetic field in the region of rapid collapse, an off-center peak in the magnetic field strength (a consequence of magnetic field dissipation in the circumstellar disk), and a strong toroidal field that is generated in the region of rapid collapse and outflow generation. A model with a highly pinched and twisted magnetic field pattern in the inner collapse zone facilitates the interpretation of magnetic field patterns observed in protostellar clouds.

The {\em bulk flow} in the Local Universe is a collective phenomenon due to the peculiar motions of matter structures, which, instead of moving in random directions, appears to follow an approximate dipole velocity flow. We apply a directional analysis to investigate, through the Hubble-Lema\^ıtre diagram, the angular dependence of the Hubble constant H0 of a sample of Type Ia Supernovae from the Pantheon+ catalog in the Local Universe (0.015z0.06). We perform a directional analysis that reveals a statistically significant dipole variation of H0, at more than 99.9% confidence level, showing that matter structures follow a dipole bulk flow motion towards (l,b)=(326.1±11.2,27.8±11.2), close to the Shapley supercluster (l\scalebox0.6Shapley,b\scalebox0.6Shapley)=(311.5,32.3), with velocity 132.14±109.3 km s1 at the effective distance 102.83±10.2~Mpc. Interestingly, the antipodal direction of this dipole points close to the Dipole Repeller structure. Our analyses confirm that the gravitational dipole system Shapley-Dipole Repeller explains well the observed bulk flow velocity field in the Local Universe. Furthermore, we performed robustness tests that support our results. Additionally, our approach provides a measurement of the Hubble constant H0=70.39±1.4~\text{km s1 Mpc1}, at the effective distance 102.8~Mpc, z0.025.

Howard E. Bond (1, 2), Akshat S. Chaturvedi (1), Robin Ciardullo (1), Klaus Werner (3), Gregory R. Zeimann (4), Michael H. Siegel (1) ((1) Pennsylvania State Univ., (2) Space Telescope Science Institute, (3) Eberhard Karls Univ. Tuebingen, (4) Hobby-Eberly Telescope)

During our spectroscopic survey of central stars of faint planetary nebulae (PNe), we found that the nucleus of Abell 57 exhibits strong nebular emission lines. Using synthetic narrow-band images, we show that the emission arises from an unresolved compact emission knot (CEK) coinciding with the hot (90,000 K) central star. Thus Abell 57 belongs to the rare class of "EGB 6-type" PNe, characterized by dense emission cores. Photometric data show that the nucleus exhibits a near-IR excess, due to a dusty companion body with the luminosity of an M0 dwarf but a temperature of ~1800 K. Emission-line analysis reveals that the CEK is remarkably dense (electron density ~1.6x10**7 cm**-3), and has a radius of only ~4.5 AU. The CEK suffers considerably more reddening than the central star, which itself is more reddened than the surrounding PN. These puzzles may suggest an interaction between the knot and central star; however, Hubble Space Telescope imaging of EGB 6 itself shows that its CEK lies more than ~125 AU from the PN nucleus. We discuss a scenario in which a portion of the AGB wind that created the PN was captured into a dust cloud around a distant stellar companion; this cloud has survived to the present epoch, and has an atmosphere photoionized by radiation from the hot central star. However, in this picture EGB 6-type nuclei should be relatively common, yet they are actually extremely rare; thus they may arise from a different transitory phenomenon. We suggest future observations of Abell 57 that may help unravel its mysteries.

Gerd Pühlhofer, Fabian Leuschner, Heiko Salzmann

The High Energy Stereoscopic System H.E.S.S. is an array of Cherenkov Telescopes located in the Khomas Highlands in Namibia. H.E.S.S. started operations in 2003 and has been operated very successfully since then. With its location in the Southern hemisphere, the system provides a privileged view of the Milky Way and the Galactic center region. With H.E.S.S., a large variety of new TeV emitters has been discovered, both in our Galaxy and in extragalactic space. We provide a description of the individual telescopes and of the system as a whole, and review the scientific highlights that have been achieved with the instrument.

Edward W. Schwieterman, Thomas J. Fauchez, Jacob Haqq-Misra, Ravi K. Kopparapu, Daniel Angerhausen, Daria Pidhorodetska, Michaela Leung, Evan L. Sneed, Elsa Ducrot

Atmospheric pollutants such as CFCs and NO2 have been proposed as potential remotely detectable atmospheric technosignature gases. Here we investigate the potential for artificial greenhouse gases including CF4, C2F6, C3F8, SF6, and NF3 to generate detectable atmospheric signatures. In contrast to passive incidental byproducts of industrial processes, artificial greenhouse gases would represent an intentional effort to change the climate of a planet with long-lived, low toxicity gases and would possess low false positive potential. An extraterrestrial civilization may be motivated to undertake such an effort to arrest a predicted snowball state on their home world or to terraform an otherwise uninhabitable terrestrial planet within their system. Because artificial greenhouse gases strongly absorb in the thermal mid-infrared window of temperate atmospheres, a terraformed planet will logically possess strong absorption features from these gases at mid-IR wavelengths (8-12 μm), possibly accompanied by diagnostic features in the near-IR. As a proof of concept, we calculate the needed observation time to detect 1 [10](100) ppm of C2F6/C3F8/SF6 on TRAPPIST-1f with JWST MIRI/LRS and NIRSpec. We find that a combination of 1[10](100) ppm each of C2F6, C3F8, and SF6 can be detected with an S/N 5 in as few as 25[10](5) transits with MIRI/LRS. We further explore mid-infrared direct-imaging scenarios with the LIFE mission concept and find these gases are more detectable than standard biosignatures at these concentrations. Consequently, artificial greenhouse gases can be readily detected (or excluded) during normal planetary characterization observations with no additional overhead.

We synthesize JWST NIRCam photometry for the F164N, F187N, F212N narrow filters, F140M, F162M, F182M, F210M medium filters, and F115W, F150W, F200W wide filters, Euclid Near Infrared Spectrometer and Photometer (NISP) photometry for the YEJEHE filters, and Roman Wide Field Instrument (WFI) photometry for the F106, F129, F146, F158, F184 and F213 filters using SpeX prism spectra and parallaxes of 688 field-age and 151 young ( 200 Myr) ultracool dwarfs (spectral types M6-T9). We derive absolute magnitude-spectral type polynomial relations that enable the calculation of photometric distances for ultracool dwarfs observed with JWST, and to be observed with Euclid and Roman, in the absence of parallax measurements. Additionally, using the synthesized photometry to generate color-color figures can help distinguish high-redshift galaxies from brown dwarf interlopers in survey datasets. In particular, anticipating the upcoming Euclid Early Release Observations, we provide synthetic Euclid colors for ultracool dwarfs in our sample.

In an earlier paper, we determined the morphological types of galaxies in the Coma Cluster using data from the HST/ACS Coma Cluster treasury survey. We found that of the 132 members, 51 are non dwarfs and 81 are dwarfs. We define dwarfs to have a absolute luminosity M_{F814W}\geq -18.5 as in \cite{2012ApJ...746..136M}. In this paper, we determine the morphological types of these dwarf galaxies and make a detailed study of their properties. Using GALFIT, we determine the structural properties of our sample and with spectroscopic redshifts, we determined memberships and distances to identify dwarfs. A visual examination of the residual images reveals that our sample of 78 dwarf galaxies comprises of: dwarf lenticular (\textit{dS0}) 22\%, dwarf Elliptical (dE) 69\%, dwarf spirals (\textit{dSp}) 4\%, dwarf ring (\textit{dring}) 1\%, dwarf barred spirals (\textit{dSBp}) 3\% and dwarf irregular (\textit{dIrr}) 1\% galaxies. We find that the bulge-disk decomposition (Sérsic + exponential) fits are good only for the \textit{dS0} galaxies. The remainder of the sample gives good fits only for single Sérsic fits. The Colour Magnitude Relation (CMR) shows that the dEs are redder and fainter than the rest of the sample (except one dIrr galaxy). The Kormendy relation reveals that dE galaxies have lower surface brightness than the rest of the sample. Our research leads us to the conclusion that dwarf galaxies appear to have a different formation and evolution process than non-dwarf galaxies.

Observations have definitively strengthened the long-standing assertion that binaries are crucial in massive star evolution. While the percentage of spectroscopic binary systems among main-sequence O stars is well-studied, other phases of massive star evolution remain less explored. We aim to estimate the spectroscopic binary fraction in Galactic late O- and B-type supergiants (OB-Sgs) and set empirical thresholds in radial velocity (RV) to avoid misidentifying pulsating stars as single-line spectroscopic binaries. Using over 4500 high-resolution spectra of 56 Galactic OB-Sgs (plus 13 O dwarfs/subgiants and 5 early-B giants) from the IACOB project (2008-2020), we apply Gaussian fitting and centroid computation techniques to measure RV for each spectrum. Our findings reveal that intrinsic variability in OB-Sgs can result in peak-to-peak RV amplitudes (RVpp) of up to 20-25 km/s, notably in late-O and early-B Sgs, and decreases to typical values of RVpp in the range of 1-5 km/s for O dwarfs and 2-15 km/s for late B-Sgs. Considering these results and evaluating line-profile variability in each star, we find that 10\pm4% of OB-Sgs are clearly single-line spectroscopic binaries. In addition, we find that the percentage of double-line spectroscopic binaries in late O- and early B-Sgs is ~6%, much lower than the ~30% in O-type dwarfs and giants. This study, along with prior research on B-Sgs in the 30 Doradus region of the LMC, indicates that the spectroscopic binary percentage decreases by a factor of 4-5 from O stars to B-Sgs. Our study underscores the need for a thorough characterization of spectroscopic variability due to intrinsic sources to reliably determine the spectroscopic binary fraction among OB-Sgs and O-type stars in general, offering valuable insights into the impact of binaries on massive star evolution.

T. Mishenina, M. Pignatari, I.Usenko, C. Soubiran, F.-K. Thielemann, A.Yu. Kniazev, S.A.Korotin, T.Gorbaneva

The oldest stars in the Milky Way are metal-poor with [Fe/H] < -- 1.0, displaying peculiar elemental abundances compared to solar values. The relative variations in the chemical compositions among stars is also increasing with decreasing stellar metallicity, allowing for the pure signature of unique nucleosynthesis processes to be revealed. In this work, we report the atmospheric parameters, main dynamic properties, and the abundances of four metal-poor stars: HE 1523--0901, HD 6268, HD 121135, and HD 195636 (--1.5 > [Fe/H] >--3.0). The abundances were derived from spectra obtained with the HRS echelle spectrograph at the SALT, using both LTE and NLTE approaches. Based on their kinematical properties, we show that HE 1523--0901 and HD 195636 are halo stars with typical high velocities. In particular, HD 121135 displays a peculiar kinematical behaviour, making it unclear whether it is a halo or an accreted star. Furthermore, HD 6268 is possibly a rare prototype of very metal-poor thick disk stars. The abundances derived for our stars are compared with theoretical stellar models and with other stars with similar metallicity values from the literature. HD 121135 is Al-poor and Sc-poor, compared to stars observed in the same metallicity range (--1.62 > [Fe/H] >--1.12). The most metal-poor stars in our sample, HE 1523 -- 0901, HD 6268, and HD 195636, exhibit anomalies that are better explained by supernova models from fast-rotating stellar progenitors for elements up to the Fe group. Compared to other stars in the same metallicity range, their common biggest anomaly is represented by the low Sc abundances. If we consider the elements beyond Zn, HE 1523--0901 can be classified as an r-II star, HD 6268 as an r-I candidate, and HD 195636 and HD 121135 exhibiting a borderline r-process enrichment between limited-r and r-I star.

We present an analysis of the chemical compositions in high-redshift galaxies, with a focus on the nitrogen-enhanced galaxies GN-z11 and CEERS-1019. We use stellar models of massive stars with initial masses ranging from 9 to 120 Msol across various metallicities to deduce the chemical abundances of stellar ejecta for a few light elements (H, He, C, N, O). Our study reveals insights into the chemical processes and elemental synthesis in the early universe. We find that Population III stars, particularly at initial fast equatorial rotation and sampled from a top-heavy initial mass function, as well as stars at Z=10^{-5} with moderate rotation, align closely with observed abundance ratios in GN-z11 and CEERS-1019. These models demonstrate log(N/O) = -0.38, log(C/O) =-0.22 and log(O/H) + 12 = 7.82 at dilution factors of f = 20~100, indicating a good match with observational data. Models at higher metallicities do not match these observations, highlighting the unique role of Population III and extremely metal-poor stars in enhancing nitrogen abundance in high-redshift galaxies. Predictions for other abundance ratios, such as log(He/H) ranging from -1.077 to -1.059 and log{(^{12}C/^{13}C)} from 1.35 to 2.42, provide detailed benchmarks for future observational studies.

We present a new CO observation toward the Type Ia supernova remnant (SNR) 3C 397 using the Nobeyama 45-m radio telescope at an unprecedent angular resolution of \sim18''. We newly found that the CO cloud at V_{\mathrm{LSR}} = 55.7-62.2 km s^{-1} (60 km s^{-1} cloud) shows a good spatial correspondence with the radio continuum shell. We also found an expanding gas motion of the 60 km s^{-1} cloud with an expansion velocity of \sim3 km s^{-1}, which is thought to be formed by the pre-and/or post-supernova feedback. By considering the positions of Galactic spiral arms and the X-ray/HI absorption studies, we concluded that 3C 397 is physically associated with the 60 km s^{-1} cloud rather than the previously known CO cloud at V_{\mathrm{LSR}} \sim30 km s^{-1}. Given that the previously measured pre-shock density is \sim2-5 cm^{-3}, the expanding motion of the 60 km s^{-1} cloud was likely formed by the pre-supernova feedback known as optically thick wind. The scenario is consistent with that 3C 397 exploded inside a wind-blown bubble as a single degenerate system.

R. S. Bagge, C. Foster, F. D'Eugenio, A. Battisti, S. Bellstedt, C. Derkenne, S. Vaughan, T. Mendel, S. Barsanti, K. E. Harborne, S. M. Croom, J. Bland-Hawthorn, K. Grasha, C. D. P. Lagos, S. M. Sweet, A. Mailvaganam, T. Mukherjee, L. M. Valenzuela, J. van de Sande, E. Wisnioski, T. Zafar

We present a study of kinematic asymmetries from the integral field spectroscopic surveys MAGPI and SAMI. By comparing the asymmetries in the ionsied gas and stars, we aim to disentangle the physical processes that contribute to kinematic disturbances. We normalise deviations from circular motion by S_{05}, allowing us to study kinematic asymmetries in the stars and gas, regardless of kinematic temperature. We find a similar distribution of stellar asymmetries in galaxies where we do and do not detect ionised gas, suggesting that whatever is driving the stellar asymmetries does not always lead to gas removal. In both MAGPI and SAMI, we find an anti-correlation between stellar asymmetry and stellar mass, that is absent in the gas asymmetries. After stellar mass and mean-stellar-age matching distributions, we find that at all stellar masses, MAGPI galaxies display larger stellar asymmetry compared to SAMI galaxies. In both MAGPI and SAMI galaxies, we find that star-forming galaxies with old mean-stellar-ages typically have larger asymmetries in their gas compared to their stars, whereas galaxies with young mean-stellar-ages have larger asymmetries in their stars compared to their gas. We suggest that this results from continuous, clumpy accretion of gas.

Multi-wavelength modeling of the synchrotron radiation from relativistic transients such as Gamma-ray Burst (GRB) afterglows is a powerful means of exploring the physics of relativistic shocks and of deriving properties of the explosion, such as the kinetic energy of the associated relativistic outflows. Capturing the location and evolution of the synchrotron cooling break is critical to break parameter degeneracies associated with such modeling. However, the shape of the spectrum above the cooling break, as well as the location and evolution of the break itself can be significantly altered by synchrotron self-Compton (SSC) cooling. We present an observer's guide to applying SSC cooling with and without Klein-Nishina (KN) corrections to GRB afterglow modeling. We provide a publicly available python code to calculate the Compton Y-parameter as a function of electron Lorentz factor, from which we compute changes to the electron distribution, along with KN-corrected afterglow spectra and light curves. In this framework, the canonical synchrotron spectral shapes split into multiple sub-regimes. We summarize each new spectral shape and describe its observational significance. We discuss how KN corrections can account for harder spectra and shallower decline rates observed in some GRB X-ray afterglows. Our overall aim is to provide an easy application of SSC+KN corrections into analytical multi-wavelength modeling frameworks for relativistic transients.

The detection of Keplerian rotation is rare among Class 0 protostellar systems. We have investigated the high-density tracer HCN as a probe of the inner disk in a Class 0 proto-brown dwarf candidate. Our ALMA high angular resolution observations show the peak in the HCN (3-2) line emission arises from a compact component near the proto-brown dwarf with a small bar-like structure and a deconvolved size of \sim50 au. Radiative transfer modelling indicates that this HCN feature is tracing the innermost, dense regions in the proto-brown dwarf where a small Keplerian disk is expected to be present. The limited velocity resolution of the observations, however, makes it difficult to confirm the rotational kinematics of this feature. A brightening in the HCN emission towards the core center suggests that HCN can survive in the gas phase in the inner, dense regions of the proto-brown dwarf. In contrast, modelling of the HCO^{+} (3-2) line emission indicates that it originates from the outer pseudo-disk/envelope region and is centrally depleted. HCN line emission can reveal the small-scale structures and can be an efficient observational tool to study the inner disk properties in such faint compact objects where spatially resolving the disk is nearly impossible.

T. Sperling, J. Eislöffel, C. F. Manara, J. Campbell-White, C. Schneider, A. Frasca, K. Maucó, M. Siwak, B. Fuhrmeister, R. Garcia Lopez

The main goal of this study is to screen the PENELLOPE/UVES targets for outflow activity and find microjets via spectro-astrometry in, e.g., the [OI]\lambda6300 line. In total, 34 T\,Tauri stars of the PENELLOPE survey have been observed with the high resolution slit spectrograph UVES in three different slit positions rotated by 120^\text{o}. Our spectro-astrometric analysis in the [OI]\lambda6300 wind line reveals two newly discovered microjets associated with Sz\,103 and XX\,Cha. Both microjets have an extent of about 0.04 arcseconds, that is, <10\,\text{au}, and we confined their orientation by the three slit observations. Furthermore, we confirm the binary nature of VW\,Cha and CVSO\,109. We present (further) evidence that DK\,Tau\,B and CVSO\,104\,A are spectroscopic binaries. Sz\,115 is tentatively a spectroscopic binary. The origin of the LVC, that is, MHD winds versus photoevaporative winds, of the Sz\,103 and XX\,Cha microjets remains unclear.

We present a novel machine learning framework tailored to detect massive black hole binaries observed by spaceborne gravitational wave detectors like the Laser Interferometer Space Antenna (LISA) and predict their future merger times. The detection is performed via convolutional neural networks that analyze time-evolving Time-Delay Interferometry (TDI) spectrograms and utilize variations in signal power to trigger alerts. The prediction of future merger times is accomplished with reinforcement learning. Here, the proposed algorithm dynamically refines time-to-merger predictions by assimilating new data as it becomes available. Deep Q-learning serves as the core technique of the approach, utilizing a neural network to estimate Q-values throughout the observational state space. To enhance robust learning in a noisy environment, we integrate an actor-critic mechanism that segregates action proposals from their evaluation, thus harnessing the advantages of policy-based and value-based learning paradigms. We leverage merger estimation obtained via template matching with truncated waveforms to generate rewards for the reinforcement learning agent. These estimations come with uncertainties, which magnify as the merger event stretches further into the future. The reinforcement learning setup is shown to adapt to these uncertainties by employing a policy fine-tuning approach, ensuring the reliability of predictions despite the varying degrees of template-matching precision. The algorithm denotes a first step toward a low-latency model that provides early warnings for impending transient phenomena. By delivering timely and accurate forecasts of merger events, the framework supports the coordination of gravitational wave observations with accompanied electromagnetic counterparts, thus enhancing the prospects of multi-messenger astronomy. We use the LISA Spritz data challenge for validation.

Yuhan Yao, Muryel Guolo, Francesco Tombesi, Ruancun Li, Suvi Gezari, Javier A. García, Lixin Dai, Ryan Chornock, Wenbin Lu, S. R. Kulkarni, Keith C. Gendreau, Dheeraj R. Pasham, S. Bradley Cenko, Erin Kara, Raffaella Margutti, Yukta Ajay, Thomas Wevers, Tom M. Kwan, Igor Andreoni, Joshua S. Bloom, Andrew J. Drake, Matthew J. Graham, Erica Hammerstein, Russ R. Laher, Natalie LeBaron, Ashish A. Mahabal, Brendan O'Connor, Josiah Purdum, Vikram Ravi, Huei Sears, Yashvi Sharma, Roger Smith, Jesper Sollerman, Jean J. Somalwar, Avery Wold

We present the tidal disruption event (TDE) AT2022lri, hosted in a nearby (\approx\!144 Mpc) quiescent galaxy with a low-mass massive black hole (10^4\,M_\odot < M_{\rm BH} < 10^6\,M_\odot). AT2022lri belongs to the TDE-H+He subtype. More than 1 Ms of X-ray data were collected with NICER, Swift, and XMM-Newton from 187 d to 672 d after peak. The X-ray luminosity gradually declined from 1.5\times 10^{44}\,{\rm erg\,s^{-1}} to 1.5\times 10^{43}\,{\rm erg\,s^{-1}} and remains much above the UV and optical luminosity, consistent with a super-Eddington accretion flow viewed face-on. Sporadic strong X-ray dips atop a long-term decline are observed, with variability timescale of \approx\!0.5 hr--1 d and amplitude of \approx\!2--8. When fitted with simple continuum models, the X-ray spectrum is dominated by a thermal disk component with inner temperature going from \sim\! 146 eV to \sim\! 86 eV. However, there are residual features that peak around 1 keV, which, in some cases, cannot be reproduced by a single broad emission line. We analyzed a subset of time-resolved spectra with two physically motivated models describing either a scenario where ionized absorbers contribute extra absorption and emission lines or where disk reflection plays an important role. Both models provide good and statistically comparable fits, show that the X-ray dips are correlated with drops in the inner disk temperature, and require the existence of sub-relativistic (0.1--0.3c) ionized outflows. We propose that the disk temperature fluctuation stems from episodic drops of the mass accretion rate triggered by magnetic instabilities or/and wobbling of the inner accretion disk along the black hole's spin axis.

We examine the effects of massive primordial black holes (PBHs) on cosmic structure formation, employing both a semi-analytical approach and cosmological simulations. Our simulations incorporate PBHs with a monochromatic mass distribution centered around 10^6 \ \rm M_{\odot}, constituting a fraction of 10^{-2} to 10^{-4} of the dark matter (DM) in the universe, with the remainder being collision-less particle dark matter (PDM). Additionally, we conduct a \LambdaCDM simulation for comparative analysis with runs that include PBHs. At smaller scales, halos containing PBHs exhibit similar density and velocity dispersion profiles to those without PBHs. Conversely, at larger scales, PBHs can expedite the formation of massive halos and reside at their centers due to the `seed effect'. To analyze the relative distribution of PBH host halos compared to non-PBH halos, we apply nearest-neighbor (NN) statistics. Our results suggest that PBH host halos, through gravitational influence, significantly impact the structure formation process, compared to the \LambdaCDM case, by attracting and engulfing nearby newly-formed minihalos. Should PBHs constitute a fraction of DM significantly larger than \sim10^{-3}, almost all newly-formed halos will be absorbed by PBH-seeded halos. Consequently, our simulations predict a bimodal feature in the halo mass function, with most of the massive halos containing at least one PBH at their core and the rest being less massive non-PBH halos.

The exploration of the universe is experiencing a huge development thanks to the success and possibilities of today's major space telescope missions which can generate measurements and images with a resolution 100 times higher than their precedents. This big ecosystem of observations, aimed at expanding the limits of known science, can be analyzed using personal computers thanks to the implementation of interoperable Virtual Observatory (VO) technologies and massive portals of stellar catalogs and databases. In this context of global analysis of astronomical big data, sonification has the potential of adding a complementary dimension to visualization, enhancing the accessibility of the archives, and offering an alternative strategy to be used when overlapping issues and masking effects are found in purely graphical representations. This article presents a collection of sonification and musification prototypes that explore the case studies of the MILES and STELIB stellar libraries from the Spanish Virtual Observatory (SVO), and the Kepler Objects of Interest light curve database from the Space Telescope Science Institute archive (STScI). The work makes use of automation, machine learning, and deep learning algorithms to offer a palette of resources that could be used in future developments oriented towards an auditory virtual observatory proposal. It includes a user study that provides qualitative and quantitative feedback from specialized and non-specialized users in the fields of Music and Astronomy.

Biosignature detection in the atmospheres of Earth-like exoplanets is one of the most significant and ambitious goals for astronomy, astrobiology, and humanity. Molecular oxygen is among the strongest indicators of life on Earth, but it will be extremely difficult to detect via transmission spectroscopy. We used the Bioverse statistical framework to assess the ability to probe Earth-like O_{\mathrm{2}} levels on hypothetical nearby habitable zone exoplanets (EECs) using direct imaging and high-resolution spectroscopy on the Giant Magellan Telescope (GMT) and the Extremely Large Telescope (ELT). We found that O_{\mathrm{2}} could be probed on up to \sim5 and \sim15 EECs orbiting bright M dwarfs within 20 pc in a 10-year survey on the GMT and ELT, respectively. Earth-like O_{\mathrm{2}} levels could be probed on four known super-Earth candidates, including Proxima Centauri b, within about one week on the ELT and a few months on the GMT. We also assessed the ability of the ELT to test the habitable zone oxygen hypothesis \unicode{x2013} that habitable zone Earth-sized planets are more likely to have O_{\mathrm{2}} \unicode{x2013} within a 10-year survey using Bioverse. Testing this hypothesis requires either \sim1/2 of the EECs to have O_{\mathrm{2}} or \sim1/3 if \eta_{\oplus} is large. A northern hemisphere large-aperture telescope, such as the Thirty Meter Telescope (TMT), would expand the target star pool by about 25%, reduce the time to probe biosignatures on individual targets, and provide an additional independent check on potential biosignature detections.

S. B. Bian, Y. W. Wu, Y. Xu, M. J. Reid, J. J. Li, B. Zhang, K. M. Menten, L. Moscadelli, A. Brunthaler

We report measurements of trigonometric parallax and proper motion for two 6.7 GHz methanol and two 22 GHz water masers located in the far portion of the Sagittarius spiral arm as part of the BeSSeL Survey. Distances for these sources are estimated from parallax measurements combined with 3-dimensional kinematic distances. The distances of G033.64-00.22, G035.57-00.03, G041.15-00.20, and G043.89-00.78 are 9.9\pm0.5, 10.2\pm0.6, 7.6\pm0.5, and 7.5\pm0.3 kpc, respectively. Based on these measurements, we suggest that the Sagittarius arm segment beyond about 8 kpc from the Sun in the first Galactic quadrant should be adjusted radially outward relative to previous models. This supports the suggestion of Xu et al. (2023) that the Sagittarius and Perseus spiral arms might merge in the first quadrant before spiraling inward to the far end of the Galactic bar.

Gargi Sen (IIT Guwahati), Debaprasad Maity (IIT Guwahati), Santabrata Das (IIT Guwahati)

We investigate the structure of relativistic, low-angular momentum, inviscid advective accretion flow in a stationary axisymmetric Kerr-like wormhole (WH) spacetime, characterized by the spin parameter (a_{\rm k}), the dimensionless parameter (\beta), and the source mass (M_{\rm WH}). In doing so, we self-consistently solve the set of governing equations describing the relativistic accretion flow around a Kerr-like WH in the steady state, and for the first time, we obtain all possible classes of global accretion solutions for transonic as well as subsonic flows. We study the properties of dynamical and thermodynamical flow variables and examine how the nature of the accretion solutions alters due to the change of the model parameters, namely energy (\mathcal{E}), angular momentum (\lambda), a_{\rm k}, and \beta. Further, we separate the parameter space in \lambda-\mathcal{E} plane according to the nature of the flow solutions, and study the modification of the parameter space by varying a_{\rm k} and \beta. Moreover, we retrace the parameter space in a_{\rm k}-\beta plane that allows accretion solutions containing multiple critical points. Finally, we calculate the disc luminosity (L) considering free-free emissions for transonic solutions as these solutions are astrophysically relevant and discuss the implication of this model formalism in the context of astrophysical applications.

Here we present a proof of concept for the application of the Variance of Laplacian (VL) method in quantifying the sharpness of optical solar images. We conducted a comprehensive study using over 65,000 individual solar images acquired on more than 160 days. Each image underwent processing using a VL image processing algorithm, which assigns a 'score' based on the sharpness of the solar disk's edges. We studied the scores obtained from images acquired at different conditions. Our findings demonstrate that the sharpness of the images exhibits daily trends that are closely linked to the altitude of the Sun at the observation site. We observed a significant degradation in image quality only below a certain altitude threshold. Furthermore, we compared airmass formulae from the literature with our sharpness observations and concluded that the degradation could be modeled as an Image Sharpness Function (ISF), which exhibits similarities to airmass variations. In addition to assessing image quality, our method has the potential to evaluate the optical atmospheric conditions during daytime observations. Moreover, this technique can be easily and cost-effectively applied to archival or real-time images of other celestial bodies, such as the Moon, bright planets and defocused stars. Given that ISF is unique to each location and sensitive to sky conditions, the development of an ISF is not only beneficial for routine observation preparation but also essential for long-term site monitoring.

R. K. Zamanov, K. A. Stoyanov, V. Marchev, M. Minev, D. Marchev, M. Moyseev, J. Marti, M. F. Bode, R. Konstantinova-Antova, S. Stefanov

We present high resolution (0.06 A/px) spectroscopic observations of the recurrent nova T Coronae Borealis obtained during the last 1.5 years (September 2022 -- January 2024), with the 2.0m RCC telecope of the Rozhen National Astronomical Observatory, Bulgaria. Double-peaked emission is visible in the H-alpha line after the end of the superactive state. We subtract the red giant contribution and measure the distance between the peaks (\Delta v_a) of the line. For the period July 2023 -- January 2024, we find that \Delta v_a is in range 90 < \Delta v_a < 120 km/s. Assuming that the emission is from the accretion disc around the white dwarf, we find average radius of the accretion disc R_{disc} = 89 \pm 19 R_\odot, which is approximately equal to the Roche lobe size of the white dwarf. Our results indicate that tidal torque plays an important role but that the disc can extend up to the Roche lobe of the accreting star.

Pavan Uttarkar, Ryan M. Shannon, Marcus E. Lower, Pravir Kumar, Danny C. Price, A. T. Deller, K. Gourdji

Fast Radio Bursts (FRBs) are short-timescale transients of extragalactic origin. The number of detected FRBs has grown dramatically since their serendipitous discovery from archival data. Some FRBs have also been seen to repeat. The polarimetric properties of repeating FRBs show diverse behaviour and, at times, extreme polarimetric morphology, suggesting a complex magneto-ionic circumburst environment for this class of FRB. The polarimetric properties such as circular polarisation behaviour of FRBs are crucial for understanding their surrounding magnetic-ionic environment. The circular polarisation previously observed in some of the repeating FRB sources has been attributed to propagation effects such as generalised Faraday rotation (GFR), where conversion from linear to circular polarisation occurs due to the non-circular modes of transmission in relativistic plasma. The discovery burst from the repeating FRB~20180301A showed significant frequency-dependent circular polarisation behaviour, which was initially speculated to be instrumental due to a sidelobe detection. Here we revisit the properties given the subsequent interferometric localisation of the burst, which indicates that the burst was detected in the primary beam of the Parkes/Murriyang 20-cm multibeam receiver. We develop a Bayesian Stokes-Q, U, and V fit method to model the GFR effect, which is independent of the total polarised flux parameter. Using the GFR model we show that the rotation measure (RM) estimated is two orders of magnitude smaller and opposite sign (\sim28 rad\,m^{-2}) than the previously reported value. We interpret the implication of the circular polarisation on its local magnetic environment and reinterpret its long-term temporal evolution in RM.

In this letter, we report the observational constraints on a Bianchi type I anisotropic extension of wCDM model with spatial curvature from observational data including Baryon Acoustic Oscillations (BAO), Cosmic chronometers (CC), Big Bang nucleosynthesis (BBN), Pantheon+ (PP) compilation of SNe Ia and SH0ES Cepheid host distance anchors. The anisotropy is found to be of the order 10^{-13}, which interplay with spatial curvature to reduce H_0 tension by \sim 1\sigma as found in the analyses with BAO+CC+BBN+PP combination of data, while no significant effect of anisotropy is observed with BAO+CC+BBN+PPSH0ES combination of data. A closed Universe is favored by wCDM as well as anisotropic wCDM models with spatial curvature in analyses with BAO+CC+BBN+PP combination of data. An observation of an open Universe from wCDM model with spatial curvature in analyses with BAO+CC+BBN+PPSH0ES combination of data and a closed Universe from anisotropic wCDM model with curvature in analyses with same combination of data is made. The quintessence form of dark energy is favored at 95\% CL in both analyses.

The relation between the observed UV continuum slope (\beta) and the infrared excess (IRX) is used as a powerful probe to understand the nature of dust attenuation law in high-redshift galaxies. We present a study of 83 UV-selected galaxies between redshift 0.5 and 0.7 from the AstroSat UV Deep Field north (AUDFn) that encloses the GOODS-north field. Using empirical relation, we estimate the observed IRX of 52 galaxies that are detected in either one or both of the Herschel PACS 100\mum and 160\mum bands. We further utilize the multi-band photometric data in 14 - 18 filters from the UVIT, KPNO, HST, Spitzer, and Herschel telescopes to perform spectral energy distribution (SED) modeling. Both the observed and model-derived IRX - \beta values show a large scatter within the span of previously known relations, signifying diversity in dust attenuation. We found a distinct relation between the best-fit power law slope of the modified Calzetti relation (\delta) in the IRX - \beta plane: where the steeper SMC-like attenuation law prefers lower \delta values. Our SED model based IRX - \beta relation shows a preference for steeper SMC-like attenuation which we further confirm from the agreement between extinction-corrected star formation rates derived using H\alpha emission line and the observed FUV plus reprocessed far-IR fluxes. The current study reveals a strong positive correlation between IRX and the galaxy stellar mass between 10^{9.5} and 10^{11.0} M_{\odot}, signifying increased dust production in more massive star-forming galaxies.

Natasha Hurley-Walker, L. D. Anderson, M. Luisi, N. M. McClure-Griffiths, Robert A. Benjamin, Michael A. Kuhn, Dylan J. Linville, B. Liu, Catherine Zucker

The Galactic center lobe (GCL) is a \sim 1^\circ object located north of the Galactic center. In the mid-infrared (MIR), the GCL appears as two 8.0-micron filaments that roughly define an ellipse. There is strong 24-micron and radio continuum emission in the interior of the ellipse. Due to its morphology and location in the sky, previous authors have argued that the GCL is created by outflows from star formation in the central molecular zone or by activity of the central black hole Sgr~A^*. We present images of the GCL from the GaLactic and Extragalactic All-sky Murchison Widefield Array survey in radio continuum that show thermal absorption against the Galactic center, incompatible with an interpretation of synchrotron self-absorption. Estimates of the cosmic ray emissivity in this direction allow us to place a distance constraint on the GCL. To be consistent with standard emissivity assumptions, the GCL would be located 2kpc away. At a distance of 8kpc, the synchrotron background emissivity is enhanced by \sim75% in the direction of the GCL. We also present radio recombination line data from the Green Bank Telescope that constrains the electron temperature and line widths in this region, which are also more explicable if the GCL lies relatively close.

We study the impacts of magnetic field on the neutrino transport inside core-collapse supernovae (CCSNe). Magnetic field quantizes the momentum of electrons and positrons, resulting in the modification of weak-interaction cross sections and the chemical potentials of electrons and positrons. We include these changes in the leakage scheme of neutrino transport and perform 1D CCSN simulations with GR1D, assuming the postbounce magnetic field strength of 10^{16-17} G. The results show that the neutrino opacities are enhanced due to the amplified interaction rates, resulting in a larger neutrinosphere. This further reduces the peak value of neutrino luminosities and their decay rates since neutrinos stay longer inside the neutrinosphere. Meanwhile, the neutrino mean energies are smaller shortly after bounce and reach their peak values at later times. As these neutrino properties are crucial in subsequent nucleosynthesis processes, including the \nup-process, \nu-process, and r-process, our findings suggest that the magnetic field may leave discernible marks on the abundance pattern of nucleosynthesis in CCSN.

Zhuowen Li, Chunhua Zhu, Guoliang Lü, Lin Li, Helei Liu, Sufen Guo, Jinlong Yu, Xizhen Lu

Wolf-Rayet stars (WRs) are very important massive stars. However, their origin and the observed binary fraction within the entire WR population are still debated. We investigate some possible merger channels for the formation of WRs, including main sequence (MS)/ Hertzsprung Gap (HG) + MS, He + HG/ Giant Branch (GB). We find that many products produced via binary merger can evolve into WRs, the MS/ HG + MS merger channel can explain WRs with luminosities higher than \sim 10^{5.4}\,L_{\odot}, while the He + HG/ GB merger channel can explain low-luminosity WRs in the range of 10^{4.7}\,L_{\odot}\,\sim\,10^{5.5}\,L_{\odot}. In the population synthesis analysis of WRs, we assume an initial binary fraction (f_{\rm ini,bin}) of 50\% and 100\% for massive stars. We also assume that MS/ HG + MS merger products are non-rotating or rapidly rotating (\omega/\omega_{\rm crit}=0.8). In different cases, the calculated single fractions of WRs range from 22.2\% to 60.6\% in the Milky Way (MW) and from 8.3\% to 70.9\% in the Large Magellanic Cloud (LMC). The current observations fall within the range of our calculations. When the merger product of MS/HG+MS rotates rapidly, we estimate that there are approximately 1015 to 1396 WRs in the MW and 128 to 204 WRs in the LMC. Our model also roughly reproduces the observed single-peak luminosity distribution of WRs in the MW. However, the weak bimodal luminosity distribution observed in the LMC is not reproduced in our model. We assess that this may be due to the model underestimating the mass-loss rate in the LMC. In conclusion, we consider that the binary merger is significant formation channel for WR formation, and can explain the observed high fraction of the single WRs in the total population.

Cosmic repulsion represented by a small positive value of the cosmological constant changes significantly properties of central gravitational fields at large distances, leading to existence of a static (or turnaround) radius where gravitational attraction of a center is just balanced by cosmic repulsion. Analyzing behavior of radial timelike geodesics in the Schwarzschild-de Sitter spacetime near its static radius we show that the particles with specific energy close to unity have tendency to slow down and cluster just below the static radius, forming clumps which, subsequently, start to expand uniformly due to cosmic repulsion. For central masses of (10^6-10^{11}){\rm M_{\odot}} and current value of the cosmological constant 1.1\times 10^{-52}\,{\rm m^{-2}}, this phenomenon takes place at distances of tens to hundreds of kiloparsecs from the center, being comparable with distances in which huge radio-lobes from some active galaxies were observed.

Domitilla Tapinassi, Daniele Galli, Marco Padovani, Henrik Beuther

Maps of polarized dust emission of molecular clouds reveal the morphology of the magnetic field associated with star-forming regions. In particular, polarization maps of hub-filament systems show the distortion of magnetic field lines induced by gas flows onto and inside filaments. We aim to understand the relation between the curvature of magnetic field lines associated with filaments in hub-filament systems and the properties of the underlying gas flows. We consider steady-state models of gas with finite electrical resistivity flowing across a transverse magnetic field. We derive the relation between the bending of the field lines and the flow parameters represented by the Alfvén Mach number and the magnetic Reynolds number. We find that, on the scale of the filaments, the relevant parameter for a gas of finite electrical resistivity is the magnetic Reynolds number, and we derive the relation between the deflection angle of the field from the initial direction (assumed perpendicular to the filament) and the value of the electrical resistivity, due to either Ohmic dissipation or ambipolar diffusion. Application of this model to specific observations of polarized dust emission in filamentary clouds shows that magnetic Reynolds numbers of a few tens are required to reproduce the data. Despite significant uncertainties in the observations (the flow speed, the geometry and orientation of the filament), and the idealization of the model, the specific cases considered show that ambipolar diffusion can provide the resistivity needed to maintain a steady state flow across magnetic fields of significant strength over realistic time scales.

S. Hubrig, S. D. Chojnowski, S. P. Jarvinen, I. Ilyin, K. Pan

Context. In chemically peculiar Ap/Bp stars with large-scale organised magnetic fields with a simple centred dipole configuration, the ratio between the maximum and the minimum of the mean magnetic field modulus is of the order of 1.25. Values of 2 or more are observed only for very few Ap/Bp stars and are indicative of a very unusual magnetic field geometry. Aims. Determining the magnetic field structure of Ap/Bp stars is bound to provide a different insight into the physics and the origin of the magnetic fields in early-type stars. In this respect, the Bp star HD 57372 is of particular interest because strongly variable magnetically split lines are observed in HARPS and APOGEE spectra. Methods. We obtained and analysed measurements of the mean magnetic field modulus and of the mean longitudinal magnetic field using near-infrared spectra and optical polarimetric spectra distributed over the stellar rotation period. Results. The mean magnetic field modulus <B> of HD 57372, as estimated from absorption lines that are split via the Zeeman effect and resolved in both optical and near-infrared spectra, is found to vary by an extraordinary amount of about 10 kG. The exceptional value of 3 for the ratio between the maximum and the minimum of the field modulus is indicative of a very unusual geometry of HD 57372's magnetic field. All observable quantities are found to vary in phase with the photometric period of 7.889 days. This includes the longitudinal magnetic field <Bz>, which varies from -6 kG up to 1.7 kG in FORS2 spectra as well as the metal line strengths, whose equivalent widths change by up to 50% of their mean values over the course of the rotation period. The B8 temperature class of HD 57372 also places it among the hottest stars known to exhibit resolved, magnetically split lines.

Raul Wolters, Oksana Iarygina, Ana Achucarro

Rapid-turn slow-roll inflationary trajectories have been shown to be an attractor in two-field models, provided the turn rate is near constant and larger than the slow-roll parameters. These trajectories can produce primordial spectra consistent with current observations on CMB scales. We present the generalized consistency condition for sustained rapid-turn inflationary trajectory with two fields, arbitrary field-space metric and potential valid for any value of the turn rate. This has to be supplemented by a second condition to ensure slow roll evolution. Both conditions together constitute a tool to identify inflationary trajectories with arbitrary values of the turning rate without having to solve the equations of motion. We present a Python package for the numerical identification of regions in field-space and parameter space that allow for rapid-turn trajectories.

Reverberation mapping accurately determines virial black hole masses only for redshifts z < 0.2 by utilizing the relationship between the H\beta broad-line region (BLR) size and the 5100 Angstroms continuum luminosity established with \sim 200 active galactic nuclei (AGN). For quasars at z \sim 2-3 determining the BLR size is time-consuming and limited by seasonal gaps, requiring e.g., \sim 20 years of monitoring of the CIV emission lines. In this work, we demonstrate that an efficient alternative is to use a continuum size-luminosity relation, which can be obtained up to 150 times faster than BLR sizes using photometric reverberation mapping (PRM). We outline the method and its feasibility based on simulations and propose an observational strategy that can be carried out with meter-class telescopes. In particular, we focus on the ESO La Silla 2.2 meter telescope as it is suitable for an efficient PRM campaign. These observations will provide the scaling factor between the accretion disk and the BLR size (for CIV-1350 Angstroms), which is crucial for estimating the masses of black holes at higher redshifts (z \gtrsim 2-3).

The joint detection of the gravitational wave (GW) event GW170817 and the short-duration gamma-ray burst (SGRB) event GRB 170817A, marked the beginning of GW multi-messenger astronomy and confirmed that binary neutron star mergers are progenitors of at least some SGRBs. An estimated joint detection rate of 0.3 - 1.7 per year between the LIGO-Hanford, LIGO-Livingston and Virgo GW network at design sensitivity, and the Fermi Gamma-ray Burst Monitor was predicted. However, to date, the GW170817/GRB 170817A joint detection has been the only event of its kind so far. Taking into account that SGRBs are narrowly beamed and are emitted perpendicular to the orbital plane of the binary system, we propose that previous mergers involving neutron stars, were orientated such that observation of the emitted SGRB along this narrow jet was not possible. To support this hypothesis we have estimated the inclination of the binary systems for previously detected Binary Neutron Star (BNS) and Black Hole Neutron Star (BHNS) mergers through GW analysis. This analysis was performed using BILBY, a Python based Bayesian inference library, to estimate the inclination of the BNS events GW170817 and GW190425, and the BHNS events GW190917_114630 and GW200115_042309. The results obtained in this study indicate that these binaries may have had inclinations greater than 33^{\circ} with respect to the line of sight from Earth, an upper limit on the viewing angle set from observations of GRB 170817A. This then suggests that the observation of the emitted SGRB from these past mergers might not have been possible.

Duncan A. Forbes, Daniel Lyon, Jonah Gannon, Aaron J. Romanowsky, Jean P. Brodie

A number of nearby dwarf galaxies have globular cluster (GC) candidates that require spectroscopic confirmation. Here we present Keck telescope spectra for 15 known GCs and GC candidates that may be associated with a host dwarf galaxy, and an additional 3 GCs in the halo of M31 that are candidates for accretion from a now disrupted dwarf galaxy. We confirm 6 star clusters (of intermediate-to-old age) to be associated with NGC~247. The vast bulk of its GC system remains to be studied spectroscopically. We also confirm the GC candidates in F8D1 and DDO190, finding both to be young star clusters. The 3 M31 halo GCs all have radial velocities consistent with M31, are old and very metal-poor. Their ages and metallicities are consistent with accretion from a low mass satellite galaxy. Finally, three objects are found to be background galaxies -- two are projected near NGC~247 and one (candidate GCC7) is near the IKN dwarf. The IKN dwarf thus has only 5 confirmed GCs but still a remarkable specific frequency of 124.

Wenwen Zuo, Hengxiao Guo, Jingbo Sun, Qi Yuan, Paulina Lira, Minfeng Gu, Philip G. Edwards, Alok C. Gupta, Shubham Kishore, Jamie Stevens, Tao An, Zhen-Yi Cai, Haicheng Feng, Luis C. Ho, Dragana Ilić, Andjelka B. Kovačević, ShaSha Li, Mar Mezcua, Luka Č. Popović, Mouyuan Sun, Tushar Tripathi, Vivian U., Oliver Vince, Jianguo Wang, Junxian Wang, Shu Wang, Xuebing Wu, Zhenya Zheng

To investigate the short-term variability and determine the size of the optical continuum emitting size of intermediate-mass black holes (IMBHs), we carried out high-cadence, multi-band photometric monitoring of a Seyfert 1 galaxy J0249-0815 across two nights, together with a one-night single-band preliminary test. The presence of the broad Ha component in our target was confirmed by recent Palomar/P200 spectroscopic observations, 23 years after Sloan Digital Sky Survey, ruling out the supernovae origin of the broad Ha line. The photometric experiment was primarily conducted utilizing four-channel imagers MuSCAT 3 & 4 mounted on 2-meter telescopes within the Las Cumbres Observatory Global Telescope Network. Despite the expectation of variability, we observed no significant variation (<1.4%) on timescales of 6-10 hours. This non-detection is likely due to substantial host galaxy light diluting the subtle AGN variability. Dual-band preliminary tests and tailored simulations may enhance the possibility of detecting variability and lag in future IMBH reverberation campaigns.

The positive evidence of a nano-hertz gravitational wave background recently found by several pulsar timing array (PTA) collaborations opened up a window to test modified gravity theories in a unique frequency band in parallel to other gravitational wave detection experiments. In particular, the overlap reduction function (ORF) in PTA observation is sensitive to the phase velocity of gravitational waves. In this work, we provide analytical expressions for the coefficients of the multipole moments in the ORF, and utilize these analytical results to study constraints on the phase velocity from the frequency dependent overlap reduction function obtained from the Chinese PTA (CPTA) data. While the data contain large error bars yet, interesting constraints are found in the frequency-dependent ORF in the case of subluminal phase velocity. This makes us expect that the nano-hertz band gravitational wave background will become one of the important arenas for exploring modified gravity theories.

Benjamin Quici, Ross J. Turner, Nicholas Seymour, Natasha Hurley-Walker

The energy coupling efficiency of active galactic nucleus (AGN) outbursts is known to differ significantly with factors including the jet kinetic power, duration of the outburst, and properties of the host galaxy cluster. As such, constraints on their jet power and lifetime functions are crucial to quantify the role of kinetic-mode AGN feedback on the evolution of galaxies since z \sim 1. In this work, we address this issue by measuring the energetics of a sample of 79 low-redshift (0.02 < z < 0.2) remnant radio galaxies compiled from large-sky radio surveys - these objects uniquely probe the full duration of an AGN outburst. The jet kinetic power and outburst duration of each remnant are determined using the RAiSE dynamical model based on the surface brightness distribution observed in multi-frequency radio images. We compare the energetics constrained for this sample to those predicted for mock radio source populations - with various intrinsic functions for jet power and lifetime distributions - to correct for sample selection biases imposed on our sample. The intrinsic jet power and lifetime functions that yield a selection-biased mock population most similar to our observed sample are found using Bayesian inference. Our analysis places robust constraints on assumed power-law indices for the intrinsic jet power and lifetime functions: p(Q)\propto Q^{-1.49\pm0.07} and p(t_{\mathrm{on}})\propto t_{\mathrm{on}}^{-0.97\pm0.12} respectively. We discuss the implication of these findings for feedback-regulated accretion and the self-regulating nature of jet activity. The methodology proposed in this work can be extended to active radio galaxies in future studies.

Wei Liu, Xiang-Dong Shi, Xiao-Hui Fang, Qi-Shan Wang

We report the photometric analysis of SU UMa based on the observations of the Transiting Exoplanet Survey Satellite (TESS). TESS has released a large amount of data, which contains the light curves of a complete superoutburst and three normal outbursts of SU UMa. Based on the observations, the evolution of superhumps during the superoutburst was analyzed. By using the O - C method, the three stages were determined, and the superhump period for each stage was calculated. The mass ratio q=0.137 (1) was estimated based on the stage A superhump method. A periodic oscillation with a period of 2.17(9) days was found in the superhump minimum O - C diagram, which is related to the precession of the accretion disk. We investigated the frequency information of quasiperiodic oscillations (QPOs) in the light curves. An ultralong period QPO of 0.18 days at the time of normal outburst and two ultralong periods QPOs of 0.19 days and 0.285 days in quiescence were found. No QPO was found in the superoutburst.

We report the superhumps analysis of seven SU UMa-type dwarf novae based on the observations of Transiting Exoplanet Survey Satellite (TESS). Superhumps are seen during superoutbursts of SU UMa-type dwarf novae. The month-long data sets of TESS are well suited for studying the variation of superhumps. We selected seven non-eclipsing SU UMa-type dwarf novae with superhumps in which TESS light curves are available and have not yet been studied. The stages A, B, and C of superhumps in superoutbursts were determined by O-C method. The results indicate that not all complete superoutbursts show obvious three stages, such as DT Oct and the second superoutburst of J1730+6247. We calculated the superhump periods for each stage and the mean periods for whole superoutbursts. Taking the stage A superhump method, the mass ratios (M2/M1) were estimated. According to the results, the seven stars are pre-bounce systems with mass ratios ranging from 0.1 to 0.2. By combining the orbital periods and the mean superhump periods, the precession periods were calculated. The results show that the precession periods of the seven SU UMa stars are about 2 days.

The crust region is a tiny fraction of neutron stars, but it has a variety of physical properties and plays an important role in astronomical observations. One of the properties characterizing the crust is the elasticity. In this review, with the approach of asteroseismology, we systematically examine neutron star oscillations excited by crust elasticity, adopting the Cowling approximation. In particular, by identifying the quasi-periodic oscillations observed in magnetar flares with the torsional oscillations, we make a constraint on the nuclear saturation parameters. In addition, we also discuss how the shear and interface modes depend on the neutron star properties. Once one detects an additional signal associated with neutron star oscillations, one can get a more severe constraint on the saturation parameters and/or neutron star properties, which must be a qualitatively different constraint obtained from terrestrial experiments, and help us to complementarily understand astrophysics and nuclear physics.

Baryon acoustic oscillation (BAO) is one of the important standard ruler in cosmology. The results of the latest BAO measurements by Dark Energy Spectroscopic Instrument (DESI) survey has been reported. Cosmology with the varying electron mass model and the early dark energy (EDE) models are regraded as interesting models to resolve the Hubble tension. We present constraints on the varying electron mass model and EDE models by including new DESI data as well as cosmic microwave background by Planck and the conventional BAO data from 6dF, MGS, and DR12 and supernovae light curve data into analysis. Since new DESI BAO data indicates slightly longer sound horizon r_dh than the other BAO observations, for the varying electron mass model, the larger H_0 =69.44\pm 0.84 km/s/Mpc is indicated.

Ke Wang (Kavli PKU), Yifei Ge (PKU), Tapas Baug (Bose National Centre)

Filamentary structure is important for the ISM and star formation. Galactic distribution of filaments may regulate the star formation rate in the Milky Way. However, interstellar filaments are intrinsically complex, making it difficult to study quantitatively. Here, we focus on linear filaments, the simplest morphology that can be treated as building blocks of any filamentary structure. We present the first catalog of 42 ``straight-line'' filaments across the full Galactic plane, identified by clustering of far-IR Herschel HiGAL clumps in position-position-velocity space. We use molecular line cubes to investigate the dynamics along the filaments; compare the filaments with Galactic spiral arms; and compare ambient magnetic fields with the filaments' orientation. The selected filaments show extreme linearity (>10), aspect ratio (7-48), and velocity coherence over a length of 3-40 pc (mostly >10 pc). About 1/3 of them are associated with spiral arms, but only one is located in arm center, a.k.a. ``bones'' of the Milky Way. A few of them extend perpendicular to the Galactic plane, and none is located in the Central Molecular Zone (CMZ) near the Galactic center. Along the filaments, prevalent periodic oscillation (both in velocity and density) is consistent with gas flows channeled by the filaments and feeding the clumps which harbor diverse star formation activities. No correlation is found between the filament orientations with Planck measured global magnetic field lines. This work highlights some of the fundamental properties of molecular filaments and provides a golden sample for follow-up studies on star formation, ISM structure, and Milky Way structure.

J. D. Turner, B. W. Stappers, E. Carli, E. D. Barr, W. Becker, J. Behrend, R. P. Breton, S. Buchner, M. Burgay, D. J. Champion, W. Chen, C. J. Clark, D. M. Horn, E. F. Keane, M. Kramer, L. K ünkel, L. Levin, Y. P. Men, P. V. Padmanabh, A. Ridolfi, V. Venkatraman Krishnan

We present the description and initial results of the TRAPUM (TRAnsients And PUlsars with MeerKAT) search for pulsars associated with supernova remnants (SNRs), pulsar wind nebulae and unidentified TeV emission. The list of sources to be targeted includes a large number of well-known candidate pulsar locations but also new candidate SNRs identified using a range of criteria. Using the 64-dish MeerKAT radio telescope, we use an interferometric beamforming technique to tile the potential pulsar locations with coherent beams which we search for radio pulsations, above a signal-to-noise of 9, down to an average flux density upper limit of 30 \muJy. This limit is target-dependent due to the contribution of the sky and nebula to the system temperature. Coherent beams are arranged to overlap at their 50 per cent power radius, so the sensitivity to pulsars is not degraded by more than this amount, though realistically averages around 65 per cent if every location in the beam is considered. We report the discovery of two new pulsars; PSR J1831-0941 is an adolescent pulsar likely to be the plerionic engine of the candidate PWN G20.0+0.0, and PSR J1818-1502 appears to be an old and faint pulsar that we serendipitously discovered near the centre of a SNR already hosting a compact central object. The survey holds importance for better understanding of neutron star birth rates and the energetics of young pulsars.

The interaction between stellar winds and the partially ionized local interstellar medium (LISM) is quite common in astrophysics. However, the main difficulty in describing the neutral components lies in the fact that the mean free path of an interstellar atom, l, can be comparable to the characteristic size of an astrosphere, L (i.e., the Knudsen number, which is equal to l/L, is approximately equal to 1, as in the case of the heliosphere). In such cases, a single-fluid approximation becomes invalid, and a kinetic description must be used for the neutral component. In this study, we consider a general astrosphere and use a kinetic-gas dynamics model to investigate how the global structure of the astrosphere depends on the Knudsen number. We present numerical results covering an extremely wide range of Knudsen numbers (from 0.0001 to 100). Additionally, we explore the applicability of single-fluid approaches for modeling astrospheres of various sizes. We have excluded the influence of interstellar and stellar magnetic fields in our model to make parametric study of the kinetic effects feasible. The main conclusion of this work is that, for large astrospheres (with a distance to the bow shock greater than 600 AU) a heated rarefied plasma layer forms in the outer shock layer near the astropause. The formation of this layer is linked to localized heating of the plasma by atoms (specifically, ENAs) that undergo charge exchange again behind the astropause. This process significantly alters the flow structure in the outer shock layer and the location of the bow shock, and it cannot be described by a single-fluid model. Additionally, this paper discusses how atoms weaken the bow shocks at near-heliospheric conditions.

James Freeburn, Jeff Cooke, Anais Möller, Dougal Dobie, Jielai Zhang, Om Sharan Salafia, Karelle Siellez, Katie Auchettl, Simon Goode, Timothy M. C. Abbott, Igor Andreoni, Rebecca Allen, Natasha Van Bemmel, Sara Webb

The relativistic outflows that produce Long GRBs (LGRBs) can be described by a structured jet model where prompt \gamma-ray emission is restricted to a narrow region in the jet's core. Viewing the jet off-axis from the core, a population of afterglows without an associated GRB detection can be predicted. In this work, we conduct an archival search for these `orphan' afterglows (OAs) with minute-cadence, deep (g\sim23) data from the Dark Energy Camera (DECam) taken as part of the Deeper, Wider, Faster programme (DWF). We introduce a method to select fast-evolving OA candidates within DWF data that comprises a machine learning model, based on a realistic synthetic population of OAs. Using this classifier, we recover 51 OA candidates. Of these candidates, 42 are likely flare events from M-class stars. The remaining nine possess quiescent, coincident sources in archival data with angular profiles consistent with a star. Comparing these sources to the expected population of LGRB host galaxies, we conclude that these are likely Galactic events. We calculate an upper limit on the rate of OAs down to g<22 AB mag of 2.49 deg^{-2}yr^{-1} using our criteria and constrain the parameter space of possible jet structures. We also place an upper limit of the characteristic angle between the \gamma-ray emitting region and the jet's half opening angle, assuming a shallow angular jet structure with a power-law index of 0.8. These values are 58.3^{\circ} and 56.6^{\circ} for a smooth power-law and a power-law with core jet model respectively.

Margherita Grespan, Hareesh Thuruthipilly, Agnieszka Pollo, Michelle Lochner, Marek Biesiada, Verlon Etsebeth

We apply a state-of-the-art transformer algorithm to 221 deg^2 of the Kilo Degree Survey (KiDS) to search for new strong gravitational lenses (SGL). We test four transformer encoders trained on simulated data from the Strong Lens Finding Challenge on KiDS survey data. The best performing model is fine-tuned on real images of SGL candidates identified in previous searches. To expand the dataset for fine-tuning, data augmentation techniques are employed, including rotation, flipping, transposition, and white noise injection. The network fine-tuned with rotated, flipped, and transposed images exhibited the best performance and is used to hunt for SGL in the overlapping region of the Galaxy And Mass Assembly (GAMA) and KiDS surveys on galaxies up to z=0.8. Candidate SGLs are matched with those from other surveys and examined using GAMA data to identify blended spectra resulting from the signal from multiple objects in a fiber. We observe that fine-tuning the transformer encoder to the KiDS data reduces the number of false positives by 70%. Additionally, applying the fine-tuned model to a sample of \sim 5,000,000 galaxies results in a list of \sim 51,000 SGL candidates. Upon visual inspection, this list is narrowed down to 231 candidates. Combined with the SGL candidates identified in the model testing, our final sample includes 264 candidates, with 71 high-confidence SGLs of which 44 are new discoveries. We propose fine-tuning via real augmented images as a viable approach to mitigating false positives when transitioning from simulated lenses to real surveys. Additionally, we provide a list of 121 false positives that exhibit features similar to lensed objects, which can benefit the training of future machine learning models in this field.

TianFang Zhang, Mamoru Doi, Mitsuru Kokubo, Shigeyuki Sako, Ryou Ohsawa, Nozomu Tominaga, Masaomi Tanaka, Yasushi Fukazawa, Hidenori Takahashi, Noriaki Arima, Naoto Kobayashi, Ko Arimatsu, Shin-ichiro Okumura, Sohei Kondo, Toshihiro Kasuga, Yuki Mori, Yuu Niino

We studied the optical variability of 241 BL Lacs and 83 flat-spectrum radio quasars (FSRQ) from the 4LAC catalog using data from the Tomo-e Gozen Northern Sky Transient Survey, with \sim 50 epochs per blazar on average. We excluded blazars whose optical variability may be underestimated due to the influence of their host galaxy, based on their optical luminosity (L_O). FSRQs with \gamma-ray photon index greater than 2.6 exhibit very low optical variability, and their distribution of standard deviation of repeated photometry is significantly different from that of the other FSRQs (KS test P value equal to 5 \times 10^{-6} ). Among a sample of blazars at any particular cosmological epoch, those with lower \gamma-ray luminosity (L_\gamma) tend to have lower optical variability, and those FSRQs with \gamma-ray photon index greater than 2.6 tend to have low L_\gamma. We also measured the structure function of optical variability and found that the amplitude of the structure function for FSRQs is higher than previously measured and higher than that of BL Lacs at multiple time lags. Additionally, the amplitude of the structure function of FSRQs with high \gamma-ray photon index is significantly lower than that of FSRQs with low \gamma-ray photon index. The structure function of FSRQs of high \gamma-ray photon index shows a characteristic timescale of more than 10 days, which may be the variability timescale of the accretion disk. In summary, we infer that the optical component of FSRQs with high \gamma-ray photon index may be dominated by the accretion disk.

We propose that ultrahigh energy cosmic rays are produced in binary neutron star mergers. Interpreting the highest energy events as r-process nuclei eliminates the need for exotic sources, while the observed near-universal maximum rigidity of ultrahigh energy sources can be understood as due to the uniformity of jets generated by the gravitationally-driven dynamo, given the narrow range of total binary neutron star masses. We discuss evidence for this scenario, and its prediction of coincidences between neutrinos above 10 PeV and gravitational waves.

Anthony Mallama, Richard E. Cole, Jay Respler, Scott Harrington, Ron Lee, Aaron Worley

Observations of Starlink V2 Mini satellites during orbit-raising suggest that SpaceX applies brightness mitigation when they reach a height of 357 km. The mean apparent magnitudes for objects below that height threshold is 2.68 while the mean for those above is 6.46. When magnitudes are adjusted to a uniform distance of 1000 km the means are 4.58 and 7.52, respectively. The difference of 2.94 between distance-adjusted magnitudes above and below threshold implies that mitigation is 93% effective in reducing the brightness of orbit-raising spacecraft. Orbit-raising Mini spacecraft have a smaller impact on astronomical observations than higher altitude on-station spacecraft because they are relatively few in number. They also spend less time traversing the sky and spend longer in the Earth's shadow. These low-altitude objects will be more out-of-focus in large telescopes such as the LSST which reduces their impact, too. However, they attract considerable public attention and airline pilots have reported them as Unidentified Aerial Phenomena.

M.C. Vergara, D.R.G. Schleicher, A. Escala, B. Reinoso, F. Flammini Dotti, A. W. H. Kamlah, M. Liempi, N. Hoyer, N. Neumayer, R. Spurzem

This paper explores the theoretical relation between star clusters and black holes within, focusing on the potential role of Nuclear Star Clusters (NSCs), Globular Clusters (GCs), and Ultra Compact Dwarf Galaxies (UCDs) as environments that lead to black hole formation through stellar collisions. The study aims to identify optimal conditions for stellar collisions in different stellar systems leading to the formation of very massive stars that subsequently collapse into black holes. Data from numerical simulations and observations of diverse stellar systems are analyzed, encompassing various initial conditions, initial mass functions, and stellar evolution scenarios. We compute a critical mass, determined by the interplay of collision time, system age, and initial properties of the star cluster. The efficiency of black hole formation (\epsilon_{\mathrm{BH}}) is defined as the ratio of initial stellar mass divided by critical mass. The study finds out that stellar systems with a ratio of initial stellar mass over critical mass above 1 exhibit high efficiencies of black hole formation, ranging from 30-100\%. While there is some scatter, potentially attributed to complex system histories and the presence of gas, the results highlight the potential for achieving high efficiencies through a purely collisional channel in black hole formation. In conclusion, this theoretical exploration elucidates the connection between star clusters and black hole formation. The study underscores the significance of UCDs, GCs, and NSCs as environments conducive to stellar collisions leading to black hole formation. The defined black hole formation efficiency (\epsilon_{\mathrm{BH}}) is shown to be influenced by the ratio of initial stellar mass to critical mass.

E. Carli, L. Levin, B. W. Stappers, E. D. Barr, R. P. Breton, S. Buchner, M. Burgay, M. Geyer, M. Kramer, P. V. Padmanabh, A. Possenti, V. Venkatraman Krishnan, W. Becker, M. D. Filipović, C. Maitra, J. Behrend, D. J. Champion, W. Chen, Y. P. Men, A. Ridolfi

The sensitivity of the MeerKAT radio interferometer is an opportunity to probe deeper into the population of rare and faint extragalactic pulsars. The TRAPUM (TRAnsients and PUlsars with MeerKAT) collaboration has conducted a radio-domain search for accelerated pulsars and transients in the Small Magellanic Cloud (SMC). This partially targeted survey, performed at L-band (856-1712 MHz) with the core array of the MeerKAT telescope in 2-h integrations, is twice as sensitive as the latest SMC radio pulsar survey. We report the discovery of seven new SMC pulsars, doubling this galaxy's radio pulsar population and increasing the total extragalactic population by nearly a quarter. We also carried out a search for accelerated millisecond pulsars in the SMC Globular Cluster NGC 121 using the full array of MeerKAT. This improved the previous upper limit on pulsed radio emission from this cluster by a factor of six. Our discoveries reveal the first radio pulsar-PWN systems in the SMC, with only one such system previously known outside our galaxy (the "Crab pulsar twin" in the Large Magellanic Cloud, PSR J0540-6919). We associate the 59 ms pulsar discovery PSR J0040-7337, now the fastest spinning radio pulsar in the SMC, with the bow-shock Pulsar Wind Nebula (PWN) of Supernova Remnant DEM S5. We also present a new young pulsar with a 79 ms period, PSR J0048-7317, in a PWN recently discovered in a MeerKAT radio continuum image. Using the multi-beam capability of MeerKAT, we localised our pulsar discoveries, and two previous Murriyang discoveries, to a positional uncertainty of a few arcseconds.

Understanding the formation history of planets is one of the goals of studying exoplanet atmospheres. The atmospheric composition of planets can provide insights into the formation pathways of planets. Even though the mapping of the atmospheric composition onto a formation pathway is not unambiguous, with the increasing sensitivity of modern instruments, we can derive promising constraints. In this work, we aim to understand the formation pathway of WASP-39b. We discuss whether the detection of SO2 in its atmosphere would impact our understanding of the formation of the planet and whether it enables us to determine the formation pathway of the planet with greater accuracy. We used the JWST transit observation of the planet together with the available HST and Spitzer observations. We used a formation model coupled with a radiative transfer retrieval model to derive the planet's atmospheric characteristics and formation history. Furthermore, we used a photochemical model to derive the impact of photochemistry on the atmosphere of the planet. In this work, we show that the planet is most likely to have initiated beyond the CO2 ice line of its natal disk. Furthermore, the planet is likely to have have accreted some planetesimals during its formation. We show that the sulfur abundance in the atmosphere of the planet is probably lower than 2.27 \times 10^{-4}. This abundance indicates that the planet is likely to exhibit a lower metallicity than suggested by the retrievals. Furthermore, such an abundance for sulfur is more likely if WASP-39b had been formed beyond the CO ice line of its natal disk.

Baptiste Klein, Suzanne Aigrain, Michaël Crétignier, Khaled Al Moulla, Xavier Dumusque, Oscar Barragán, Haochuan Yu, Annelies Mortier, Federica Rescigno, Andrew Collier Cameron, Mercedes López-Morales, Nadège Meunier, Alessandro Sozzetti, Niamh K. O'Sullivan

Stellar magnetic activity induces both distortions and Doppler-shifts in the absorption line profiles of Sun-like stars. Those effects produce apparent radial velocity (RV) signals which greatly hamper the search for potentially habitable, Earth-like planets. In this work, we investigate these distortions in the Sun using cross-correlation functions (CCFs), derived from intensive monitoring with the high-precision spectrograph HARPS-N. We show that the RV signal arising from line-shape variations on time-scales associated with the solar rotation and activity cycle can be robustly extracted from the data, reducing the RV dispersion by half. Once these have been corrected, activity-induced Doppler-shifts remain, that are modulated at the solar rotation period, and that are most effectively modelled in the time domain, using Gaussian Processes (GPs). Planet signatures are still best retrieved with multi-dimensonal GPs, when activity is jointly modelled from the raw RVs and indicators of the line width or of the Ca II H and K emission. After GP modelling, the residual RVs exhibit a dispersion of 0.6-0.8 m/s, likely to be dominated by signals induced by super-granulation. Finally, we find that the statistical properties of the RVs evolve significantly over time, and that this evolution is primarily driven by sunspots, which control the smoothness of the signal. Such evolution, which reduces the sensitivity to long-period planet signatures, is no longer seen in the activity-induced Doppler-shifts, which is promising for long term RV monitoring surveys such as the Terra Hunting Experiment or the PLATO follow-up campaign.

We investigated the theoretical possibility of accurately determining the helium-to-metal enrichment ratio \Delta Y/\Delta Z from precise observations of double lined eclipsing binary systems. Using Monte Carlo simulations, we drew synthetic binary systems with masses between 0.85 and 1.00 M_{\odot} from a grid of stellar models with \Delta Y/\Delta Z = 2.0 [...]. Subsequently, a broader grid with \Delta Y/\Delta Z from 1.0 to 3.0 was used in the fitting process. To account for observational uncertainties, two scenarios were explored: S1 with realistic uncertainties of 100 K in temperature and 0.1 dex in [Fe/H], and S2 with halved uncertainties. We repeated the simulation at two baseline metallicities: [Fe/H] = 0.0 and -0.3. The posterior distributions of \Delta Y/\Delta Z were severely biased towards the edge of the allowable range in the S1 errors scenario. The situation only marginally improved when considering the S2 scenario. The effect is due to the impact of changing \Delta Y/\Delta Z in the stellar effective temperature and its interplay with [Fe/H] observational error, and it is therefore not restricted to the specific fitting method. Despite the presence of these systematic discrepancies, the age of the systems were recovered unbiased with 10% precision. Our findings indicate that the observational uncertainty in effective temperature and metallicity significantly hinders the accurate determination of the \Delta Y/\Delta Z parameter from main sequence binary systems.

Théo Duboscq, Natalie B. Hogg, Pierre Fleury, Julien Larena

The analysis of strong lensing images usually involves an external convergence and shear, which are meant to model the effect of perturbations along the line of sight, on top of the main lens. Such a description of line-of-sight perturbations supposes that the corresponding gravitational fields can be treated in the tidal regime. Going one step further introduces additional effects, known as flexion, which have been hitherto neglected in strong lensing. In this work, we build a minimal model for the line-of-sight flexion, which adds four new complex parameters to the lens model. Contrary to convergence and shear, the line-of-sight flexion cannot be projected onto the main lens plane. For a \LambdaCDM cosmology, we predict the typical line-of-sight flexion to be on the order of 10^{-3} \mathrm{arcsec}^{-1} on galactic scales. Neglecting its effect in lens modelling is found to bias the recovery of other parameters; in particular, the line-of-sight shear can be biased up to 2\sigma. Accounting for the line-of-sight flexion in our minimal framework restores accuracy, at the the cost of degrading precision. With current imaging capabilities, the line-of-sight flexion is unlikely to be measurable on individual strong lensing images; it must therefore be considered a nuisance parameter rather than an observable in its own right.

The formation of silicon monosulfide (SiS) in space appears to be a difficult process, but the present work is showing that a previously excluded pathway may contribute to its astronomical abundance. Reaction of the radicals SH + SiH produces SiS with a submerged transition state and generates a stabilizing H_2 molecule as a product to dissipate the kinetic energy. Such is a textbook chemical reaction for favorable gas-phase chemistry. While previously proposed mechanisms reacting atomic sulfur and silicon with SiH, SH, and H_2S will still be major contributors to the production of SiS, an abundance of SiS in certain regions could be a marker for the presence of SiH where it has previously been unobserved. These quantum chemically-computed reaction profiles imply that the silicon-chalcogen chemistry of molecular clouds, shocked regions, or protoplanetary disks may be richer than previously thought. Quantum chemical spectral data for the intermediate cis- and trans-HSiSH are also provided in order to aid in their potential spectroscopic characterization.

L. Marinho, F. Herpin, H. Wiesemeyer, A. López Ariste, A. Baudry, A. Asensio Ramos, A. Lèbre, P. Mathias, M. Montargès

Both magnetic fields and photospheric/atmospheric dynamics can be involved in triggering the important mass loss observed in evolved cool stars. Previous works have revealed that these objects exhibit a magnetic field extending beyond their surface. The origin of this magnetic field is still under debate with mechanisms involving a turbulent dynamo, convection, stellar pulsation, and cool spots. Our goal is to estimate the magnetic field strength in the inner circumstellar envelope of six evolved cool stars (five Miras and one Red Supergiant). Combining this work with previous studies, we tentatively constrain the global magnetic field type observed and shed light on the mechanisms at its origin. Using the XPOL polarimeter installed at the IRAM-30 m telescope, we observed the 28 SiO v = 1, J = 2-1 maser line emission and obtained simultaneous spectroscopic measurements of the four Stokes parameters. Applying a careful calibration method for Stokes Q, U, and V, we derive estimates of the magnetic field strength from the circular and linear polarization fractions considering the saturated and unsaturated maser cases under the Zeeman hypothesis. Magnetic field strengths from several Gauss up to several tens of Gauss are derived. These new and more accurate measurements constraining the field strength in the 2-5 stellar radii region better than previous studies and seem to exclude a global poloidal magnetic field type. A combination of a toroidal and a poloidal field is nevertheless not excluded. A variation of the magnetic field strength over a two-months timescale is observed in one Mira star which suggests a possible link to the stellar phase, i.e. with pulsation/photospheric activity.

L. N. Martínez-Ramírez, G. Calistro Rivera, Elisabeta Lusso, F. E. Bauer, Emanuele Nardini, Johannes Buchner, Michael J.I. Brown, Juan C. B. Pineda, Matthew J. Temple, Manda Banerji, M. Stalevski, Joseph F. Hennawi

We present new frontiers in the modelling of the spectral energy distributions (SED) of active galaxies by introducing the radio-to-X-ray fitting capabilities of the publicly available Bayesian code AGNfitter. The new code release, called AGNfitter-rx, models the broad-band photometry covering the radio, infrared (IR), optical, ultraviolet (UV) and X-ray bands consistently, using a combination of theoretical and semi-empirical models of the AGN and host galaxy emission. This framework enables the detailed characterization of four physical components of the active nuclei: the accretion disk, the hot dusty torus, the relativistic jets/core radio emission, and the hot corona; alongside modeling three components within the host galaxy: stellar populations, cold dust, and the radio emission from the star-forming regions. Applying AGNfitter-rx to a diverse sample of 36 AGN SEDs at z<0.7 from the AGN SED ATLAS, we investigate and compare the performance of state-of-the-art torus and accretion disk emission models on fit quality and inferred physical parameters. We find that clumpy torus models that include polar winds and semi-empirical accretion disk templates including emission line features significantly increase the fit quality in 67% of the sources, by effectively reducing by 2\sigma fit residuals in the 1.5-5 \mu \rm m and 0.7 \mu \rm m regimes.We demonstrate that, by applying AGNfitter-rx on photometric data, we are able to estimate inclination and opening angles of the torus, consistent with spectroscopic classifications within the AGN unified model, as well as black hole mass estimates in agreement with virial estimates based on H\alpha. The wavelength coverage and the flexibility for the inclusion of state-of-the-art theoretical models make AGNfitter-rx a unique tool for the further development of SED modelling for AGNs in present and future radio-to-X-ray galaxy surveys.

Tens of thousands of red giant stars in the Kepler data exhibit solar-like oscillations. Their oscillations enable us to study the internal physics from core to surface, such as differential rotation. However, envelope rotation rates have been measured for only a dozen RGB stars so far. The limited sample hinders the theoretical interpretation of angular momentum transport in post-main-sequence phases. We apply a new approach to calculate the asymptotic frequencies of mixed modes, which accounts for the so-called near-degeneracy effects and leads to more proper measurements of envelope rotation rates. By fitting these asymptotic expressions to the observations, we obtain measurements of the properties of g modes and mean core and envelope rotation rates. Among 2495 stars with clear mixed-mode patterns, we found that 800 show doublets and 1206 show triplets, doubling the size of pre-existing catalogues. This led us to discover an over-density of stars that narrowly distribute around a well-defined ridge in the plane showing core rotation rate versus evolution along the RGB. With this work, we also increase the sample of stars with measured envelope rotation rates by two orders of magnitude. We find a decreasing trend between envelope rotation rates and evolution, implying that the envelopes slow down with expansion, as expected. We find 243 stars whose envelope rotation rates are significantly larger than zero. For these stars, the core-to-envelope rotation ratios are around 20 and show a large spread with evolution. Several stars show extremely mild differential rotations, with core-to-surface ratios between 1 and 2. These stars also have very slow core rotation rates, suggesting that they go through a peculiar rotational evolution. We also discovered more stars located below the degeneracy sequence, which will provide the opportunity to study the history of possible stellar mergers.

We develop a theoretical framework that allows us to explore the coupled motion of neutron-superfluid vortices and proton-superconductor flux tubes in a gravitationally collapsed condensate, which describe neutron stars that form pulsars. Our framework uses the 3D Gross-Pitaevskii-Poisson-Equation (GPPE) for neutron Cooper pairs, the Real-Time-Ginzburg-Landau equation (RTGLE) for proton Cooper pairs, the Maxwell equations for the vector potential {\bf A}, and Newtonian gravity and interactions, both direct and induced by the Poisson equation, between the neutron and proton subsystems. For a pulsar we include a crust potential, characterized by an angle \theta, and frictional drag. By carrying out extensive direct numerical simulations, we obtain a variety of interesting results. We show that a rotating proton superconductor generates a uniform London magnetic field, which changes the field distribution inside flux tubes. In the absence of any direct interaction between the two species, they interact through the gravitational Poisson equation. The presence of attractive (repulsive) density-density interaction leads to the attraction (repulsion) between neutron vortices and proton flux tubes. The inclusion of the current-current interaction and the complete Maxwell equations allows us to quantify the entrainment effect that leads to induced magnetization of neutron vortices. We show that, with a strong external magnetic field {\bf B}_{\rm ext}, proton flux tubes are anchored to the crust, whereas neutron vortices leave the condensate and lead to abrupt changes of the crust angular momentum {\rm J}_c. The frictional term in the dynamical equation for \theta yields stick-slip dynamics that leads, in turn, to glitches in the time series of {\rm J}_c. By calculating various statistical properties of this time series, we demonstrate that they display self-organised criticality(SOC).

Debajyoti Sengupta, Stephen Mulligan, David Shih, John Andrew Raine, Tobias Golling

We present SkyCURTAINs, a data driven and model agnostic method to search for stellar streams in the Milky Way galaxy using data from the Gaia telescope. SkyCURTAINs is a weakly supervised machine learning algorithm that builds a background enriched template in the signal region by leveraging the correlation of the source's characterising features with their proper motion in the sky. This allows for a more representative template of the background in the signal region, and reduces the false positives in the search for stellar streams. The minimal model assumptions in the SkyCURTAINs method allow for a flexible and efficient search for various kinds of anomalies such as streams, globular clusters, or dwarf galaxies directly from the data. We test the performance of SkyCURTAINs on the GD-1 stream and show that it is able to recover the stream with a purity of 75.4% which is an improvement of over 10% over existing machine learning based methods while retaining a signal efficiency of 37.9%.

A. Ritacco, L. Bizzarri, S. Savorgnano, F. Boulanger, M. Pérault, J. Treuttel, P. Morfin, A. Catalano, D. Darson, N. Ponthieu, A. Feret, B. Maffei, A. Chahadih, G. Pisano, M. Zannoni, F. Nati, J. F. Macías-Pérez, A. Monfardini, M. Calvo, M. Murgia, P. Ortu, T. Pisanu, J. Aumont, J. Errard, S. Leclercq, M. Migliaccio

The cosmic microwave background (CMB), a remnant of the Big Bang, provides unparalleled insights into the primordial universe, its energy content, and the origin of cosmic structures. The success of forthcoming terrestrial and space experiments hinges on meticulously calibrated data. Specifically, the ability to achieve an absolute calibration of the polarization angles with a precision of < 0.1 deg is crucial to identify the signatures of primordial gravitational waves and cosmic birefringence within the CMB polarization. We introduce the COSMOCal project, designed to deploy a polarized source in space for calibrating microwave frequency observations. The project aims to integrate microwave polarization observations from small and large telescopes, ground-based and in space, into a unified scale, enhancing the effectiveness of each observatory and allowing robust combination of data. To demonstrate the feasibility and confirm the observational approach of our project, we developed a prototype instrument that operates in the atmospheric window centered at 260 GHz, specifically tailored for use with the NIKA2 camera at the IRAM 30 m telescope. We present the instrument components and their laboratory characterization. The results of tests performed with the fully assembled prototype using a KIDs-based instrument, similar concept of NIKA2, are also reported. This study paves the way for an observing campaign using the IRAM 30m telescope and contributes to the development of a space-based instrument.

Ayush Moharana, K. G. Hełminiak, F. Marcadon, T. Pawar, G. Pawar, M. Konacki, A. Jordán, R. Brahm, N. Espinoza

Eclipsing Compact Hierarchical Triples (ECHTs) are systems with the tertiary star orbiting an eclipsing binary (EB) in an orbit of fewer than 1000 days. In a CHT, all three stars exist in a space less than 5 AU in separation. A low-mass CHT is an interesting case to understand multiple star and planet formation at such small scales. In this study, we combine spectroscopy and photometry to estimate the orbital, stellar and atmospheric parameters of stars in a sample of CHTs. Using the complete set of parameters we aim to constrain the metallicity and age of the systems. We use time-series spectroscopy to obtain radial velocities (RVs) and disentangled spectra. Using RV modelling, EB light curve modelling, and spectral analysis, we estimated the metallicities and temperatures. Using isochrone fitting, we constrain the ages of the system. We then combine observations of masses, outer eccentricities (e_2), orbital periods and age estimates of the systems from the literature. We compare the distributions of e_2, and tertiary mass ratio, q_3 = M_3/(M_1+M_2), for three different metallicity ranges and two ranges of age. We estimate masses, radii, temperatures, metallicities and age of 12 stars in 4 CHTs. The CHT CD-32 6459 shows signs of von Zeipel-Lidov-Kozai oscillations while CD-62 1257 can evolve to form a triple common envelope. The rest of the CHTs are old and have an M-dwarf tertiary. We find that the q_3 distribution for CHTs with sub-solar metallicity has a uniform distribution but the systems with solar and above-solar metallicity peak between 0.5 and 1. When dividing them according to their ages, we found the q_3 of old systems around 0.5. The eccentricity e_2 favours a value around 0.3 irrespective of metallicity or age. The distributions are biased by the lack of observations and observing methods and therefore call for more observations of low-mass CHT.

NASA's Science Mission Directorate (SMD) has initiated a program to enhance the participation of historically underrepresented institutions and communities in NASA's mission. Currently known as the NASA SMD Bridge Program, its goal is to establish enduring partnerships among these institutions, research-intensive universities, and NASA centers. There are concerns about using "Bridge" in the program's name, with stakeholders suggesting that it might stigmatize students and mislead applicants about its focus. In this white paper, we address these concerns and conclude that a name change that better reflects the mission of this SMD effort is necessary to address these concerns.

Several studies in the literature have found a disagreement between data on Baryon Acoustic Oscillations (BAO) derived using two distinct methodologies: the two-dimensional (2D or angular) BAO, which extracts the BAO signal from the analysis of the angular two-point correlation function; and the three-dimensional (3D or anisotropic) BAO, which also exploits the radial clustering signal imprinted on the large-scale structure of the universe. This discrepancy is worrisome, since many of the points contained in these data sets are obtained from the same catalogs of tracers and, therefore, we would expect them to be consistent. Since BAO measurements play a pivotal role in the building of the inverse distance ladder, this mismatch impacts the discourse on the Hubble tension and the theoretical solutions to the latter. So far, the discrepancy between 2D and 3D BAO has been only pointed out in the context of fitting analyses of cosmological models or parametrizations that involve a concrete calibration of the comoving sound horizon at the baryon-drag epoch. In this Letter, we avoid the use of any calibration and cosmological model in the process. At this point we assume that the Etherington (a.k.a distance duality) relation holds. We use state-of-the-art measurements in our analysis, and study how the results change when the angular components of the 3D BAO data from BOSS/eBOSS are substituted by the recent data from DESI Y1. We find the tension to exist at the level of \sim 2\sigma and \sim 2.5\sigma, respectively. We then apply a calibrator-independent method to investigate the robustness of the distance duality relation when analyzed not only with 3D BAO measurements, but also with 2D BAO. We do not find any hint for a violation of the cosmic distance duality relation in any of the considered data sets, although they leave still room for departures from it. [abridged]

In single-field inflation, violation of the slow-roll approximation can lead to growth of curvature perturbation outside the horizon. This violation is characterized by a period with a large negative value of the second slow-roll parameter. At an early time, inflation must satisfy the slow-roll approximation, so the large-scale curvature perturbation can explain the cosmic microwave background fluctuations. At intermediate time, it is viable to have a theory that violates the slow-roll approximation, which implies amplification of the curvature perturbation on small scales. Specifically, we consider ultraslow-roll inflation as the intermediate period. At late time, inflation should go back to the slow roll period so that it can end. This means that there are two transitions of the second slow-roll parameter. In this paper, we compare two different possibilities for the second transition: sharp and smooth transitions. Focusing on effects generated by the relevant cubic self-interaction of the curvature perturbation, we find that the bispectrum and one-loop correction to the power spectrum due to the change of the second slow-roll parameter vanish if and only if the Mukhanov-Sasaki equation for perturbation satisfies a specific condition called Wands duality. We also find in the case of sharp transition that, even though this duality is satisfied in the ultraslow-roll and slow-roll phases, it is severely violated at the transition so that the resultant one-loop correction is extremely large inversely proportional to the duration of the transition.

Cosmic rays (CRs) interact with turbulent magnetic fields in the intestellar medium, generating nonthermal emission. After many decades of studies, the theoretical understanding of their diffusion in the ISM continues to pose a challenge. This study numerically explores a recent prediction termed "mirror diffusion" and its synergy with traditional diffusion mechanism based on gyroresonant scattering. Our study combines 3D MHD simulations of star-forming regions with test particle simulations to analyze CR diffusion. We demonstrate the significance of mirror diffusion in CR diffusion parallel to the magnetic field, when the mirroring condition is satisfied. Our results support the theoretical expectation that the resulting particle propagation arising from mirror diffusion in combination with much faster diffusion induced by gyroresonant scattering resembles a Levy-flight-like propagation. Our study highlights the necessity to reevaluate the diffusion coefficients traditionally adopeted in the ISM based on gyroresonant scattering alone. For instance, our simulations imply a diffusion coefficient \sim10^{27}cm^2/s for particles with a few hundred TeV within regions spanning a few parsecs around the source. This estimate is in agreement with gamma-ray observations, which shows the relevance of our results for understanding of diffuse gamma-ray emission in star-forming regions.

In order to produce appreciable amount of primordial black holes (PBHs), the square amplitude of curvature perturbation must take a large value of \mathcal{O}(0.01), namely, seven digits larger than the value observed by cosmic microwave background radiation (CMB) on large scales. Such a large fluctuation can be achieved by violating slow-roll (SR) condition within a short duration. The best known of such possibilities is the ultraslow-roll (USR) inflation. We calculate the power spectrum of curvature perturbation in a simple single-field inflation model which evolves through SR-USR-SR regimes so that both large-amplitude small-scale fluctuation for PBH formation and small-amplitude large-scale fluctuation as observed by CMB are realized. We further calculate the bispectrum and one-loop correction to the power spectrum induced by the third-order action of curvature perturbation as the beginning of precision cosmology on small scale. As a result we show that single-field inflation model realizing PBH formation is severely constrained by the quantum correction.

The detection of supermassive black holes (SMBHs) in high-redshift luminous quasars may require a phase of rapid accretion, and as a precondition, substantial gas influx toward seed black holes (BHs) from kilo-parsec or parsec scales. Our previous research demonstrated the plausibility of such gas supply for BH seeds within star-forming giant molecular clouds (GMCs) with high surface density (\sim 10^4\,{\rm {\rm M_\odot}\, pc}^{-2}), facilitating ``hyper-Eddington'' accretion via efficient feeding by dense clumps which are driven by turbulence and stellar feedback. This article investigates the impacts of feedback from accreting BHs on this process, including radiation, mechanical jets, and highly relativistic cosmic rays. We run a suite of numerical simulations to explore diverse parameter spaces of BH feedback, including the sub-grid accretion model, feedback energy efficiency, mass loading factor, and initial metallicity. Utilizing radiative feedback models inferred from the slim disk, we find that hyper-Eddington accretion is still achievable, yielding BH bolometric luminosities as high as 10^{41} -- 10^{44}\,\rm erg/s, depending on the GMC properties and specific feedback model assumed. We find the maximum possible mass growth of seed BHs (\Delta M_{\rm BH}^{\rm max}) is regulated by the momentum deposition rate from BH feedback, \dot{p}_{\rm feedback}/(\dot{M}_{\rm BH} c), which leads to an analytic scaling that agrees well with simulations. This scenario predicts the rapid formation of \sim 10^4\,\rm M_\odot intermediate-massive BHs (IMBHs) from stellar-mass BHs within \sim \rm Myr. Furthermore, we examine the impacts of sub-grid accretion models and how BH feedback may influence star formation within these cloud complexes.

Mariano Poisson, Marcelo López Fuentes, Cristina H. Mandrini, Pascal Démoulin, Francisco Grings

Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic flux-ropes (FR). In this study, we use Bayesian methods to analyze line-of-sight magnetograms of emerging ARs. We employ a FR model consisting of a half-torus field structure based on eight parameters. The goal is to derive constrained physical parameters of the originating FR which are consistent with the observations. Specifically, we aim to obtain a precise estimation of the AR tilt angle and magnetic twist at different stages of the emergence process. To achieve this, we propose four temporal methods that correlate the field parameter evolutions with a single coherent FR. These methods differ from each other in the size of the explored parameter space. We test the methods on four bipolar ARs observed with the Michelson Doppler Imager on board the Solar and Heliospheric Observatory. We find that tilt angles are typically consistent between the temporal methods, improving previous estimations at all stages of the emergence. The twist sign derived from the temporal methods is consistent with previous estimations. The standard errors of all the methods used are similar, indicating that they model the observations equally well. These results indicate that the proposed methods can be used to obtain global magnetic parameters of ARs during their early evolution. The derived parameters contribute to a better understanding of the formation of FRs, and the role of ARs in the magnetic recycling process along the solar cycle.

We propose a modified moment matching algorithm to avoid catastrophic failures for sources with a low signal to noise ratio (SNR). The proposed modifications include a method to eliminate non-physical negative pixel values and a forced single iteration with an initial guess derived from co-add measurements when iterative methods are unstable. We correct for all biases in measurements introduced by the method. We find that the proposed modifications allow the algorithm to avoid catastrophic failures in nearly 100\% of the cases, especially at low signal to noise ratio. Additionally, with a reasonable guess from co-add measurements, the algorithm measures the flux, centroid, size, shape and ellipticity with bias statistically consistent with zero. We show the proposed method allows us to measure sources seven times fainter than traditional methods when applied to images obtained from WIYN-ODI. We also present a scheme to find uncertainties in measurements when using the new method to measure astronomical sources.

The optical depth parameterisation is typically used to study the 21-cm signals associated with the properties of the neutral hydrogen (HI) gas and the ionisation morphology during the Epoch of Reionisation (EoR), without solving the radiative transfer equation. To assess the uncertainties resulting from this simplification, we conduct explicit radiative transfer calculations using the cosmological 21-cm radiative transfer (C21LRT) code and examine the imprints of ionisation structures on the 21-cm spectrum. We consider a globally averaged reionisation history and implement fully ionised cavities (HII bubbles) of diameters d ranging from 0.01 Mpc to 10 Mpc at epochs within the emission and the absorption regimes of the 21-cm global signal. The single-ray C21LRT calculations show that the shape of the imprinted spectral features are primarily determined by d and the 21-cm line profile, which is parametrised by the turbulent velocity of the HI gas. It reveals the spectral features tied to the transition from ionised to neutral regions that calculations based on the optical depth parametrisation were unable to capture. We also present analytical approximations of the calculated spectral features of the HII bubbles. The multiple-ray calculations show that the apparent shape of a HII bubble (of d=5 Mpc at z=8), because of the finite speed of light, differs depending on whether the bubble's ionisation front is stationary or expanding. Our study shows the necessity of properly accounting for the effects of line-continuum interaction, line broadening and cosmological expansion to correctly predict the EoR 21-cm signals.

We show for the first time that high-resolution CMB lensing observations can probe structure on sub-galactic scales. In particular, a CMB-HD experiment can probe out to k ~ 55 h/Mpc, corresponding to halo masses of about 10^8 M_{\odot}. Over the range 0.005 h/Mpc < k < 55 h/Mpc, spanning four orders of magnitude, the total lensing signal-to-noise ratio (SNR) from the temperature, polarization, and lensing power spectra is greater than 1900. CMB-HD gains most of the lensing SNR at small scales from the temperature power spectrum, as opposed to the lensing spectrum. These lensing measurements allow CMB-HD to distinguish between cold dark matter (CDM) and non-CDM models that change the matter power spectrum on sub-galactic scales. We also find that CMB-HD can distinguish between baryonic feedback effects and non-CDM models due to the different way each impacts the lensing signal. The kinetic Sunyaev-Zel'dovich (kSZ) power spectrum further constrains non-CDM models that deviate from CDM on the smallest scales CMB-HD measures. For example, CMB-HD can detect 1 keV warm dark matter (WDM) at 30\sigma, or rule out about 7 keV WDM at 95% CL, in a \LambdaWDM + N_{\rm{eff}} + \sum m_\nu + m_{\rm{WDM}} + \log_{10}T_{\rm{AGN}} + A_{\rm{kSZ}} + n_{\rm{kSZ}} model; here T_{\rm{AGN}} characterizes the strength of the feedback, and A_{\rm{kSZ}} and n_{\rm{kSZ}} allow freedom in the amplitude and slope of the kinetic Sunyaev-Zel'dovich power spectrum. We make the CMB-HD Fisher code used here publicly available, and note that it can be modified to use any non-CDM model that changes the matter power spectrum.

Massive particle and antiparticle pair production and oscillation on the horizon form a holographic and massive pair plasma state in the Friedman Universe. Via this state, the Einstein cosmology term (dark energy) interacts with matter and radiation and is time-varying \tilde\Lambda in the Universe's evolution. It is determined by a close set of ordinary differential equations for dark energy, matter, and radiation energy densities. The solutions are unique, provided the initial conditions given by observations. In inflation and reheating, dark energy density decreases from the inflation scale, converting to matter and radiation energy densities. In standard cosmology, matter and radiation energy densities convert to dark energy density, reaching the present Universe. By comparing with \LambdaCDM, quintessence and dark energy interacting models, we show that these results can be the possible solutions for cosmological fine-tuning and coincidence problems.

C. M. Adair, K. Altenmüller, V. Anastassopoulos, S. Arguedas Cuendis, J. Baier, K. Barth, A. Belov, D. Bozicevic, H. Bräuninger, G. Cantatore, F. Caspers, J. F. Castel, S. A. Çetin, W. Chung, H. Choi, J. Choi, T. Dafni, M. Davenport, A. Dermenev, K. Desch, B. Döbrich, H. Fischer, W. Funk, J. Galan, A. Gardikiotis, S. Gninenko, J. Golm, M. D. Hasinoff, D. H. H. Hoffmann, D. Díez Ibáñez, I. G. Irastorza, K. Jakovčić, J. Kaminski, M. Karuza, C. Krieger, Ç. Kutlu, B. Lakić, J. M. Laurent, J. Lee, S. Lee, G. Luzón, C. Margalejo, M. Maroudas, L. Miceli, H. Mirallas, L. Obis, A. Özbey, K. Özbozduman, M. J. Pivovaroff, M. Rosu, J. Ruz, E. Ruiz-Chóliz, S. Schmidt, Y. K. Semertzidis, S. K. Solanki, L. Stewart, I. Tsagris, T. Vafeiadis, J. K. Vogel, M. Vretenar, S. Youn, A. Zhitnitsky, K. Zioutas

It has been previously advocated that the presence of the daily and annual modulations of the axion flux on the Earth's surface may dramatically change the strategy of the axion searches. The arguments were based on the so-called Axion Quark Nugget (AQN) dark matter model which was originally put forward to explain the similarity of the dark and visible cosmological matter densities \Omega_{\rm dark}\sim \Omega_{\rm visible}. In this framework, the population of galactic axions with mass 10^{-6} {\rm eV}\lesssim m_a\lesssim 10^{-3}{\rm eV} and velocity \langle v_a\rangle\sim 10^{-3} c will be accompanied by axions with typical velocities \langle v_a\rangle\sim 0.6 c emitted by AQNs. Furthermore, in this framework, it has also been argued that the AQN-induced axion daily modulation (in contrast with the conventional WIMP paradigm) could be as large as (10-20)\%, which represents the main motivation for the present investigation. We argue that the daily modulations along with the broadband detection strategy can be very useful tools for the discovery of such relativistic axions. The data from the CAST-CAPP detector have been used following such arguments. Unfortunately, due to the dependence of the amplifier chain on temperature-dependent gain drifts and other factors, we could not conclusively show the presence or absence of a dark sector-originated daily modulation. However, this proof of principle analysis procedure can serve as a reference for future studies.

Planets and stars are able to generate coherent large-scale magnetic fields by helical convective motions in their interiors. This process, known as hydromagnetic dynamo, involves nonlinear interaction between the flow and magnetic field. Nonlinearity facilitates existence of bi-stable dynamo branches: a weak field branch where the magnetic field is not strong enough to enter into the leading order force balance in the momentum equation at large flow scales, and a strong field branch where the field enters into this balance. The transition between the two with enhancement of convection can be either subcritical or supercritical, depending on the strength of magnetic induction. In both cases, it is accompanied by topological changes in velocity field across the system; however, it is yet unclear how these changes are produced. In this work, we analyse transitions between the weak and strong dynamo regimes using a data-driven approach, separating different physical effects induced by dynamically active flow scales. Using Dynamic Mode Decomposition, we decompose the dynamo data from direct numerical simulations into different components (modes), identify the ones relevant for transition, and estimate relative magnitudes of their contributions Lorentz force and induction term. Our results suggest that subcritical transition to a strong dynamo is facilitated by a subharmonic instability, allowing for a more efficient mode of convection, and provide a modal basis for reduced-order models of this transition.

The paper utilizes data from the SuperKamiokande solar neutrino detection experiment and analyses them by diffusion entropy analysis and standard deviation analysis. The result indicates that solar neutrinos are subject to Levy flights (anomalous diffusion, superdiffusion). Subsequently, the paper derives the probability density function, represented as Fox H-function, and the governing fractional diffusion equation (fractional Fokker-Planck Equation) for solar neutrino Levy flights.

Needed for cosmological and stellar nucleosynthesis, we are studying the closed-form analytic evaluation of thermonuclear reaction rates. In this context, we undertake a comprehensive analysis of three distinct velocity distributions, namely the Maxwell-Boltzmann distribution, the pathway distribution, and the Mittag-Leffer distribution. We emphasize the utilization of Meijer G-function and Fox H-function which are special functions of mathematical physics.

Magnetic reconnection within a highly magnetized plasma has been seen as a viable mechanism to extract the energy from a rotating black hole, as it can generate negative energy plasmoids in the ergoregion. For a typical accreting black hole, the ergoregion is filled with bulk plasma plunging from the innermost-stable-circular orbit (ISCO). In this study, we present an analytical study of the energy extraction via magnetic reconnection process in the plunging region. In contrast to the toroidal plasma, where the magnetic field cannot be derived from the MHD scheme, the magnetic field in the plunging plasma was determined by the ideal-MHD condition. We derive the global magnetic field structure in a fast reconnection model, and we read the expressions for the energies of plasmoids ejected from the reconnection region, for general stationary and axisymmetric spacetimes. Then, we demonstrate the behaviors of ejected energies varying with the reconnection locations in the Kerr spacetime, and identify the region where a negative-energy plasmoid can be produced. We find that for a certain magnetization there exists a critical value of the black hole spin, beyond which the energy extraction can occur, and the energy extraction is most efficient for the near-extreme black hole. Moreover, we study the conditions necessary for a plasmoid with positive energy to escape to the infinity, a crucial requirement for effective energy extractions. Considering the escaping conditions, we provide the parameter space in the radius-spin plane in which the energy extraction mechanism is effective.

We investigate the prospect of probing massive fields and testing gravitational theories with multi-band observations of gravitational waves emitted from coalescing compact binaries. Focusing on the dipole radiation induced by a massive field, we show that multi-band observations can probe the field with mass ranging from 10^{-16} eV to 10^{-15} eV, a parameter space that cannot be probed by the milli-Hertz band observations alone. Multi-band observations can also improve the constraints obtained with the LIGO-Virgo-KAGRA binaries by up to 3 orders of magnitude in the mass range. Moreover, we show that multi-band observations can discriminate the spin of the field, which cannot be identified with single-band observations.

Recent studies, in the context of consistency conditions for rapid-turn and third order slow-roll inflation in two-field models, raised the question whether this regime can be sustained for more than a few e-folds of expansion. We answer this question in the affirmative by showing that the consistency conditions themselves ensure the longevity of the rapid-turn regime. Furthermore, we prove this for the most general definition of rapid turning (i.e., with a turning rate that is large compared to the slow-roll parameters, but not necessarily large compared to unity), using in the process a generalized consistency condition. We also show that a special class of rapid-turn models, including angular inflation, satisfy a large-(compared to 1)-turn-rate condition even for non-large turning rates.

We explore the generalized f(R,T) modified theory of gravity, where the gravitational Lagrangian is a function of Ricci scalar R and the trace of the energy-momentum tensor T. We derive modified field equations to the linear order of perturbations in the context of f(R,T) model. We then investigate the growth of perturbations in the context of f(R,T) modified gravity. Primary numerical investigations based on matter power spectra diagrams indicates a structure growth suppression in f(R,T) gravity, which exhibits consistency with local measurements. Also, we notice that matter-geometry interaction in f(R,T) model would results in the specific feature named as "matter acoustic oscillations" appeared in matter power spectra diagrams. Moreover, we put constraints on the cosmological parameters of f(R,T) model, utilizing current observations, chiefly cosmic microwave background (CMB), weak lensing, supernovae, baryon acoustic oscillations (BAO), and redshift-space distortions (RSD) data. Numerical results based on MCMC calculations imply that f(R,T) is a qualified theory of modified gravity in reconciling Planck CMB data with local probes of large scale structures, by reporting lower values for the structure growth parameter \sigma_8 compared to the standard model of cosmology.

We give a detailed canonical analysis of the n-dimensional f(Riemann) gravity, correcting the earlier results in the literature. We also write the field equations in the Fischer-Marsden form which is amenable to identifying the non-stationary energy on a spacelike hypersurface. We give pure R^{2} theory as an example.

We study the impact of the expansion of the universe on a broad class of objects, including black holes, neutron stars, white dwarfs, and others. Using metrics that incorporate primordial inhomogeneities, the effects of a hypothetical "center of the universe" on inflation are calculated. Dynamic coordinates for black holes that account for expansions or contractions with arbitrary rates are provided. We consider the possibility that the universe may be bound to evolve into an ultimate state of "total dilution", wherein stable particles are so widely separated that physical communication among them will be impossible for eternity. This is also a scenario of "cosmic virtuality", as no wave-function collapse would occur again. We provide classical models evolving this way, based on the Majumdar-Papapetrou geometries. More realistic configurations, instead, indicate that gravitational forces locally counteract expansion, except in the universe's early stages. We comment on whether quantum phenomena may dictate that total dilution is indeed the cosmos' ultimate destiny.

The upcoming phase of space exploration not only includes trips to Mars and beyond, but also holds great promise for human progress. However, the vulnerability of space habitats to cosmic radiation, which consists of Galactic Cosmic Rays and Solar Particle Events, raises important safety concerns for astronauts and other living things that will accompany them. Research exploring the biological effects of cosmic radiation consists of experiments conducted in space itself and in simulated space environments on Earth. Notably, NASA's Space Radiation Laboratory has taken significant steps forward in simulating cosmic radiation by using particle accelerators, marking a notable advancement in this field. Intriguingly, much of the research emphasis thus far has been on understanding how cosmic radiation impacts living organisms, instead of finding ways to help them resist the radiation. In this paper, we briefly talk about current research on the biological effects of cosmic radiation and propose possible protective measures through biological interventions. In our opinion, biological pathways responsible for coping with stressors on Earth offer potential solutions for protection against the stress caused by cosmic radiation. Additionally, we recommend assessing the effectiveness of these pathways through experiments using particle accelerators to simulate the effects of cosmic radiation.

Christopher L. Carilli, Bojan Nikolic, Laura Torino, Ubaldo Iriso, Nithyanandan Thyagarajan

We demonstrate the Shape-Orientation-Size conservation principle for a 3-element interferometer using aperture plane masking at the ALBA visible synchrotron radiation light source. We then use these data to demonstrate Image Plane Self-Calibration.

According to the Banados-SIlk-West (BSW) effect, two particles moving towards a black hole, can collide near the horizon with an unbounded energy in the center of mass frame. This requires one of particles to have fine-tuned parameters in such a way that the time component of generalized momentum is zero X=0. Thus the existence of such trjectories is a necessary condition for the BSW effect. However, it is insufficient since the forward-in-time condition requires X>0 outside the horizon. We examine this condition for different types of partricles and horizons and find configurations for which the BSW effect is possible. In doing so, we take into account a finite force of unspesified nature exerted on particles. It includes relationships between numbers characterizing the rate with which four-velocity, acceleration and metric functions change near the horizon. For some aforementioned relations, parameters of a system control the sign of X, in other cases they are required for X to be real quantity. In the simplest case of free particles the BSW effect for the Kerr or Kerr-Newman black hole is impossible if a fine-tuned particle has a negative energy, so in this sense combination of the Penrose process and the BSW effect is forbidden.