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Papers for Monday, Apr 28 2025

Papers with local authors

Arnab Lahiry, Adrian E. Bayer, Francisco Villaescusa-Navarro
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Paper 1 — arXiv:2504.17839
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Paper 1 — arXiv:2504.17839

What happens when a black box (neural network) meets a black box (simulation of the Universe)? Recent work has shown that convolutional neural networks (CNNs) can infer cosmological parameters from the matter density field in the presence of complex baryonic processes. A key question that arises is, which parts of the cosmic web is the neural network obtaining information from? We shed light on the matter by identifying the Fourier scales, density scales, and morphological features of the cosmic web that CNNs pay most attention to. We find that CNNs extract cosmological information from both high and low density regions: overdense regions provide the most information per pixel, while underdense regions -- particularly deep voids and their surroundings -- contribute significantly due to their large spatial extent and coherent spatial features. Remarkably, we demonstrate that there is negligible degradation in cosmological constraining power after aggressive cutting in both maximum Fourier scale and density. Furthermore, we find similar results when considering both hydrodynamic and gravity-only simulations, implying that neural networks can marginalize over baryonic effects with minimal loss in cosmological constraining power. Our findings point to practical strategies for optimal and robust field-level cosmological inference in the presence of uncertainly modeled astrophysics.

L. Zalesky, J. R. Weaver, C. J. R. McPartland, G. Murphree, I. Valdes, C. K. Jespersen, S. Taamoli, N. Chartab, N. Allen, S. W. J. Barrow, D. B. Sanders, S. Toft, B. Mobasher, I. Szapudi, B. Altieri, A. Amara, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, S. Bardelli, P. Battaglia, A. Biviano, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, A. Caillat, S. Camera, G. Cañas-Herrera, V. Capobianco, C. Carbone, J. Carretero, S. Casas, F. J. Castander, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, A. Da Silva, H. Degaudenzi, G. De Lucia, A. M. Di Giorgio, H. Dole, F. Dubath, C. A. J. Duncan, X. Dupac, S. Dusini, A. Ealet, S. Escoffier, M. Farina, R. Farinelli, S. Farrens, F. Faustini, S. Ferriol, F. Finelli, P. Fosalba, S. Fotopoulou, M. Frailis, E. Franceschi, M. Fumana, K. George, B. Gillis, C. Giocoli, J. Gracia-Carpio, A. Grazian, F. Grupp, S. Gwyn, S. V. H. Haugan, W. Holmes, I. Hook, F. Hormuth, A. Hornstrup, K. Jahnke, M. Jhabvala, B. Joachimi, E. Keihänen, S. Kermiche, A. Kiessling, B. Kubik, K. Kuijken, M. Kümmel, M. Kunz, H. Kurki-Suonio, A. M. C. Le Brun, D. Le Mignant, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, G. Mainetti

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Paper 10 — arXiv:2504.17867
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Paper 10 — arXiv:2504.17867

The Cosmic Dawn Survey Pre-launch (PL) catalogues cover an effective 10.13 deg$^{2}$ area with uniform deep Spitzer/IRAC data ($m\sim25$ mag, 5$\sigma$), the largest area covered to these depths in the infrared. These data are used to gain new insight into the growth of stellar mass across cosmic history by characterising the evolution of the galaxy stellar mass function (GSMF) through $0.2 < z \leq 6.5$. The total volume (0.62 Gpc$^{3}$) represents a tenfold increase compared to previous works that have explored $z > 3$ and significantly reduces cosmic variance, yielding strong constraints on the abundance of massive galaxies. Results are generally consistent with the literature but now provide firm estimates of number density where only upper limits were previously available. Contrasting the GSMF with the dark matter halo mass function suggests that massive galaxies ($M \gtrsim10^{11}$ M$_{\odot}$) at $z > 3.5$ required integrated star-formation efficiencies of $M/(M_{\rm h}f_{\rm b}) \gtrsim$ 0.25--0.5, in excess of the commonly-held view of ``universal peak efficiency" from studies on the stellar-to-halo mass relation (SHMR). Such increased efficiencies imply an evolving peak in the SHMR at $z > 3.5$ which can be maintained if feedback mechanisms from active galactic nuclei and stellar processes are ineffective at early times. In addition, a significant fraction of the most massive quiescent galaxies are observed to be in place already by $z\sim 2.5$--3. The apparent lack in change of their number density by $z\sim 0.2$ is consistent with relatively little mass growth from mergers. Utilising the unique volume, evidence for an environmental dependence of the galaxy stellar mass function is found all the way through $z\sim 3.5$ for the first time, though a more careful characterisation of the density field is ultimately required for confirmation.

Qichun Liu, Xiaofeng Wang, Jie Lin, Chengyuan Wu, Chunqian Li, V. Alexei Filippenko, G. Thomas Brink, Yi Yang, Cheng Liu, Cuiying Song, Mikhail Kovalev, Hongwei Ge, Fenghui Zhang, Xiaobin Zhang, Qiqi Xia, Haowei Peng, Gaobo Xi, Jun Mo, Shengyu Yan, Jianrong Shi, Jiangdan Li, Tuan Yi
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Paper 33 — arXiv:2504.18202
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Paper 33 — arXiv:2504.18202

The dynamical method provides an efficient way to discover post-common-envelope binaries (PCEB) with faint white dwarfs (WDs), thanks to the development of time-domain survey projects. We perform a comprehensive analysis of the PCEB system TMTS J15530469+4457458 (J1553), discovered by the Tsinghua University-Ma Huateng Telescopes for Survey, to explore its physical origin and evolutionary fate. This system is characterized by double-peaked Balmer emission lines, and a cross-correlation function is applied to derive its radial velocity (RV) from a series of phase-resolved Keck spectra. Analyses with the cross-correlation function suggest that this system is a single-lined spectroscopic binary and only one star is optically visible. Further analysis through Doppler tomography indicates that J1553 is a detached binary without an accretion disk. Under such a configuration, the simultaneous light-curve and RV fitting reveal that this system contains an unseen WD with mass $M_{\rm A}=0.56\pm 0.09\, M_{\odot}$, and an M4 dwarf with mass $M_{\rm B}=0.37\pm 0.02\,M_{\odot}$ and radius $R_{\rm B}=0.403^{+0.014}_{-0.015}\,R_{\odot}$. The extra prominent Balmer emission lines seen in the spectra can trace the motion of the WD, which are likely formed near the WD surface as a result of wind accretion. According to the MESA simulation, J1553 could have evolved from a binary consisting of a 2.0-4.0 ${M}_{\odot}$ zero-age-main-sequence star and an M dwarf with an initial orbital period $P_i\approx 201-476$ d, and the system has undergone a common-envelope (CE) phase. After about $3.3\times10^6$ yr, J1553 should evolve into a cataclysmic variable, with a transient state as a supersoft X-ray source at the beginning. J1553 is an excellent system for studying wind accretion, CE ejection physics, and binary evolution theory.

All other papers

Peter J. Barnes (1), Stuart D. Ryder (2 and 3), Giles Novak (4 and 5), Laura M. Fissel (6) ((1) Space Science Institute USA, (2) School of Mathematical and Physical Sciences Macquarie University Australia, (3) Astrophysics and Space Technologies Research Centre Macquarie University Australia, (4) Center for Interdisciplinary Exploration and Research in Astrophysics USA, (5) Northwestern University USA, (6) Queen's University Canada)

We present SOFIA/HAWC+ continuum polarisation data on the magnetic fields threading 17 pc-scale massive molecular clumps at the western end of the $\eta$ Car GMC (Region 9 of CHaMP, representing all stages of star formation from pre-stellar to dispersing via feedback), revealing important details about the field morphology and role in the gas structures of this clump sample. We performed Davis-Chandrasekhar-Fermi and Histogram of Relative Orientation analyses tracing column densities 25.0 $<$ log($N$/m$^{-2}$) $<$ 27.2. With HRO, magnetic fields change from mostly parallel to column density structures to mostly perpendicular at a threshold $N_{\rm crit}$ = (3.7$\pm$0.6)$\times$10$^{26}$ m$^{-2}$, indicating that gravitational forces exceed magnetic forces above this value. The same analysis in 10 individual clumps gives similar results, with the same clear trend in field alignments and a threshold $N_{\rm crit}$ = (1.9$^{+1.5}_{-0.8}$)$\times$10$^{26}$ m$^{-2}$. In the other 7 clumps, the alignment trend with $N$ is much flatter or even reversed, inconsistent with the usual HRO pattern. Instead, these clumps' fields reflect external environmental forces, such as from the nearby HII region NGC 3324. DCF analysis reveals field strengths somewhat higher than typical of nearby clouds, with the $Bn$ data lying mostly above the Crutcher (2012) relation. The mass:flux ratio $\lambda$ across all clumps has a gaussian distribution, with log$\lambda_{\rm DCF}$ = -0.75$\pm$0.45 (mean$\pm\sigma$): only small areas are dominated by gravity. However, a significant trend of rising log$\lambda$ with falling $T_{\rm dust}$ parallels Pitts et al's (2019) result: $T_{\rm dust}$ falls as $N_{\rm H_2}$ rises towards clump centres. Thus, in this massive clump sample, magnetic fields provide enough support against gravity to explain their overall low star formation rate.

Blakesley Burkhart, Thavisha E. Dharmawardena, Shmuel Bialy, Thomas J. Haworth, Fernando Cruz Aguirre, Young-Soo Jo, B-G Andersson, Haeun Chung, Jerry Edelstein, Isabelle Grenier, Erika T. Hamden, Wonyong Han, Keri Hoadley, Min-Young Lee, Kyoung-Wook Min, Thomas Müller, Kate Pattle, J. E. G. Peek, Geoff Pleiss, David Schiminovich, Kwang-Il Seon, Andrew Gordon Wilson, Catherine Zucker

this http URL Interactive view of the Eos cloud and its relationship to the Sun and Local bubble: this http URL

A longstanding prediction in interstellar theory posits that significant quantities of molecular gas, crucial for star formation, may be undetected due to being ``dark" in commonly used molecular gas tracers, such as carbon monoxide. We report the discovery of Eos, the closest dark molecular cloud, located just 94 parsecs from the Sun. This cloud is the first molecular cloud ever to be identified using H$_2$ far ultra-violet (FUV) fluorescent line emission, which traces molecular gas at the boundary layers of star-forming and supernova remnant regions. The cloud edge is outlined along the high-latitude side of the North Polar Spur, a prominent x-ray/radio structure. Our distance estimate utilizes 3D dust maps, the absorption of the soft X-ray background, and hot gas tracers such as O\,{\sc vi}; these place the cloud at a distance consistent with the Local Bubble's surface. Using high-latitude CO maps we note a small amount (M$_{\rm{H}_2}\approx$20-40\,M$_\odot$) of CO-bright cold molecular gas, in contrast with the much larger estimate of the cloud's true molecular mass (M$_{\rm{H}_2}\approx3.4\times 10^3$\,M$_\odot$), indicating most of the cloud is CO-dark. Combining observational data with novel analytical models and simulations, we predict this cloud will photoevaporate in 5.7 million years, placing key constraints on the role of stellar feedback in shaping the closest star-forming regions to the Sun.

We present a multi-method investigation of four metal-poor G-type main-sequence stars to resolve their Galactic origins. By combining high-resolution spectroscopy from PolarBase, photometric/astrometric data from Gaia DR3, and spectral energy distribution (SED) modelling, we derive precise stellar parameters, chemical abundances, kinematics and Galactic orbital parameters. The stars HD 22879, HD 144579, HD 188510, and HD 201891 show effective temperatures of 5855 +/- 110, 5300 +/- 160, 5370 +/- 60, and 5880 +/- 90 K; surface gravities of 4.40 +/- 0.18, 4.52 +/- 0.37, 4.57 +/- 0.13, and 4.48 +/- 0.18 (in cgs units); and metallicities of -0.86 +/- 0.08, -0.55 +/- 0.12, -1.60 +/- 0.07, and -1.15 +/- 0.07 dex, respectively. Kinematic analysis suggests that HD 22879, HD 144579, and HD 201891 are potential bulge-origin escapees, possibly ejected by the Galactic bar or spiral arm perturbations. HD 188510, however, shows halo-like dynamics, including a retrograde orbit. Chemical abundance trends ([alpha/Fe] vs. [Fe/H]) reveal mixed origins, challenging kinematic classifications. This discrepancy highlights the importance of integrative methodologies in Galactic archaeology. We associate HD 22879, HD 144579, and HD 201891 with the bulge globular clusters NGC 6441, NGC 5927, and NGC 6544, respectively. HD 188510's retrograde motion and low metallicity align with ejection from the halo globular cluster NGC 5139 (omega Centauri). These results illustrate the complex interplay of dynamical processes -- including bar resonances, spiral arm perturbations, and tidal stripping -- in depositing metal-poor stars into the solar neighborhood.

Samantha Scibelli, Andrés Megías, Izaskun Jiménez-Serra, Yancy Shirley, Jennifer Bergner, Judit Ferrer Asensio, Robin T. Garrod, Mélisse Bonfand, Anissa Pokorny-Yadav

Phosphorus is a key element that plays an essential role in biological processes important for living organisms on Earth. The origin and connection of phosphorus-bearing molecules to early Solar system objects and star-forming molecular clouds is therefore of great interest, yet there are limited observations throughout different stages of low-mass ($M < $ a few M$_\odot$) star formation. Observations from the Yebes 40 m and IRAM 30 m telescopes detect for the first time in the 7mm, 3mm, and 2mm bands multiple transitions of PN and PO, as well as a single transition of PO$^{+}$, toward a low-mass starless core. The presence of PN, PO and PO$^{+}$ is kinematically correlated with bright SiO(1-0) emission. Our results reveal not only that shocks are the main driver of releasing phosphorus from dust grains and into the gas-phase, but that the emission originates from gas not affiliated with the shock itself, but quiescent gas that has been shocked in the recent past. From radiative transfer calculations, the PO/PN abundance ratio is found to be $3.1^{+0.4}_{-0.6}$, consistent with other high-mass and low-mass star-forming regions. This first detection of PO$^{+}$ toward any low-mass star-forming region reveals a PO$^{+}$/PO ratio of $0.0115^{+0.0008}_{-0.0009}$, a factor of ten lower than previously determined from observations of a Galactic Center molecular cloud, suggesting its formation can occur under more standard Galactic cosmic-ray ionization rates. These results motivate the need for additional observations that can better disentangle the physical mechanisms and chemical drivers of this precursor of prebiotic chemistry.

Suryansh Saxena, Thomas J. Haworth, Blakesley Burkhart, Thavisha Dharmawardena, Edward Gillen, Kate Pattle, Janik Karoly, Erika Hamden

The Eos cloud, recently discovered in the far ultraviolet via H$_2$ fluorescence, is one of the nearest known dark molecular clouds to the Sun, with a distance spanning from $\sim94-136$pc. However, with a mass ($\sim5.5\times10^3$M$_\odot$) just under $40$ per cent that of star forming clouds like Taurus and evidence for net molecular dissociation, its evolutionary and star forming status is uncertain. We use Gaia data to investigate whether there is evidence for a young stellar population that may have formed from the Eos cloud. Comparing isochrones and pre-main sequence evolutionary models there is no clear young stellar population in the region. While there are a small number of $<10$Myr stars, that population is statistically indistinguishable from those in similar search volumes at other Galactic latitudes. We also find no unusual spatial or kinematic clustering toward the Eos cloud over distances $70-150$pc. Overall we conclude that the Eos cloud has most likely not undergone any recent substantial star formation, and further study of the dynamics of the cloud is required to determine whether it will do so in the future.

J. S. Thomsen, A. Miglio, K. Brogaard, J. Montalbán, M. Tailo, W. E. van Rossem, G. Casali, D. Jones, T. Arentoft, L. Casagrande, D. Sebastian, G. Buldgen, A. Triaud, M. Matteuzzi, A. Stokholm, M. N. Lund, B. Mosser, P. F. L. Maxted, J. Southworth, J. T. Gadeberg, N. Koivisto, Z. Gray, V. Pinter, K. Matilainen, A. A. Djupvik, J. Jessen-Hansen, F. Grundahl, D. Slumstrup, S. Frandsen

The study of resonant oscillation modes in low-mass red giant branch stars enables their ages to be inferred with exceptional ($\sim$10%) precision, unlocking the possibility to reconstruct the temporal evolution of the Milky Way at early cosmic times. Ensuring the accuracy of such a precise age scale is a fundamental yet difficult challenge. Since the age of red giant branch stars primarily hinges on their mass, an independent mass determination for an oscillating red giant star provides the means for such assessment. We analyze the old eclipsing binary KIC10001167, which hosts an oscillating red giant branch star and is a member of the thick disk of the Milky Way. Of the known red giants in eclipsing binaries, this is the only member of the thick disk that has asteroseismic signal of high enough quality to test the seismic mass inference at the 2% level. We measure the binary orbit and obtain fundamental stellar parameters through combined analysis of light curve eclipses and radial velocities, and perform a detailed asteroseismic, photospheric, and Galactic kinematic characterization of the red giant and binary system. We show that the dynamically determined mass $0.9337\pm0.0077 \rm\ M_{\odot}$ (0.8%) of this 10 Gyr-old star agrees within 1.4% with the mass inferred from detailed modelling of individual pulsation mode frequencies (1.6%). This is now the only thick disk stellar system, hosting a red giant, where the mass has been determined both asteroseismically with better than 2% precision, and through a model-independent method at 1% precision, and we hereby affirm the potential of asteroseismology to define an accurate age scale for ancient stars to trace the Milky Way assembly history.

Janik Karoly, Kate Pattle, Blakesley Burkhart, Thavisha Dharmawardena, B.-G. Andersson, Thomas J. Haworth

The recently-discovered Eos molecular cloud, is a CO-dark, low-density cloud located at a distance of approximately 94 pc from the Sun which does not appear to have formed stars at any point in its history. In this paper we investigate the magnetic fields in the Eos cloud, near the interface between the atomic Cold Neutral Medium (CNM) and molecular gas, using dust emission and extinction polarimetry. A Histogram of Relative Orientation analysis shows that the magnetic field is preferentially parallel to the density structure of the cloud, while a Davis-Chandrasekhar-Fermi analysis finds magnetic field strengths of 8$\pm$4 $\mu$G across the Eos cloud and 12$\pm$4 $\mu$G in the somewhat denser MBM 40 sub-region. These results are consistent with a previous estimate of magnetic field strength in the Local Bubble and suggest that the fields in the Eos cloud are dynamically important compared to both gravity and turbulence. Our findings are fully consistent with the expected behavior of magnetized, non-self-gravitating gas near the CNM/molecular cloud boundary.

There is a clear dearth of very eccentric binaries among those for which individual eccentricities can be measured. In this paper we report on observations of the two nearby, bright and very eccentric visual binaries Zeta Boötis ($\zeta$ Boo) and Eta Ophiuchi ($\eta$ Oph), for which VLTI/GRAVITY interferometric observations were obtained during their pericenter passages in 2023/4. Previous observations of $\zeta$ Boo suggest an eccentricity $e>0.99$ with high significance, implying that it has the highest eccentricity of any known binary. However, our interferometric measurements near periastron passage reveal that the eccentricity is actually $e=0.980450\pm0.000064$ (second highest well constrained eccentricity) with a pericenter distance $a_p=0.818\pm0.009\text{ au}$. We attribute the previous over-estimation to a degeneracy that plagues very eccentric visual binary orbital solutions. For $\eta$ Oph we find an eccentricity $e=0.93077\pm0.00013$ (compared to previous estimates of $e=0.95\pm 0.02$), a pericenter distance $a_p=2.15\pm0.10 \text{ au}$ and attribute the over-estimated dynamical mass in the previous solution to an underestimated error in the semi-major axis. In both systems full circularization is expected as the stars evolve and expand, ultimately leading to close binaries with no memory of their very eccentric past.

Jack E. Birkin, Justin S. Spilker, Rodrigo Herrera-Camus, Rebecca L. Davies, Lilian L. Lee, Manuel Aravena, Roberto J. Assef, Loreto Barcos-Muñoz, Alberto Bolatto, Tanio Diaz-Santos, Andreas L. Faisst, Andrea Ferrara, Deanne B. Fisher, Jorge González-López, Ryota Ikeda, Kirsten Knudsen, Juno Li, Yuan Li, Ilse de Looze, Dieter Lutz, Ikki Mitsuhashi, Ana Posses, Monica Relaño, Manuel Solimano, Ken-ichi Tadaki, Vicente Villanueva

There is a broad consensus from theory that stellar feedback in galaxies at high redshifts is essential to their evolution, alongside conflicting evidence in the observational literature about its prevalence and efficacy. To this end, we utilize deep, high-resolution [CII] emission line data taken as part of the [CII] resolved ISM in star-forming galaxies with ALMA (CRISTAL) survey. Excluding sources with kinematic evidence for gravitational interactions, we perform a rigorous stacking analysis of the remaining 15 galaxies to search for broad emission features that are too weak to detect in the individual spectra, finding only weak evidence that a broad component is needed to explain the composite spectrum. Additionally, such evidence is mostly driven by CRISTAL-02, which is already known to exhibit strong outflows in multiple ISM phases. Interpreting modest residuals in the stack at $v\sim300$kms$^{-1}$ as an outflow, we derive a mass outflow rate of $\dot{M}_{\rm out}=26\pm11$M$_\odot$yr$^{-1}$ and a cold outflow mass-loading factor of $\eta_m=0.49\pm0.20$. This result holds for the subsample with the highest star-formation rate surface density $(\Sigma_{\rm{SFR}}>1.93$M$_\odot$yr$^{-1}$kpc$^{-2}$) but no such broad component is present in the composite of the lower-star-formation rate density subsample. Our results imply that the process of star-formation-driven feedback may already be in place in typical galaxies at $z=5$, but on average not strong enough to completely quench ongoing star formation.

Tom Wagg, Julianne J. Dalcanton, Mathieu Renzo, Katelyn Breivik, Matthew E. Orr, Adrian M. Price-Whelan, Akaxia Cruz, Alyson Brooks, Ulrich P. Steinwandel, Eric C. Bellm

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Core-collapse supernova feedback models in hydrodynamical simulations typically assume that all stars evolve as single stars. However, the majority of massive stars are formed in binaries and multiple systems, where interactions with a companion can affect stars' subsequent evolution and kinematics. We assess the impact of binary interactions on the timing and spatial distribution of core-collapse supernovae, using `cogsworth` simulations to evolve binary star populations, and their subsequent galactic orbits, within state-of-the-art hydrodynamical zoom-in galaxy simulations. We show that binary interactions: (a) displace supernovae, with ~13% of all supernovae occurring more than 0.1 kpc from their parent cluster; and (b) produce delayed supernovae, such that ~25% of all supernovae occur after the final supernova from a single star population. Delays are largest for low-mass merger products, which can explode more than 200 Myr after a star formation event. We characterize our results as a function of: (1) initial binary population distributions, (2) binary physics parameters and evolutionary pathways, (3) birth cluster dissolution assumptions, and (4) galaxy models (which vary metallicity, star formation history, gravitational potential and simulation codes), and show that the overall timing and spatial distributions of supernovae are surprisingly insensitive to most of these variations. We provide metallicity-dependent analytic fits that can be substituted for single-star subgrid feedback prescriptions in hydrodynamical simulations, and discuss some of the possible implications for binary-driven feedback in galaxies, which may become particularly important at high redshift.

Context. The 1.8 MeV gamma-rays corresponding to the decay of the radioactive isotope Al-26 (with a half-life of 0.72 Myr) have been observed by the SPI detector on the INTEGRAL spacecraft and extensively used as a tracer of star formation and current nucleosynthetic activity in the Milky Way Galaxy. Further information is encoded in the observation related to the higher Al-26 content found in regions of the Galaxy with the highest line-of-sight (LoS) velocity relative to an observer located in the Solar System. However, this feature remains unexplained. Aims. We ran a cosmological "zoom-in" chemodynamical simulation of a Milky Way-type galaxy, including the production and decays of radioactive nuclei in a fully self-consistent way. We then analyzed the results to follow the evolution of Al-26 throughout the lifetime of the simulated galaxy to provide a new method for interpreting the Al-26 observations. Methods. We included the massive star sources of Al-26 in the Galaxy and its radioactive decay into a state-of-the-art galactic chemical evolution model, coupled with cosmological growth and hydrodynamics. This approach allowed us to follow the spatial and temporal evolution of the Al-26 content in the simulated galaxy. Results. Our results are in agreement with the observations with respect to the fact that gas particles in the simulation with relatively higher Al-26 content also have the highest LoS velocities. On the other hand, gas particles with relatively lower Al-26 content (i.e., not bright enough to be observed) generally display the lowest LoS velocities. However, this result is not conclusive because the overall rotational velocity of our simulated galaxy is higher than that observed for cold CO gas in the Milky Way Galaxy. Furthermore, we found no significant correlation between gas temperature, rotational velocity, and Al-26 content at any given radius. We also [...]

Abhishek Rajhans, Mitsuo Oka, Marit Øieroset, Tai Phan, Ian J. Cohen, Stephen A. Fuselier, Drew L. Turner, James L. Burch, Christopher T. Russell, Christine Gabrielse, Daniel J. Gershman, Roy B. Torbert

Magnetic reconnection is an explosive energy release event. It plays an important role in accelerating particles to high non-thermal energies. These particles often exhibit energy spectra characterized by a power-law distribution. However, the partitioning of energy between thermal and non-thermal components, and between ions and electrons, remains unclear. This study provides estimates of energy partition based on a statistical analysis of magnetic reconnection events in Earth's magnetotail using data from the Magnetospheric Multiscale (MMS) mission. Ions are up to ten times more energetic than electrons but have softer spectra. We found for both ions and electrons that, as the average energy of particles (temperature) increases, their energy spectra become \textit{softer} (steeper) and thus, the fraction of energy carried by the non-thermal components decreases. These results challenge existing theories of particle acceleration through magnetotail reconnection.

Annu Bura, Tanmoy Samanta, Avijeet Prasad, Ronald L. Moore, Alphonse C. Sterling, Vasyl Yurchyshyn, Arun Surya

Recurrent chromospheric fan-shaped jets highlight the highly dynamic nature of the solar atmosphere. They have been named as ''light walls'' or ''peacock jets'' in high-resolution observations. In this study, we examined the underlying mechanisms responsible for the generation of recurrent chromospheric fan-shaped jets utilizing data from the Goode Solar Telescope (GST) at Big Bear Solar Observatory, along with data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamic Observatory (SDO). These jets appear as dark elongated structures in H$\alpha$ wing images, persist for over an hour, and are located in the intergranular lanes between a pair of same-polarity sunspots. Our analysis reveals that magnetic flux cancellation at the jet base plays a crucial role in their formation. HMI line-of-sight magnetograms show a gradual decrease in opposite-polarity fluxes spanning the sequence of jets in H$\alpha$ - 0.8 angstrom images, suggesting that recurrent magnetic reconnection, likely driven by recurrent miniature flux-rope eruptions that are built up and triggered by flux cancellation, powers these jets. Additionally, magnetic field extrapolations reveal a 3D magnetic null-point topology at the jet formation site $\sim$1.25 Mm height. Furthermore, we observed strong brightening in AIA 304 angstrom channel above the neutral line. Based on our observations and extrapolation results, we propose that these recurrent chromospheric fan-shaped jets align with the minifilament eruption model previously proposed for coronal jets. Though our study focuses on fan-shaped jets in between same-polarity sunspots, similar mechanism might be responsible for light bridge-associated fan-shaped jets.

Anan Lu, Daryl Haggard, Martin Bureau, Jindra Gensior, Carmelle Robert, Thomas G. Williams, Fu-Heng Liang, Woorak Choi, Timothy A. Davis, Ilaria Ruffa, Sara Babic, Hope Boyce, Michele Cappellari, Benjamin Cheung, Laurent Drissen, Jacob S. Elford, Thomas Martin, Carter Rhea, Laurie Rousseau-Nepton, Marc Sarzi, Hengyue Zhang

Early-type galaxies (ETGs) are known to harbour dense spheroids of stars with scarce star formation (SF). Approximately a quarter of these galaxies have rich molecular gas reservoirs yet do not form stars efficiently. These gas-rich ETGs have properties similar to those of bulges at the centres of spiral galaxies. We use spatially-resolved observations (~ 100 pc resolution) of warm ionised-gas emission lines (Hbeta, [O III], [N II], Halpha and [S II]) from the imaging Fourier transform spectrograph SITELLE at the Canada-France-Hawaii Telescope and cold molecular gas (12CO(2-1) or 12CO(3-2)) from the Atacama Large Millimeter/submillimeter Array (ALMA) to study the SF properties of 8 ETGs and bulges. We use the ionised-gas emission lines to classify the ionisation mechanisms and demonstrate a complete absence of regions dominated by SF ionisation in these ETGs and bulges, despite abundant cold molecular gas. The ionisation classifications also show that our ETGs and bulges are dominated by old stellar populations. We use the molecular gas surface densities and Halpha-derived SF rates (in spiral galaxies outside of the bulges) or upper limits (in ETGs and bulges) to constrain the depletion times (inverse of the SF efficiencies), suggesting again suppressed SF in our ETGs and bulges. Finally, we use the molecular gas velocity fields to measure the gas kinematics, and show that bulge dynamics, particularly the strong shear due to the deep and steep gravitational potential wells, is an important SF-regulation mechanism for at least half of our sample galaxies.

Aurora Aguayo, Claudio Caceres, Zhen Guo, Matthias R. Schreiber, Álvaro Ribas, Joel H. Kastner, Lucas A. Cieza, Sebastián Pérez, Héctor Cánovas, Daniela Rojas Bozza, D. Annie Dickson-Vandervelde, William Grimble, Alejandro Santamaría-Miranda

Young stellar objects (YSOs) are surrounded by protoplanetary disks, which are the birthplace of young planets. Ring and gap structures are observed among evolved protoplanetary disks, often interpreted as a consequence of planet formation. The pre-Main Sequence (pre-MS) star MP Mus hosts one of the few known examples of protoplanetary disks within ~100 pc. Previously, a disk ring structure, with a radius of 80-85 au, was detected in scattered light via near-infrared coronographic/polarimetric imaging. This ring structure may be indicative of the disk clearing process. Although such ring structures were not seen in the ALMA Band 6 images, some features were detected at $\sim$50 au. In this paper, we analyzed new ALMA Band 7 observations of MP Mus in order to investigate the details of its disk substructures. By subtracting the continuum profile generated from Band 7 data, we discovered a ring structure in the Band 7 dust continuum image at $\sim$50 au. We calculated the overall dust mass as $28.4\pm2.8 M_{\oplus}$ at 0.89 mm and $26.3\pm2.6 M_{\oplus}$ at 1.3 mm and the millimeter spectral index $\alpha_{0.89-1.3mm} \sim 2.2 \pm 0.3$ between 0.89 mm and 1.3 mm. Moreover, we display the spatial distribution of the spectral index ($\alpha_{mm}$), estimating values ranging from 1.3 at the inner disk to 4.0 at a large radius. Additionally, we observed an extended gas disk up to $\sim$120 au, in contrast with a compact continuum millimeter extent of $\sim$60 au. We conclude that there are strong indicators for an active radial drift process within the disk. However, we cannot discard the possibility of a dust evolution process and a grain growth process as responsible for the outer disk structures observed in the ALMA continuum imaging.

Robert Jedicke, Elisa Maria Alessi, Naja Wiedner, Mehul Ghosal, Edward B. Bierhaus, Mikael Granvik

This work examines the plausibility of a lunar origin of natural objects that have a negative total energy (ET) with respect to the geocenter while within 3 Earth Hill radii (RH), a population that we will refer to as 'bound'. They are a super-set of the population of 'minimoons' which require that the object make at least one orbit around Earth in a synodic frame rotating with Earth and that its geocentric distance be <RH at some point while ET<0. Only two minimoons have been discovered to date, 2006 RH120 and 2020 CD3, while 2024 PT5 and 2022 NX1 meet our condition for 'bound'. The likely source region of co-orbital objects is either the main belt, lunar ejecta, or a combination of both. Earlier works found that dynamical evolution of asteroids from the MB could explain the observed minimoon population, but spectra of 2020 CD3 and 2024 PT5 and Earth co-orbital (469219) Kamo'oalewa are more consistent with lunar basalts than any MB asteroid spectra. This work calculates the steady-state size-frequency distribution of the bound population given our understanding of the lunar impact rate, the energy of the impactors, crater-scaling relations, and the relationship between the ejecta mass and speed. We integrate the trajectory of lunar ejecta and calculate the statistics of 'prompt' bounding that take place immediately after ejection, and 'delayed' bounding that occurs after the objects have spent time on heliocentric orbits. A sub-set of the delayed bound population composes the minimoon population. We find that lunar ejecta can account for the observed population of bound objects but uncertainties in the crater formation and lunar ejecta properties induce a many orders of magnitude range on the predicted population. If the bound objects can be distinguished as lunar or asteroidal based on their spectra it may be possible to constrain crater formation processes.

We investigate the impact of inhomogeneous inflaton perturbations on primordial magnetic fields within the framework of generalized inflationary magnetogenesis models. Extending the Ratra model to general spacetime backgrounds, we analyze the constraint structure of the electromagnetic field and demonstrate that the standard Coulomb gauge must be generalized to accommodate spatial inhomogeneities. Instead of the vector potential, we solve the conjugate momentum with the modified initial conditions introduced by the coupling function, which become dominant during the late stages of inflation. These change the conditions under which scale-invariant electromagnetic spectra are achieved. Furthermore, we address the challenge of evaluating convolutions between vector potentials and inflaton perturbations by employing separate large- and small-scale approximations. The resulting influence to the electric and magnetic power spectra are quantified using $\Delta_E$ and $\Delta_B$, revealing a scale-dependent influence of inhomogeneities. We also find that the spectrum index evolution is sensitive to the sign of $V_{\phi}$, with distinctive behaviors for electric and magnetic fields under different scale-invariance conditions. Notably, for nearly scale-invariant magnetic fields, the perturbative effects shift the spectral index towards the red and migrate toward smaller scales as inflation progresses, offering a potential observational probe to differentiate between large-field and small-field inflation scenarios.

The equivalence of the Jordan and Einstein frames has been a subject of considerable interest in the field. In this paper, within the context of $f(R)$ gravity, we explore the inflationary magnetogenesis model, focusing on the magnetic field energy density and its spectrum in both the Jordan and Einstein frames to elucidate the equivalence between these two reference frames. Our analysis reveals that during the inflationary epoch, while the magnetic field exhibits a scale-invariant spectrum in the Einstein frame, it demonstrates a blue spectrum in the Jordan frame. Additionally, we investigate the post-inflationary evolution of the magnetic field's energy density in both frames, uncovering that for scale-invariant spectra in the Einstein frame during inflation, the magnetic field transitions to a blue spectrum, whereas in the Jordan frame, it evolves into a red spectrum. We also establish the conditions under which both frames may exhibit scale-invariant spectra simultaneously during the inflationary period.

Recent ALMA observations of the [OIII] 88 $\mu$m line provide spectroscopic confirmation of two JWST photometric candidates, GS-z14 and GHZ2, at $z=14.2$ and $z=12.3$, respectively. These discoveries reveal that star formation and chemical enrichment were already underway when the universe was merely 300 Myr old, posing a challenge to galaxy formation models. Here we construct post-processed models for the [OIII] emission lines from galaxies in the state-of-the-art FIRE and IllustrisTNG simulations. Neither simulation suite contains galaxies directly comparable to GS-z14 or GHZ2. However, one simulated FIRE galaxy closely resembles GS-z14 in its star formation rate (SFR), stellar mass, metallicity, [OIII] luminosity and line-width, albeit at $z=8.7$, lagging GS-z14's formation by roughly 300 Myr. Although further investigation is required, we argue that the lack of simulated galaxies matching GS-z14 and GHZ2 may largely be a consequence of the limited volume of the FIRE simulations and the limited mass resolution of Illustris-TNG. We quantify the prospects for follow-up spectroscopic detections of GS-z14 in the [OIII] 52 $\mu$m line with ALMA, and in rest-frame optical [OIII] and Balmer lines with the MIRI instrument on JWST.

Using over 170,000 red clump stars selected from LAMOST and APOGEE, we conduct a detailed analysis of the stellar $V_{Z}$ as a function of $L_{Z}$ (or $R_{g}$) across different $\phi$ bins for various disk populations. The $V_{Z}$ of the whole RC sample stars exhibits a wave-like pattern superimposed on an exponentially increasing trend, indicating the contribution from disk warp, disk flare and disk waves. Our results across various populations suggest that the thin disk is similar to the whole RC sample behavior, while the thick disk displays a wave-like pattern superimposed on a linearly increasing trend, meaning that the features of disk warp and waves are present in both thin and thick disks, and the disk flare feature is only present in the thin disk. These results indicate that the disk warp is potentially driven by secular processes like disk perturbations from intergalactic magnetic fields and a misaligned dark halo. The line-of-node (LON) of the disk warp of various populations displays a slight difference, with $\phi_{0}$ = 5.68 $\pm$ 2.91 degree for the whole RC sample stars, $\phi_{0}$ = 5.78 $\pm$ 2.89 degree for the thin disk stars, and $\phi_{0}$ = 4.10 $\pm$ 3.43 degree for the thick disk stars.

In this study, we investigate the morphology of galaxies in the TNG100 simulation by applying mock observation techniques and compare the results with the observational data from the Sloan Digital Sky Survey (SDSS). By employing a hierarchical Convolutional Neural Network (CNN) approach, we classify galaxies into four morphological categories (Ellipticals, S0/a, Sab/Sb, and Sc/Sd/Irregulars). Our findings show that the morphological characteristics of the mock-observed galaxy samples closely match those observed in the SDSS, successfully reproducing key features such as distinct parameter distributions for different types. However, some discrepancies are identified: notably, a significant lack of early-type galaxies (ETGs) in the dwarf galaxy regime ($M_* < 10^{10} M_{\odot}$) and minimal distinction between Sab/Sb and Sc/Sd/Irregular galaxies in the mock-observed samples, unlike the clear differences seen in actual observations. These divergences may stem from simulation properties such as elevated star formation efficiency at low mass end or resolution limits. Observational effects, including the impact of the Point Spread Function, sky background, and instrumental noise, can independently cause approximately 7.87\% morphological misclassifications by our CNN model. Compared to previous studies using gravity-based definitions of galaxies that failed to clearly distinguish the parameter distributions of ETGs versus Late-Type Galaxies, our brightness-based sample definition method better recovers the observed morphological parameter distributions, especially their distinct differences. Our study underscores that, alongside mock observations, employing galaxy segmentation methods consistent with observational practices is crucial for appropriately recovering realistic morphological parameters from simulations and enabling fair comparisons.

The dynamical evolution of long-period comets (LPCs) and their meteoroid streams is usually described with the Sun as the primary body, but over most of their orbits the Solar System barycenter (SSB) is effectively the orbital focus. Detailed numerical integrations show that the orbital elements in the barycentric reference frame are nearly constant, except within the orbit of Jupiter where the comet or meteoroid shifts to a heliocentric orbit. Here we show that this encounter can be modeled in the barycentric frame analogously to how planetary close encounters are treated in the heliocentric frame, with the comet captured into an elliptic orbit about the Sun as it in turn orbits SSB. Modeling the encounters as a two-body interaction in the SSB frame gives a different insight into the dynamics than offered by secular perturbation analyses, and reveals that a large portion of the stochasticity seen in the evolution of the comet's orbit is due to the Sun's state relative to SSB at the time of encounter. LPCs sample the Sun's state randomly at each return, so that a statistical characterization of Sun's state is sufficient to determine the qualitative evolution of their orbits, including stream dispersion. The barycentric orbital elements are shown to execute random walks well-characterized by Maxwellian distributions. This is superimposed atop a systematic orbital precession induced by planetary torques. Planetary close encounters add a second stochastic component, but this component does not typically dominate the solar perturbations. Based on the statistics of Sun's state alone, the age of a long-period comet meteoroid stream in a given orbit can be derived to reasonable precision from the observed random dispersion of the angular orbital elements at Earth.

Vaibhav Kumar Pandey, Arvind K Dattatrey, Apara Tripathi, R K S Yadav, Shantanu Rastogi

This study presents photometric analysis of the intermediate-age open cluster King 6, utilizing photometric data in UBV(RI)$_c$ passband and data from the 2MASS mission. The Gaia DR3 kinematic data were used to estimate the membership probabilities and TESS data is employed to search for variable stars within the cluster. The cluster's radius is estimated to be 9$^\prime$.0 based on the stellar density profile, while optical and near-infrared color-color diagrams} revealed color excesses of E(B-V) = 0.58$ \pm$ 0.03, E(J-K) = 0.24 $\pm$ 0.03, and E(V-K) = 1.53 $\pm$ 0.01 mag. Interstellar extinction law is normal in the direction of the cluster. The cluster$^\prime$s estimated age is $\sim$251 Myr and distance is 724 $\pm$ 5 pc. The mass function slope was found to be x = 0.57 $\pm$ 0.28 by considering stars $\geq$ 1 M$_\odot$. Our analysis indicates that the cluster is dynamically relaxed. Furthermore, we identified three new variable stars for the first time in the cluster region using TESS data. These variables belong to the category of slow pulsating B-type variables, with periods of 46.70, 47.92, and 37.56 hours.

B. L. Alterman, Y. J. Rivera, S. T. Lepri, J. M. Raines, R. D'Amicis

When observed at 1 AU, slow solar wind is typically considered to have originated in source regions with magnetic topologies that are intermittently open to the heliosphere. Fast wind is typically considered to have originated in source regions that are continuously open to the heliosphere eg coronal holes. The evolution of the solar wind helium abundance (AHe) with solar activity is likely driven by the evolution of different solar wind source regions. Separating the solar wind into fast and slow for each element based on its characteristic speed derived in Alterman et al. (2025) we quantify the evolution of helium and heavy element abundances $(X/H):(X/H)_\mathrm{photo}$ with solar activity. We show that AHe strongly correlates with sunspot number; in slow and fast wind the average non-transient solar wind AHe is limited to 51% of its photospheric value; slow wind heavy element abundances evolve significantly with solar activity; fast wind heavy element abundances do not; the correlation coefficient with sunspot number of elemental abundances for species heavier than He monotonically increases with increasing mass; and the correlation coefficients between the in situ observations and the normalized sunspot number are stronger than those using the unnormalized sunspot number. We infer that the sunspot number is a clock timing the solar cycle but not the driver of the physical process underlying the evolution of these abundances with solar activity; this underlying process is likely related to the energy available to accelerate the solar plasma from the chromosphere and transition region or low corona into the solar wind; and differences between the evolution of slow and fast solar wind abundances are similarly related to the energy available to accelerate the elements at these heights above the Suns surface.

Musheng Lin, Ya Wang, Liheng Yang, Jie Chen, Wenwei Pan, Shuyue Li, Qingmin Zhang

In this article, we report the multiwavelength and multiview observations of transverse oscillations of two loop strands induced by a jet-related, confined flare in active region NOAA 13056 on 11 July 2022. The jet originates close to the right footpoint of the loops and propagates in the northeast direction. The average rise time and fall time of the jet are $\approx$ 11 and $\approx$ 13.5 minutes, so that the lifetime of the jet reaches $\approx$ 24.5 minutes. The rising motion of the jet is divided into two phases with average velocities of $\approx$ 164 and $\approx$ 546\,km\,s$^{-1}$. The falling motion of the jet is coherent with an average velocity of $\approx$ 124\,km\,s$^{-1}$. The transverse oscillations of the loops, lasting for 3 $-$ 5 cycles, are of fundamental standing kink mode. The maximal initial amplitudes of the two strands are $\approx$ 5.8 and $\approx$ 4.9 Mm. The average periods are $\approx$ 405\,s and $\approx$ 407\,s. Both of the strands experience slow expansions during oscillations. The lower limits of the kink speed are 895$_{-17}^{+21}$\,km\,s$^{-1}$ for loop\_1 and 891$_{-35}^{+29}$\,km\,s$^{-1}$ for loop\_2, respectively. The corresponding lower limits of the Alfvén speed are estimated to be 664$_{-13}^{+16}$\,km\,s$^{-1}$ and 661$_{-26}^{+22}$\,km\,s$^{-1}$.

S. Maitrey, Liton Majumdar, Varun Manilal, Baibhav Srivastava, Prathap Rayalacheruvu, Karen Willacy, Eric Herbst

Cold dense cores are unique among the structures found in the interstellar medium (ISM), as they harbor a rich chemical inventory, including complex organic molecules (COMs), which will be inherited by future evolutionary stages. These molecules exist both in the gas phase and as ices accreted onto grain surfaces. To model these environments, we present Pegasis, a new, fast, and extensible three-phase astrochemical code to explore the chemistry of cold cores, with an emphasis on the role of diffusive and non-diffusive chemistry in shaping their gas and grain chemical compositions. We incorporated the 2024 KIDA chemical network and compared our results with current astrochemical models. Using a traditional rate-equation-based approach, we implemented both diffusive and non-diffusive chemistry, coupled with either an inert or chemically active ice mantle. We identify crucial reactions that enhance the production of COMs through non-diffusive mechanisms on the grain surface as well as the mechanisms through which they can accumulate in the gas phase. Across all models with non-diffusive chemistry, we observe a definite enhancement in the concentration of COMs on both the grain surface as well as in the grain mantle. Finally, our model broadly reproduces the observed abundances of multiple gas-phase species in the cold dense core TMC-1 (CP) and provides insights into its chemical age. Our work demonstrates the capabilities of Pegasis in exploring a wide range of grain-surface chemical processes and modeling approaches for three-phase chemistry in the ISM, providing robust explanations for observed abundances in TMC-1 (CP). In particular, it highlights the role of non-diffusive chemistry in the production of gas-phase COMs on grain surfaces, which are subsequently chemically desorbed, especially when the precursors involved in their formation on the surfaces are heavier than atomic hydrogen.

The discovery of supermassive black holes (SMBHs) at high redshifts has intensified efforts to understand their early formation and rapid growth during the cosmic dawn. Using a semi-analytical cosmological framework, we investigate the role of tidal disruption events (TDEs) involving Population III (Pop-III) stars in driving the growth of heavy seed black holes (10^4-10^6 solar mass). Our results indicate that Pop-III TDEs significantly accelerate the growth of relatively lighter massive black holes (~ 10^4-10^5 solar mass), allowing them to increase their mass by roughly an order of magnitude within the first 10 Myr. Cosmological evolution modeling further supports that such Pop-III TDE-driven growth scenarios are consistent with the formation pathways of observed luminous high-redshift quasars originating from seed black holes at 10<z<15. We also discuss the future observational probes of these early-stage growth processes that future facilities, including space-based gravitational wave observatories and infrared telescopes like JWST, could potentially detect. These findings provide a clear observational framework to test the critical role of Pop-III star interactions in the rapid buildup of SMBHs during the earliest epochs.

One of the potential sources of repeating Fast Radio Bursts (FRBs) is a rotating magnetosphere of a compact object, as suggested by the similarities in the polarization properties of FRBs and radio pulsars. Attempts to measure an underlying period in the times of arrival of repeating FRBs have nevertheless been unsuccessful. To explain this lack of observed periodicity, it is often suggested that the line of sight towards the source must be sampling active parts of the emitting magnetosphere throughout the rotation of the compact object, i.e. has a large duty cycle, as can be the case in a neutron star with near-aligned magnetic and rotation axes. This may lead to apparently aperiodic bursts, however the polarization angle of the bursts should be tied to the rotational phase from which they occur. This is true for radio pulsars. We therefore propose a new test to identify a possible stable rotation period under the assumptions above, based on a periodogram of the measured polarization angle timeseries for repeating FRBs. We show that this test is highly sensitive when the duty cycle is large, where standard time-of-arrival periodicity searches fail. Therefore, we can directly test the hypothesis of repeating FRBs of magnetospheric origin with a stable rotation period. Both positive and negative results of the test applied to FRB data will provide important information.

In this paper I will describe a new software package developed using the Java programming language, aimed to compute the positions of any Solar System body (among asteroids, comets, planets, and satellites) to help to perform cross-matches of them in observations taken from earth- and space-based observatories. The space telescopes supported are Hubble, James Webb, Euclid, XMM-Newton, Spitzer, Herschel, Gaia, Kepler, Chandra, and TESS, although the flexibility of the software allows to support any other mission without the need to change a single line of code. The orbital elements can be selected among the asteroid database from the Lowell observatory (completed with the cometpro database of comets maintained by the LTE), and the JPL database of minor bodies. The software does not depend on external tools, and performs its own numerical integration of minor bodies. The dynamical model implemented for the Solar System includes the gravity effects of all major bodies, including the Earth, Moon, and Pluto as individual bodies, 16 perturbing asteroids as in other tools, the General Relativity effects, the oblateness of the Sun, Earth, and Moon, and the non-gravitational forces for both comets and asteroids. A complete set of web services allow to compute the cross-matches (that are later to be confirmed, for instance by visual inspection of the images) and also ephemerides of specific bodies. The code is highly optimized and follows the highest standards in terms of software quality and documentation.

Jie Tian, Yinghe Zhao, Xiejin Li, Jinming Bai

The study of morphology in galaxies offers a convenient and quantitative method to measure the shapes and characteristics of galaxy light distribution that reflect the evolutionary history. For AGN-host dwarf galaxies, however, there is a lack of detailed studies on their morphologies. In this work, we compile a relatively large sample ($\sim$400 members) of local AGN-host dwarf ($M_{\star}\leq10^{9.5} M_{\odot}$ and $z<0.055$) galaxies selected via various methods. We use the $grz$ bands images from DESI DR10 and the Python package statmorph to measure non-parametric coefficients. We also carry out visual inspection with the assistance of deep learning to classify these galaxies into early-type (ETGs), late-type (LTGs) galaxies, and mergers, and find that about 37%, 44%, and 13% of the total sample sources are ETGs, LTGs, and mergers, respectively. In comparison to normal dwarf galaxies, AGN-host dwarfs have a higher probability to be LTGs, and a lower merger rate, indicating that mergers/interactions are not the primary driver of AGN activities. Among the subsamples selected with different methods, the BPT sample has the highest fraction of ETGs, the variability sample consists of the largest fraction of LTGs, and the mid-IR sample contains the most mergers.

D. Williams-Baldwin (1), T. W. B. Muxlow (1), G. Lucatelli (1), R. J. Beswick (1) ((1) Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK)

Ultra-luminous X-ray sources (ULXs) are X-ray bright (L$_{\rm X-ray} >$3$\times$10$^{39}$erg s$^{-1}$) extra-galactic objects that are powered by either neutron stars, or stellar or intermediate-mass black holes (IMBHs) but few have been detected in the radio waveband. In the nearby galaxy M82, the brightest ULX - M82 X$-$1, is thought to be associated with an IMBH but to date does not have a radio counterpart. We present deep wide-band reprocessed e-MERLIN images observed in 2015 May with an r.m.s. sensitivity of 7$\mu$Jy beam$^{-1}$ and report the discovery of a new radio source with an integrated flux of S$_{\rm \nu=4.88\,GHz}$ = 174$\pm$15$\mu$Jy, which is spatially co-incident with the Chandra X-ray position of M82 X$-$1. This source is not detected in archival MERLIN/e-MERLIN observations in the last three decades. A search for intra-observation variability in the 2015 e-MERLIN data was inconclusive, but a comparison with 1.5 GHz e-MERLIN observations taken a week prior yielded no detection. We also detect the source at the same position with milliarcsecond angular resolution in EVN+e-MERLIN data from 2021 March at 53$\pm$10$\mu$Jy. The radio source position is ICRF J2000 RA: 09$^{h}$55$^{m}$50.1172$^{s}$, Dec: +69$^{\circ}$40'46.606" ($\pm$1.5 mas). These radio fluxes are consistent with other radio-detected ULXs on the radio:X-ray plane and points towards a stellar/intermediate-mass black hole. The black hole mass inferred by the `fundamental plane of black hole activity' is 2650 M$_{\odot}$, but this value remains highly uncertain.

Uranus and Neptune, the so-called "ice giants", represent a fascinating class of planets. They are the outermost planets in the solar system with intermediate masses/sizes, complex non-polar magnetic fields, strong atmospheric winds, and not well-understood internal structures. Studying the interiors of Uranus and Neptune is vital for advancing our understanding of planetary formation and evolution as well as for the characterization of planets around other stars. In this review, we summarize our current knowledge of the interior and formation of Uranus and Neptune. Both planets are expected to be composed of rocks and ices and have H-He atmospheres of the order of 10% of their total masses. The rock-to-water ratios in Uranus and Neptune, however, are very uncertain. It is also unclear how the different materials are distributed within the interiors and whether distinct layers exist. While often Uranus and Neptune are viewed as being "twin planets" it is in fact unclear how different the two planets are from each other, and whether they are indeed "icy" (water-dominated) planets. After summarizing the current-knowledge of the interiors of Uranus and Neptune, we briefly discuss their magnetic fields and atmosphere dynamics. We next introduce the challenges in constraining the formation paths of Uranus and Neptune: it is still unclear whether the planets formed at their current locations, and what the dominating processes that led to their formation (accretion rates, size of solids, etc.) were. We also mention the possible role of giant impacts shortly after their formation. Finally, we suggest that advanced modeling, future observations from space and the ground, lab experiments, and links with exoplanetary science can improve our understanding of Uranus and Neptune as a class of astronomical objects which seems to be very common in our galaxy.

G. Lacedelli, E. Pallé, Y.T. Davis, R. Luque, G. Morello, H.M. Tabernero, M.R. Zapatero Osorio, F.J. Pozuelos, D. Jankowski, G. Nowak, F. Murgas, J. Orell-Miquel, J.M. Akana-Murphy, K. Barkaoui, G. Dransfield, E. Ducrot, S. Geraldía-González, E. Jehin, H.L.M. Osborne, P. Pedersen, B.V. Rackham, M.G. Scott, M. Timmermans, A. Triaud, V. Van Eylen

The origin and evolution of the sub-Neptune population is a highly debated topic in the exoplanet community. With the advent of JWST, atmospheric studies can now put unprecedented constraints on the internal composition of this population. In this context, the THIRSTEE project aims to investigate the population properties of sub-Neptunes with a comprehensive and demographic approach, providing a homogeneous sample of precisely characterised sub-Neptunes across stellar spectral types. We present here the precise characterisation of the planetary system orbiting one of the THIRSTEE M-dwarf targets, TOI-771 (V = 14.9 mag), known to host one planet, TOI-771 b, which has been statistically validated using TESS observations. We use TESS, SPECULOOS, TRAPPIST and M-Earth photometry together with 31 high-precision ESPRESSO radial velocities to derive the orbital parameters and investigate the internal composition of TOI-771 b, as well as exploring the presence of additional companions in the system. We derive precise mass and radius for TOI-771 b, a super-Earth with R_b = 1.36 +/- 0.10 R_e and M_b = 2.47 +/- 0.32 M_e orbiting at 2.3 d. Its composition is consistent with an Earth-like planet, and it adds up to the rocky population of sub-Neptunes lying below the density gap identified around M dwarfs. With a 13% precision in mass, a 7% radius precision, and a warm equilibrium temperature of T_eq= 543 K, TOI-771 b is a particularly interesting target for atmospheric characterisation, and it is indeed one of the targets under consideration for the Rocky World DDT program. Additionally, we discover the presence of a second, non-transiting planet, TOI-771 c, with a period of 7.6 d and a minimum mass of Mp sin(i) = 2.9 +/- 0.4 M_e. Even though the inclination is not directly constrained, the planet likely belongs to the temperate sub-Neptune population, with an equilibrium temperature of 365 K.

Primordial black holes are a unique probe of the early Universe and offer a potential link between inflationary dynamics and dark matter. In a recent work \cite{Inui:2024fgk}, we analyse PBH formation and the associated stochastic gravitational wave background from scalar induced gravitational waves, while taking into account the contributions from local non-Gaussianities. We highlight the observable consequences for the LISA and PTA experiments.

Henrique Rubira, Francesco Conteddu

The multi-tracer (MT) technique has been shown to outperform single-tracer analyses in the context of galaxy clustering. In this paper, we conduct a series of Fisher analyses to further explore MT information gains within the framework of non-linear bias expansion. We examine how MT performance depends on the bias parameters of the subtracers, showing that directly splitting the non-linear bias generally leads to smaller error bars in $A_s$, $h$, and $\omega_{\rm cdm}$ compared to a simple split in $b_1$. This finding opens the door to identifying subsample splits that do not necessarily rely on very distinct linear biases. We discuss different total and subtracer number density scenarios, as well as the possibility of splitting into more than two tracers. Additionally, we consider how different Fingers-of-God suppression scales for the subsamples can be translated into different $k_{\rm max}$ values. Finally, we present forecasts for ongoing and future galaxy surveys.

C. Codella, E. Bianchi, L. Podio, M. De Simone, A. Lopez-Sepulcre, C. Ceccarelli, P. Caselli

As part of the IRAM NOEMA Large Program SOLIS, we imaged the protostellar sources SVS13-A and SVS13-B in SiO, SO, CS, and CH3OH at a spatial resolution of 2"-3" (600-900 au). The CS and SO emission traces the 5000 au envelope that hosts the SVS13-A and VLA3 young stellar objects, and CH3OH probes the compact hot corino associated with SVS13-A. In addition, CS blue-shifted emission reveals a molecular shell in the direction of the jet driven by SVS13-A that is revealed by high-velocity SiO, SO and low-velocity H_2 emission. We also imaged the protostellar jet driven by SVS13-B in SiO, and in SO, CS, and CH3OH for the first time as well. The molecules peak at different distances from the driving source: SiO(2-1) peaks at about 1600 au, and SO(2_3-1_2), CS(2--1) and CH3OH(2_k,k-1_k,k) peak at about 2000-2850 au. Moreover, SiO(2-1) emits at larger distances than SiO(5--4), indicating a lower excitation at a larger distance from the protostar. The multi-species observations revealed a stratified chemical structure in the jet of SVS13-B. A jet-like component with a transversal size < 450 au is traced by SiO, which is efficiently formed in high-velocity shocks (> 25 km/s) by sputtering and vaporisation of the grain cores and mantles. A slower and wider (transversal size of about 750 au) component is probed by methanol, which is released from dust mantles at lower shock velocities (< 10 km/s). The SO and CS emission traces an intermediate component with respect to the components probed by SiO and CH3OH. High spatial resolution imaging (down to 10 au) of the jet of SVS13-B in multiple species will aid in reconstructing the chemistry of shocked material in protostellar jets.

Marion Guelfand, Valentin Decoene, Olivier Martineau-Huynh, Simon Prunet, Matías Tueros, Oscar Macias, Aurélien Benoit-Lévy

Radio detection is now an established technique for the study of ultra-high-energy (UHE) cosmic rays with energies above $\sim10^{17}$ eV. The next-generation of radio experiments aims to extend this technique to the observation of UHE earth-skimming neutrinos, which requires the detection of very inclined extensive air showers (EAS). In this article we present a new reconstruction method for the arrival direction and the energy of EAS. It combines a point-source-like description of the radio wavefront with a phenomenological model: the Angular Distribution Function (ADF). The ADF describes the angular distribution of the radio signal amplitude in the 50-200 MHz frequency range, with a particular focus on the Cherenkov angle, a crucial feature of the radio amplitude pattern. The method is applicable to showers with zenith angles larger than $60^\circ$, and in principle up to neutrino-induced showers with up-going trajectories. It is tested here on a simulated data set of EAS induced by cosmic rays. A resolution better than 4 arc-minutes ($0.07^\circ$) is achieved on arrival direction, as well as an intrinsic resolution of 5% on the electromagnetic energy, and around 15% on the primary energy.

R. J. Jackson (1), R. D. Jeffries (1), E. Tognelli (2) ((1) Keele University UK, (2) University of New Haven USA)

Lithium is predicted, and observed, to be depleted in contracting, low-mass pre main sequence (PMS) stars. Yet these stars reach the zero age main sequence (ZAMS) with a spread in lithium abundance at a given effective temperature that is not predicted by standard stellar evolutionary models and which appears to be correlated with rotation. Using a homogeneous dataset provided by the Gaia-ESO spectroscopic survey, we have followed the evolving photospheric lithium content of cohorts of stars destined to be ZAMS late G-, K- and M-dwarfs, in clusters at ages of 2-300 Myr. We show that a dispersion in the LiI 6708A line strength develops in the lower mass stars after 10-20 Myr on the PMS, as soon as Li depletion begins, even in fully convective stars. A model based on a surface starspot coverage varying from star-to-star, leading to a differential Li-burning rate, can explain this temporal behaviour and its mass dependence. However, to fully explain the magnitude of the Li dispersion and its correlation with rotation, the spot coverage during Li-burning would need to be a factor of two larger on average than measured in ZAMS clusters like the Pleiades and continue increasing with rotation in PMS stars beyond the usual "saturation limit" observed for other magnetic activity indicators.

Symbolic Regression (SR) is a machine learning approach that explores the space of mathematical expressions to identify those that best fit a given dataset, balancing both accuracy and simplicity. We apply SR to the study of Gray-Body Factors (GBFs), which play a crucial role in the derivation of Hawking radiation and are recognized for their computational complexity. We explore simple analytical forms for the GBFs of the Schwarzschild Black Hole (BH). We compare the results obtained with different approaches and quantify their consistency with those obtained by solving the Teukolsky equation. As a case study, we apply our pipeline, which we call \texttt{ReGrayssion}, to the study of Primordial Black Holes (PBHs) as Dark Matter (DM) candidates, deriving constraints on the abundance from observations of diffuse extragalactic $\gamma$-ray background. These results highlight the possible role of SR in providing human-interpretable, approximate analytical GBF expressions, offering a new pathway for investigating PBH as a DM candidate.

E. A. Shkodkina, S. S. Savchenko, D. A. Morozova, S. G. Jorstad, G. A. Borman, T. S. Grishina, E. N. Kopatskaya, E. G. Larionova, A. A. Vasilyev, I. S. Troitskiy, Yu. V. Troitskaya, P. A. Novikova, E. V. Shishkina, A. V. Zhovtan

We present an analysis of the cross-correlation between optical brightness and polarization degree in different types of blazars. The aim is to identify objects with simultaneous and consistent changes in characteristics and to determine if this behavior relates to the types of objects studied. The analysis includes 23 objects: 11 FSRQ, 11 BL Lac, and 1 radio galaxy. Dense overlapping observation series in the R band were used, collected over more than 10 years as part of a monitoring program for bright blazars at St. Petersburg State University. The cross-correlation analysis procedure is detailed, including a method for assessing significance based on Monte Carlo simulations of synthetic light curves modeled using a Damped Random Walk. Significant correlations were found for 5 FSRQ and 1 BL Lac. No significant correlation was detected for 10 BL Lac and 6 FSRQ. One object did not yield a reliable estimate. Based on the current results, we cannot claim that the observed difference in the behavior of these emission characteristics for different classes of blazars is significant. It is possible that observed correlations may be explained by the contribution of simultaneous flare events to the changes in flux and polarization degree curves, which occur more frequently in FSRQ objects.

The origin of observed planetary systems, including our solar system, as well as their diversity is still an open question. Streaming instability (SI) is an important mechanism for the formation of gravitationally bound planetesimals, which can grow to form planetary embryos and eventually planets. Snow lines in a protoplanetary disk can assist this process, as they can form pressure maxima and promote both dust accumulation and growth. Since the sublimation of a volatile is gradual due to opacity changes, a snow line in a protoplanetary disk is in fact a radially extended "snow region" of constant temperature. Regály et al. (2021) showed that the dust can affect the disk viscosity by adsorption of charged particles and a small perturbation in gas can lead to excitation of multiple small-scale Rossby vortices. Here we investigate the possibility of excitation of Rossby vortices and rapid planetesimal formation at temperature substructures associated with the snow regions, with the help of global, two dimensional, gas-dust coupled hydrodynamic simulations, which include dust feedback and self-gravity. We find that an initial temperature substructure in a protoplanetary disk can seed a rapid cascade of long-lived, self-sustaining Rossby vortices. The vortices accumulate significant amount of dust and the local conditions are favorable for streaming instability as well as gravitational collapse. However, the vortex formation via this mechanism requires sufficient decoupling between dust and gas, and such conditions may not be satisfied at early time when the disk is dense in gas, resulting in a delayed onset of vortex formation. The self-sustaining Rossby vortices offer exceptionally favorable conditions for dust growth and formation of planetesimals, as well as a possible pathway for rapid formation of planetary cores.

Electron beams accelerated in solar flares and escaping from the Sun along open magnetic field lines can trigger intense radio emissions known as type III solar radio bursts. Utilizing observations by Parker Solar Probe (PSP), STEREO-A (STA), Solar Orbiter (SolO), and Wind spacecrafts, the speeds and accelerations of type III exciters are derived for simple and isolated type III solar bursts. For the first time, simultaneous four spacecraft observations allow to determine positions, and correct the resulting velocities and accelerations for the location between the spacecraft and the apparent source. We observe velocities and acceleration to change as $u(r) \propto r^{-0.37 \pm 0.14}$ and $a(r) \propto r^{-1.71 \pm 0.20}$ with radial distance from the Sun $r$. To explain the electron beam deceleration, we develop a simple gas-dynamic description of the electron beam moving through plasma with monotonically decreasing density. The model predicts that the beam velocity decreases as $u(f)\propto f^{1/4}(r)$, so the acceleration changes $\propto r^{-1.58}$ (and speed as $\propto r^{-0.29}$) for the plasma density profile $n(r)\propto r^{-2.3}$. The deceleration is consistent with the average observation values corrected for the type III source locations. Intriguingly, the observations also show differences in velocity and acceleration of the same type III observed by different spacecrafts. We suggest the difference could be related to the additional time delay caused by radio-wave scattering between the spacecraft and the source.

Broadly, solar wind source regions can be classified by their magnetic topology as intermittently and continuously open to the heliosphere. Early models of solar wind acceleration do not account for the fastest, non-transient solar wind speeds observed near-Earth and energy must be deposited into the solar wind after it leaves the Sun. Alfvén wave energy deposition and thermal pressure gradients are likely candidates and the relative contribution of each acceleration mechanism likely depends on the source region. Although solar wind speed is a rough proxy for solar wind source region, it cannot unambiguously identify source region topology. Using near-Sun observations of the solar wind's kinetic energy flux, we predict the expected kinetic energy flux near-Earth. This predicted kinetic energy flux corresponds to the range of solar wind speeds observed in the fast solar wind and infer that the solar wind's near-Sun kinetic energy flux is sufficient to predict the distribution of fastest, non-transient speeds observed near Earth. Applying a recently developed model of solar wind evolution in the inner heliosphere, we suggest that the acceleration required to generate this distribution of fastest, non-transient speeds is likely due to the continuous deposition of energy by Alfvén wave forcing during the solar wind's propagation through interplanetary space. We infer that the solar wind's Alfvénicity can statistically map near-Earth observations to their source regions because the Alfvén wave forcing that the solar wind experiences in transit is a consequence of the source region topology.

While mounting observational evidence suggests that intermediate mass black holes (IMBHs) may be important in shaping the properties of dwarf galaxies both at high redshifts and in the local Universe, our theoretical understanding of how these IMBHs grow is largely incomplete. To address this, we perform high-resolution simulations of an isolated dwarf galaxy with a virial mass of $10^{10}~{\rm M}_{\odot}$ harbouring a $10^4~{\rm M}_{\odot}$ IMBH at its centre at a peak spatial resolution of $\lesssim 0.01$ pc. Within the fully multi-phase interstellar medium (ISM), we incorporate explicit sampling of stars from the initial mass function, photo-ionization, photoelectric heating, individual supernovae (SNe), as well as a Shakura-Sunyaev accretion disc model to track the evolution of BH mass and spin. We find that a nuclear star cluster (NSC) effectively captures the ISM gas and promotes formation of a circumnuclear disc (CND) on scales of $\lesssim 7$ pc. Simultaneously, gravitational torques from the NSC reduce CND angular momentum on (sub-)parsec scales, circularizing the gas onto the $\alpha$-accretion disc and promoting sustained IMBH growth at $\sim 0.01$ of the Eddington rate. While in the innermost regions ($\lesssim 0.5$ pc), star formation is highly suppressed, the CND is susceptible to fragmentation, leading to the formation of massive, young stars. Interestingly, despite an in-situ SN rate of $0.3~{\rm Myr}^{-1}$, the dense CND persists, sustaining BH accretion and leading to its net spin-up. Our study demonstrates the complexity of IMBH accretion within a multi-phase ISM, and paves the way for next-generation studies where IMBH growth in a fully cosmological context can be captured.

We present a systematic comparison of statistical approaches to Baryon Acoustic Oscillation (BAO) analysis using DESI DR2 data. We evaluate four methods for handling the nuisance parameter $\beta=1/(H_0 r_d)$: marginalization, profiling, Taylor expansion, and full likelihood analysis across multiple cosmological models. Our results demonstrate that while these methods yield consistent constraints for $\Lambda$CDM and $\Omega_K$CDM models, they produce notable differences for models with dynamical dark energy parameters. Through eigenvalue decomposition of Fisher matrices, we identify extreme parameter degeneracies in $ww_a$CDM and $\Omega_Kww_a$CDM models that explain these statistical sensitivities. Surprisingly, $\Omega_K$CDM shows the highest information content across datasets, suggesting BAO measurements are particularly informative about spatial curvature. We further use skewness and kurtosis analysis to identify deviations from Gaussianity, highlighting limitations in Fisher approximations in the dark energy models. Our analysis demonstrates the importance of careful statistical treatment when extracting cosmological constraints from increasingly precise measurements.

We use a probability theory framework to discuss the search for biosignatures. This perspective allows us to analyse the potential for different biosignatures to provide convincing evidence of extraterrestrial life and to formalise frameworks for accumulating evidence. Analysing biosignatures as a function of planetary context motivates the introduction of 'peribiosignatures', biosignatures observed where life is unlikely. We argue, based on prior work in Gaia theory, that habitability itself is an example of a peribiosignature. Finally, we discuss the implications of context dependence on observational strategy, suggesting that searching the edges of the habitable zone rather than the middle might be more likely to provide convincing evidence of life.

This work aims to develop a method based on a structurally reliable ice model and a statistically and physico-chemically robust approach for BE distribution inference, with the aim to be applicable to various relevant interstellar species. A multiscale computational approach is presented, with a Molecular Dynamics (MD) Heat & Quench protocol for the amorphous water ice model, and an ONIOM(B3LYP-D3(BJ)/6-311+G**:GFN2-xtb) scheme for the BE inference, with a prime emphasis onto the BE/real system size convergence. The sampling of the binding configurations is twofold, exploring both regularly spaced binding sites, as well as various adsorbate-to-substrate orientations on each locally distinct site. This second source of BE diversity accounts for the local roughness of the potential energy landscape of the substrate. Three different adsorbate test cases are considered, i.e. NH3, CO and CH4, owing to their significance in dust icy mantles, and their distinct binding behavior with water ices. The BE distributions for NH3, CO and CH4 have been inferred, with converged statistics. The distribution for NH3 is better represented by a double Gaussian component profile. Three starting adsorbate orientations per site are required to reach convergence for both Gaussian components of NH3, while 2 orientations are sufficient for CO, and one unique for CH4 (symmetric). Further geometrical and molecular surrounding insights have been provided. These results encompass previously reported results.

The emerging generation of radio-interferometric (RI) arrays are set to form images of the sky with a new regime of sensitivity and resolution. This implies a significant increase in visibility data volumes, scaling as $\mathcal{O}(Q^{2}B)$ for $Q$ antennas and $B$ short-time integration intervals (or batches), calling for efficient data dimensionality reduction techniques. This paper proposes a new approach to data compression during acquisition, coined modulated rank-one projection (MROP). MROP compresses the $Q\times Q$ batchwise covariance matrix into a smaller number $P$ of random rank-one projections and compresses across time by trading $B$ for a smaller number $M$ of random modulations of the ROP measurement vectors. Firstly, we introduce a dual perspective on the MROP acquisition, which can either be understood as random beamforming, or as a post-correlation compression. Secondly, we analyse the noise statistics of MROPs and demonstrate that the random projections induce a uniform noise level across measurements independently of the visibility-weighting scheme used. Thirdly, we propose a detailed analysis of the memory and computational cost requirements across the data acquisition and image reconstruction stages, with comparison to state-of-the-art dimensionality reduction approaches. Finally, the MROP model is validated in simulation for monochromatic intensity imaging, with comparison to the classical and baseline-dependent averaging (BDA) models, and using the uSARA optimisation algorithm for image formation. An extensive experimental setup is considered, with ground-truth images containing diffuse and faint emission and spanning a wide variety of dynamic ranges, and for a range of $uv$-coverages corresponding to VLA and MeerKAT observation.

C. Garcia-Quintero, H. E. Noriega, A. de Mattia, A. Aviles, K. Lodha, D. Chebat, J. Rohlf, S. Nadathur, W. Elbers, J. Aguilar, S. Ahlen, O. Alves, U. Andrade, S. BenZvi, D. Bianchi, D. Brooks, R. Calderon, A. Carnero Rosell, P. Carrilho, E. Chaussidon, T. Claybaugh, A. Cuceu, R. de Belsunce, A. de la Macorra, N. Deiosso, J. Della Costa, Biprateep Dey, Z. Ding, P. Doel, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, H. Gil-Marín, S. Gontcho A Gontcho, G. Gutierrez, J. Guy, K. Honscheid, C. Howlett, D. Huterer, M. Ishak, S. Juneau, D. Kirkby, A. Kremin, O. Lahav, C. Lamman, M. Landriau, L. Le Guillou, M. E. Levi, Q. Li, M. Manera, W. L. Matthewson, A. Meisner, J. Mena-Fernández, R. Miquel, J. Moustakas, J. A. Newman, G. Niz, E. Paillas, N. Palanque-Delabrouille, J. Pan, W. J. Percival, F. Prada, I. Pérez-Ràfols, M. Rashkovetskyi, C. Ravoux, A. J. Ross, G. Rossi, E. Sanchez, D. Schlegel, M. Schubnell, A. Shafieloo, D. Sprayberry, G. Tarlé, P. Taylor, M. Vargas-Magaña, B. A. Weaver, C. Yèche, P. Zarrouk, Z. Zhai, R. Zhou

We report cosmological results from the Dark Energy Spectroscopic Instrument (DESI) measurements of baryon acoustic oscillations (BAO) when combined with recent data from the Atacama Cosmology Telescope (ACT). By jointly analyzing ACT and {\it Planck} data and applying conservative cuts to overlapping multipole ranges, we assess how different {\it Planck}+ACT dataset combinations affect consistency with DESI. While ACT alone exhibits a tension with DESI exceeding 3$\sigma$ within the $\Lambda$CDM model, this discrepancy is reduced when ACT is analyzed in combination with {\it Planck}. For our baseline DESI DR2 BAO+{\it Planck} PR4+ACT likelihood combination, the preference for evolving dark energy over a cosmological constant is about 3$\sigma$, increasing to over 4$\sigma$ with the inclusion of Type Ia supernova data. While the dark energy results remain quite consistent across various combinations of {\it Planck} and ACT likelihoods with those obtained by the DESI collaboration, the constraints on neutrino mass are more sensitive, ranging from $\sum m_\nu < 0.061$ eV in our baseline analysis, to $\sum m_\nu < 0.077$ eV (95\% confidence level) in the CMB likelihood combination chosen by ACT when imposing the physical prior $\sum m_\nu>0$ eV.

A key signature of general relativity is that the two scalar potentials $\Phi$ and $\Psi$, when expressed in the longitudinal gauge, are equal in the absence of fluids with anisotropic stress. This is often expressed by stating that their ratio, the "gravitational slip", is equal to unity. However, the equality of $\Phi$ and $\Psi$ is typically broken in alternative theories of gravity. Observational constraints on the slip parameter are therefore of direct interest for testing Einstein's theory. In this paper we derive theory-independent expressions for the slip parameter on both large and small scales in Friedmann cosmologies, expressing it as a function of the post-Newtonian parameters. This is the final ingredient required for a complete parameterization of dust and dark energy-dominated cosmologies within the framework of Parameterized Post-Newtonian Cosmology (PPNC), which allows for the fully self-consistent modelling of cosmological observables without assuming any specific theory of gravity.

Tobias M. Schmidt, Ansgar Reiners, Michael T. Murphy, Gaspare Lo Curto, Carlos J. A. P. Martins, Philipp Huke

High quality wavelength calibration is crucial for science cases like radial-velocity studies of exoplanets, the search for a possible variation of fundamental constants, and the redshift drift experiment. However, for state-of-the-art spectrographs it has become difficult to verify the wavelength calibration on sky, because no astrophysical source provides spectra with sufficiently stable or accurate wavelength information. We therefore propose to use iodine absorption cells to validate the wavelength calibration. Observing a bright and featureless star through the iodine cell emulates an astrophysical target with exactly known spectral features that can be analyzed like any other science target, allowing to verify the wavelength calibration derived from the internal calibration sources and to identify systematics in the data processing. As demonstration, we temporarily installed an I$_2$ absorption cell at ESPRESSO. Employing a full forward modeling approach of the I$_2$ spectrum, including the instrumental line-spread function, we demonstrate wavelength calibration accuracy at the level of a few m/s. We also show that wavelength measurements do depend on the geometry of the light-injection into the spectrograph fibers. This highlights the importance of probing exactly the same light path as science targets, something not possible with internal calibration sources alone. We also demonstrate excellent radial-velocity stability at the <20 cm/s level in a full end-to-end fashion, from sky to data product. Our study therefore showcases the great potential of absorption cells for the verification and long-term monitoring of the wavelength calibration as well as the unique insights they can provide.

F. Quispe-Huaynasi, F. Roig, N. Holanda, V. Loaiza-Tacuri, Romualdo Eleutério, C. B. Pereira, S. Daflon, V. M. Placco, R. Lopes de Oliveira, F. Sestito, P. K. Humire, M. Borges Fernandes, A. Kanaan, T. Ribeiro, W. Schoenell

Identification of specific stellar populations using photometry for spectroscopic follow-up is a first step to confirm and better understand their nature. In this context, we present an unsupervised machine learning approach to identify candidates for spectroscopic follow-up using data from the Southern Photometric Local Universe Survey (S-PLUS). First, using an anomaly detection technique based on an autoencoder model, we select a large sample of objects ($\sim 19,000$) whose Spectral Energy Distribution (SED) is not well reconstructed by the model after training it on a well-behaved star sample. Then, we apply the t-distributed Stochastic Neighbor Embedding (t-SNE) algorithm to the 66 color measurements from S-PLUS, complemented by information from the SIMBAD database, to identify stellar populations. Our analysis reveals 69 carbon-rich star candidates that, based on their spatial and kinematic characteristics, may belong to the CH or Carbon-Enhanced Metal-Poor (CEMP) categories. Among these chemically peculiar candidates, we identify four as likely carbon dwarf stars. We show that it is feasible to identify three primary white dwarf (WD) populations: WDs with hydrogen-dominated atmospheres (DA), WDs with neutral helium-dominated atmospheres (DB), and the WDs main sequence binaries (WD + MS). Furthermore, by using eROSITA X-ray data, we also highlight the identification of candidates for very active low-mass stars. Finally, we identified a large number of binary systems using the autoencoder model, but did not observe a clear association between the overdensities in the t-SNE map and their orbital properties.

Janvi P. Madhani, Charlotte Welker, Sneha Nair, Daniel Gallego, Lianys Feliciano, Christophe Pichon, Charlotte Olsen, Yohan Dubois, Sugata Kaviraj, Katarina Kraljic

We investigate dwarf satellite systems around Milky Way analogs in the NewHorizon simulation. Using simple estimators limiting over-detection, we identify planes of satellites comparable to observations in $30\%$ to $70\%$ of cases. The full sample is strongly biased towards arrangements more elongated and co-rotating than their dark-matter host, as early as $z = 1$. We identify cosmic filaments and relics of local gas streams outside each system at $z \approx 0$ with DisPerSE. We find that the thinner the local stream plane, the thinner the system is. The two align significantly for planar systems. Streams around isotropic systems are not planar. Our analysis reveals two plane types. Ultrathin planes lie orthogonally to their single nearest cosmic filament and align to coherent vortical flows within 3 Mpc, reminiscent of $z > 2$ whirls. A second group of planar systems align to their cosmic filaments. All planes are found in single cosmic filaments skirted by coherent vortical whirls while isotropic systems are found in turbulent flows at the intersection of filaments. We conclude that planes are frequent in $\Lambda CDM$ simulations providing the cosmic environment is resolved. Tracking filaments back in time, we show a tight connection between a single, stable filament down to $z \approx 0$ and the existence of a plane. "In-filament" planes typically get enhanced by a single, edge-on filament merger at $z < 2$ (zipper) while "vertical" planes' filaments undergo single twisters (high-orbital momentum zippers) preventing the formation of a core along the filament. In contrast, isotropic systems' filaments undergo multiple misaligned mergers.

Maya Horton, Martin Hardcastle, George Miley, Cyril Tasse, Timothy Shimwell

The LOw Frequency ARray Two-metre Sky Survey second data release (LoTSS DR2) covers 27\% of the northern sky and contains around four million radio sources. The development of this catalogue involved a large citizen science project (Radio Galaxy Zoo: LOFAR) with more than 116,000 resolved sources going through visual inspection. We took a subset of sources with flux density above 75 mJy and an angular size of $90''$ or greater, giving a total of $9,985$ sources or $\sim 10\%$ of the visually inspected sources. We classified these by visual inspection in terms of broad source type (e.g., Fanaroff-Riley class I or II, narrow or wide-angle tail, relaxed double), noticeable features (wings, visible jets, banding, filaments etc), environmental features (cluster environment, merger, diffuse emission). Our specific aim was to search for features linked to jet precession, such as a misaligned jet axis, curvature and multiple hotspots. This combination of features and morphology allowed us to detect increasingly fine-grained sub-populations of interesting or unusual sources. We found that $28\%$ of sources showed evidence of one or more precession indicators, which could make them candidates for hosting close binary supermassive black holes. Potential precession signatures occur in sources of all sizes and luminosities in our sample but appear to favour more massive host galaxies. Our work greatly expands the sample size and parameter space of searches for precession signatures in powerful jetted sources. This work also showcases the diversity of large bright radio sources in the LOFAR surveys, whether or not precession indicators are present.

Chemical tagging is a central pursuit of galactic archaeology, but requires sufficiently discriminative abundances to uniquely identify sites of star formation. This task is complicated by intrinsic scatter among conatal stars, inter-element correlations, imprecise abundance measurements, and systematics across stellar evolutionary states. In this work, we formalize the abundance correlation structure of the disk by quantifying the amplitude of information in individual element abundances once a subset is known, and map inter-element residual correlations to uncover hidden signatures of nucleosynthesis. We use two datasets of 79 (593) stars across $-0.15<\rm [Fe/H]<0.13$ ($-1<\rm [Fe/H]<0.41$) with measurements of 30 (19) element abundances of solar neighborhood stars, including 11 (7) light and $\alpha$, 7 (3) Fe-peak, and 12 (9) neutron capture elements. With a simple linear regression model, we predict most $\alpha$ and Fe-peak element abundances within 0.03~dex ($\sim7\%$), and neutron capture elements within 0.05~dex ($\sim10\%$). Including first and second peak s-process elements as predictors improves most neutron capture element predictions to within 0.02~dex (5\%), although no predictive power is gained by including an r-process element. We uncover strong (anti-)correlations in small residual abundances between and within element families. Our finding that disk abundance space is rigidly coupled, from light to heavy elements, implies chemical tagging is infeasible at $>2\%$ precision for $\sim$30 elements. However, the residual structure encodes fingerprints of star formation history, inherited from nucleosynthesis and environmental variations, and provides critical constraints for chemical evolution models. Future disk surveys must achieve sub-2-5\% precision in 30+ elements to access this independent information.

E. Ceccotti, A. R. Offringa, F. G. Mertens, L. V. E. Koopmans, S. Munshi, J. K. Chege, A. Acharya, S. A. Brackenhoff, E. Chapman, B. Ciardi, R. Ghara, S. Ghosh, S. K. Giri, C. Höfer, I. Hothi, G. Mellema, M. Mevius, V. N. Pandey, S. Zaroubi

The redshifted 21-cm signal of neutral hydrogen from the Epoch of Reionization (EoR) can potentially be detected using low-frequency radio instruments such as the Low-Frequency Array (LOFAR). So far, LOFAR upper limits on the 21-cm signal power spectrum have been published using a single target field: the North Celestial Pole (NCP). In this work, we analyse and provide upper limits for the 3C196 field, observed by LOFAR, with a strong ${\approx}80\,$Jy source in the centre. This field offers advantages such as higher sensitivity due to zenith-crossing observations and reduced geostationary radio-frequency interference, but also poses challenges due to the presence of the bright central source. After constructing a wide-field sky model, we process a single 6-hour night of 3C196 observations using direction-independent and direction-dependent calibration, followed by a residual foreground subtraction with a machine learned Gaussian process regression (ML-GPR). A bias correction is necessary to account for signal suppression in the GPR step. Still, even after this correction, the upper limits are a factor of two lower than previous single-night NCP results, with a lowest $2\sigma$ upper limit of $(146.61\,\text{mK})^2$ at $z = 9.16$ and $k=0.078\,h\,\text{cMpc}^{-1}$ (with $\text{d}k/k\approx 0.3$). The results also reveal an excess power, different in behaviour from that observed in the NCP field, suggesting a potential residual foreground origin. In future work, the use of multiple nights of 3C196 observations combined with improvements to sky modelling and ML-GPR to avoid the need for bias correction should provide tighter constraints per unit observing time than the NCP.

A precise determination of the bubble wall velocity $v_w$ is crucial for making accurate predictions of the baryon asymmetry and gravitational wave (GW) signals in models of electroweak baryogenesis (EWBG). Working in the local thermal equilibrium approximation, we exploit entropy conservation to present efficient algorithms for computing $v_w$, significantly streamlining the calculation. We then explore the parameter dependencies of $v_w$, focusing on two sample models capable of enabling a strong first-order electroweak phase transition: a $\mathbb{Z}_2$-symmetric singlet extension of the SM, and a model for baryogenesis with CP violation in the dark sector. We study correlations among $v_w$ and the two common measures of phase transition strength, $\alpha_n$ and $v_n/T_n$. Interestingly, we find a relatively model-insensitive relationship between $v_n/T_n$ and $\alpha_n$. We also observe an upper bound on $\alpha_n$ for the deflagration/hybrid wall profiles naturally compatible with EWBG, the exact value for which varies between models, significantly impacting the strength of the GW signals. In summary, our work provides a framework for exploring the feasibility of EWBG models in light of future GW signals.

We apply the criterion of finite naturalness to the limiting case of a generic heavy sector decoupled from the Standard Model. The sole and unavoidable exception to this decoupling arises from gravitational interactions. We demonstrate that gravity can couple the Higgs to the heavy scale significantly earlier than the well-known three-loop top-quark-mediated diagrams discussed in previous literature. As an application, we show that finite naturalness disfavors large-field inflationary models involving super-Planckian field excursions. In contrast, in the small-field regime, achieving successful inflation requires substantial fine-tuning of the initial conditions, in agreement with previous results. Recent data from the Atacama Cosmology Telescope further amplify the tension between naturalness and fine-tuning, challenging the theoretical robustness of single-field inflation as a compelling explanation for the origin of the universe.

Enrico Specogna, Shahnawaz A. Adil, Emre Ozulker, Eleonora Di Valentino, Rafael C. Nunes, Ozgur Akarsu, Anjan A. Sen

In this work, we present updated observational constraints on the parameter space of the DMS20 dark energy model, a member of the omnipotent dark energy (ODE) class. Our analysis combines multiple CMB datasets - including measurements from the Planck satellite (PL18), the South Pole Telescope (SPT), and the Wilkinson Microwave Anisotropy Probe (WMAP) - with Type Ia supernova data from the Pantheon+ catalog (PP), and baryon acoustic oscillation (BAO) measurements from the DESI and SDSS surveys. We find that certain data combinations, such as SPT+WMAP+BAO and PL18+BAO, can reduce the significance of the $H_0$ tension below $1\sigma$, but with considerably large uncertainties. These same combinations also predict suppressed structure growth, favoring lower values of $S_8$ compared to the Planck-only constraint. However, the inclusion of PP data restores the tension in $H_0$. To provide a comprehensive view of the ODE phenomenology, we also investigate the evolution of its energy density, emphasizing its dynamical behavior at low redshifts. Our results generically exhibit multiple phantom divide line (PDL) crossings in a single expansion history, a behavior that is not compatible with single scalar field scenarios.

Steven van der Vlugt, Leon Oostrum, Gijs Schoonderbeek, Ben van Werkhoven, Bram Veenboer, Krijn Doekemeijer, John W. Romein

Power consumption is a major concern in data centers and HPC applications, with GPUs typically accounting for more than half of system power usage. While accurate power measurement tools are crucial for optimizing the energy efficiency of (GPU) applications, both built-in power sensors as well as state-of-the-art power meters often lack the accuracy and temporal granularity needed, or are impractical to use. Released as open hardware, firmware, and software, PowerSensor3 provides a cost-effective solution for evaluating energy efficiency, enabling advancements in sustainable computing. The toolkit consists of a baseboard with a variety of sensor modules accompanied by host libraries with C++ and Python bindings. PowerSensor3 enables real-time power measurements of SoC boards and PCIe cards, including GPUs, FPGAs, NICs, SSDs, and domain-specific AI and ML accelerators. Additionally, it provides significant improvements over previous tools, such as a robust and modular design, current sensors resistant to external interference, simplified calibration, and a sampling rate up to 20 kHz, which is essential to identify GPU behavior at high temporal granularity. This work describes the toolkit design, evaluates its performance characteristics, and shows several use cases (GPUs, NVIDIA Jetson AGX Orin, and SSD), demonstrating PowerSensor3's potential to significantly enhance energy efficiency in modern computing environments.

We propose a quantum teleportation-based speed meter for interferometric displacement sensing. Two equivalent implementations are presented: an online approach that uses real-time displacement operation and an offline approach that relies on post-processing. Both implementations reduce quantum radiation pressure noise and surpass the standard quantum limit of measuring displacement. We discuss potential applications to gravitational-wave detectors, where our scheme enhances low-frequency sensitivity without requiring modifications to the core optics of a conventional Michelson interferometer (e.g., substrate or coating properties). This approach offers a new path to back-action evasion enabled by quantum entanglement.

We investigate the influence of the generalized Compton wavelength (GCW), emerging from a three-dimensional dynamical quantum vacuum (3D DQV) on Schwarzschild-like black hole spacetimes, motivated by the work of Fiscaletti [https://doi.org/10.1134/S0040577925020096] \cite{Fiscaletti:2025iuh}. The GCW modifies the classical geometry through a deformation parameter $ \varepsilon $, encoding quantum gravitational backreaction. We derive exact analytical expressions for the black hole shadow radius, photon sphere, and weak deflection angle, incorporating higher-order corrections and finite-distance effects of a black hole with generalized Compton effect (BHGCE). Using Event Horizon Telescope (EHT) data, constraints on $ \varepsilon $ are obtained: $ \varepsilon \in [-2.572, 0.336] $ for Sgr. A* and $ \varepsilon \in [-2.070, 0.620] $ for M87*, both consistent with general relativity yet allowing moderate deviations. Weak lensing analyses via the Keeton-Petters and Gauss-Bonnet formalisms further constrain $ \varepsilon \approx 0.061 $, aligning with solar system bounds. We compute the modified Hawking temperature, showing that positive $ \varepsilon $ suppresses black hole evaporation. Quasinormal mode frequencies in the eikonal limit are also derived, demonstrating that both the oscillation frequency and damping rate shift under GCW-induced corrections. Additionally, the gravitational redshift and scalar perturbation waveform exhibit deformations sensitive to $ \varepsilon $. Our results highlight the GCW framework as a phenomenologically viable semiclassical model, offering testable predictions for upcoming gravitational wave and VLBI observations.

We present results for the equation of state of symmetric nuclear matter and pure neutron matter obtained in many-body-perturbation theory (MBPT) up to third order, based on various chiral nucleon-nucleon and three-nucleon interactions used in ab initio calculations of nuclei. We extract equation of state properties, such as the incompressibility and the symmetry energy, and discuss estimates of the theoretical uncertainties due to neglected higher-order contributions in the MBPT expansion as well as the chiral effective field theory expansion. In addition, we discuss the Fermi liquid approach to nuclear matter and present results for the Landau parameters, effective mass, and speed of sound for pure neutron matter.

G. Angloher, M. R. Bharadwaj, A. Böhmer, M. Cababie, I. Colantoni, I. Dafinei, N. Di Marco, C. Dittmar, L. Einfalt, F. Ferella, F. Ferroni, S. Fichtinger, A. Filipponi, T. Frank, M. Friedl, Z. Ge, M. Heikinheimo, M. N. Hughes, K. Huitu, M. Kellermann, R. Maji, M. Mancuso, L. Pagnanini, F. Petricca, S. Pirro, F. Pröbst, G. Profeta, A. Puiu, F. Reindl, K. Schäffner, J. Schieck, P. Schreiner, C. Schwertner, K. Shera, M. Stahlberg, A. Stendahl, M. Stukel, C. Tresca, F. Wagner, S. Yue, V. Zema, Y. Zhu, The COSINUS Collaboration

COSINUS is a dark matter direct detection experiment using NaI crystals as cryogenic scintillating calorimeters. If no signal is observed, this will constrain the dark matter scattering rate in sodium iodide. We investigate how this constraint can be used to infer that the annual modulation signal observed in DAMA/LIBRA experiment cannot originate from dark matter nuclear recoil events, independent of the DM model. We achieve this by unfolding the DAMA modulation spectrum to obtain the implied unquenched nuclear recoil spectrum, which we compare to the expected COSINUS sensitivity. We find that assuming zero background in the signal region, a 1$\sigma$, 2$\sigma$ or 3$\sigma$ confidence limit exclusion can be obtained with 57, 130 or 250 kg day of exposure, respectively.

We critically reanalyze the relativistic precession model of quasi-periodic oscillations, exploring its natural extension beyond the standard harmonic approximation. To do so, we show that the perturbed geodesic equations must include anharmonic contributions arising from the higher-order expansion of the effective potential that cannot be neglected \emph{a priori}, as commonly done in all the approaches pursued so far. More specifically, independently of the underlying spacetime geometry, we find that in the radial sector the non-negligible anharmonic correction is quadratic in the radial displacement, i.e. $\propto \delta r^2$, and significantly affects the radial epicyclic frequency close to the innermost stable circular orbit. Conversely, polar oscillations $\delta \theta$ remain approximately decoupled from radial ones, preserving their independent dynamical behavior. To show the need of anharmonic corrections, we thus carry out Monte Carlo-Markov chain analyses on eight neutron star sources of quasi-periodic oscillations. Afterwards, we first work out the outcomes of the harmonic approximation in Schwarzschild, Schwarzschild--de Sitter, and Kerr spacetimes. Subsequently, we apply the anharmonic corrections to them and use it to fit the aforementioned neutron star sources. Our findings indicate that the standard paradigm requires a systematic generalization to include the leading anharmonic corrections that appear physically necessary, although still insufficient to fully account for the observed phenomenology of quasi-periodic oscillations. Accordingly, we speculate on possible refinements of the relativistic precession model, showing the need to revise it at a fundamental level.

In cosmic inflation, non-linearities of the curvature perturbation can induce backreaction to the background. To obtain observational predictions at non-linear order on the correct background, one has to redefine the background or introduce background renormalization. We explicitly demonstrate it with a vanishing one-point function of the curvature perturbation as a renormalization condition, so that proper observational predictions can be made even at the nonlinear level. Due to non-linear symmetry of the curvature perturbation, such a procedure induces corrections to the two-point functions, which yield a finite renormalized one-loop correction that depends on the regularization scheme. Cancellation of the divergence is a manifestation of Maldacena's consistency condition. The finite term can be large and highly time-dependent, which indicates evolution outside the horizon.