Papers for Friday, Jan 20 2023

Gaps in circumstellar disks can signal the existence of planetary perturbers, making such systems preferred targets for direct imaging observations of exoplanets. Being one of the brightest and closest stars to the Sun, the photometric standard star Vega hosts a two-belt debris disk structure. Together with the fact that its planetary system is being viewed nearly face-on, Vega has been one of the prime targets for planet imaging efforts. Using the vector vortex coronagraph on Keck/NIRC2 in Ms-band at 4.67 $\mu$m, we report the planet detection limits from 1 au to 22 au for Vega with an on-target time of 1.8 h. We reach a 3 Jupiter mass limit exterior to 12 au, which is nearly an order of magnitude deeper than existing studies. Combining with existing radial velocity studies, we can confidently rule out the existence of companions more than ~8 Jupiter mass from 22 au down to 0.1 au for Vega. Interior and exterior to ~4 au, this combined approach reaches planet detection limits down to ~2-3 Jupiter mass using radial velocity and direct imaging, respectively. By reaching multi-Jupiter mass detection limits, our results are expected to be complemented by the planet imaging of Vega in the upcoming observations using the James Webb Space Telescope to obtain a more holistic understanding of the planetary system configuration around Vega.

Differential rotation is thought to be responsible for the dynamo process in stars like our Sun, driving magnetic activity and star spots. We report that star spot measurements in the Praesepe open cluster are strongly enhanced only for stars which depart from standard models of rotational evolution. A decoupling of the spin down history between the core and envelope explains both the activity and rotation anomalies: surface rotational evolution is stalled by interior angular momentum redistribution, and the resultant radial shears enhance star spot activity. These anomalies provide evidence for an evolving front of shear-enhanced activity affecting the magnetic and rotational evolution of cool stars and the high-energy environments of their planetary companions for hundreds of millions to billions of years on the main sequence.

We use a suite of 3D simulations of star-forming molecular clouds, with and without stellar feedback, magnetic fields, and driven turbulence, to study the compression and expansion rates of the gas as functions of density. We show that, around the mean density, supersonic turbulence promotes rough equilibrium between the amounts of compressing and expanding gas, consistent with continuous gas cycling between high and low density states. We find that the inclusion of protostellar jets produces rapidly expanding and compressing low-density gas. We find that the gas mass flux peaks at the transition between the lognormal and power-law forms of the density probability distribution function (PDF). This is consistent with the transition density tracking the post-shock density, which promotes an enhancement of mass at this density (i.e., shock compression and filament formation). At high densities, the gas dynamics are dominated by self-gravity: the compression rate in all of our runs matches the rate of the run with only gravity, suggesting that processes other than self-gravity have little effect at these densities. The net gas mass flux becomes constant at a density below the sink formation threshold, where it equals the star formation rate. The density at which the net gas mass flux equals the star formation rate is one order of magnitude lower than our sink threshold density, corresponds to the formation of the second power-law tail in the density PDF, and sets the overall star formation rates of these simulations.

We assemble a sample of 696 type 1 AGN up to a redshift of $z=2.5$, all of which have an SDSS spectrum containing at least one broad emission line (H $\alpha$, H $\beta$ or Mg II) and an XMM-Newton X-ray spectrum containing at least 250 counts in addition to simultaneous optical/ultraviolet photometry from the XMM Optical Monitor. Our sample includes quasars and narrow-line Seyfert 1s: thus our AGN span a wide range in luminosity, black hole mass and accretion rate. We determine single-epoch black hole mass relations for the three emission lines and find that they provide broadly consistent mass estimates whether the continuum or emission line luminosity is used as the proxy for the broad emission line region radius. We explore variations of the UV/X-ray energy index $\alpha_\mathrm{ox}$ with the UV continuum luminosity and with black hole mass and accretion rate, and make comparisons to the physical quasar spectral energy distribution (SED) model QSOSED. The majority of the AGN in our sample lie in a region of parameter space with $0.02<L/L_\mathrm{Edd}<2$ as defined by this model, with narrow-line type 1 AGN offset to lower masses and higher accretion rates than typical broad-line quasars. We find differences in the dependence of $\alpha_\mathrm{ox}$ on UV luminosity between both narrow/broad-line and radio-loud/quiet subsets of AGN: $\alpha_\mathrm{ox}$ has a slightly weaker dependence on UV luminosity for broad-line AGN and radio-loud AGN have systematically harder $\alpha_\mathrm{ox}$.

We have undertaken a Near-IR Weak Lensing (NIRWL) analysis of the wide-field CANDELS HST/WFC3-IR F160W observations. With the Gaia proper-motion-corrected catalog as an astrometric reference, we updated the astrometry of the five CANDELS mosaics and achieved an absolute alignment within $0.02\pm0.02$ arcsec on average, which is a factor of several superior to existing mosaics. These mosaics are available to download. We investigated the systematic effects that need to be corrected for weak-lensing measurements. We find the largest contributing systematic effect is caused by undersampling. Using stars as a probe of the point-spread function (PSF), we find a sub-pixel centroid dependence on the PSF shape that induces a change in the PSF ellipticity and size by up to 0.02 and $3\%$, respectively. We find that the brighter-fatter effect causes a $2\%$ increase in the size of the PSF and discover a brighter-rounder effect that changes the ellipticity by 0.006. Based on the narrow bandpasses of the WFC3-IR filters and the small range of slopes in a galaxy's spectral energy distribution (SED) within the bandpasses, we suggest that the impact of galaxy SED on PSF is minor in the NIR. Finally, we modeled the PSF of WFC3-IR F160W for weak lensing using a principal component analysis. The PSF models account for temporal and spatial variations of the PSF. The PSF corrections result in residual ellipticities and sizes, $|de_1| < 0.0005\pm0.0003$, $|de_2| < 0.0005\pm0.0003$, and $|dR| < 0.0005\pm0.0001$, that are sufficient for the upcoming NIRWL search for massive overdensities in the five CANDELS fields. NIRWL Mosaics: https://drive.google.com/drive/folders/1k9WEV3tBOuRKBlcaTJ0-wTZnUCisS__r?usp=share_link

The distribution of close-in exoplanets is shaped by a complex interplay between atmospheric and dynamical processes. The Desert-Rim Exoplanets Atmosphere and Migration (DREAM) program aims at disentangling those processes through the study of the hot Neptune desert, whose rim hosts planets that are undergoing, or survived, atmospheric evaporation and orbital migration. In this first paper, we use the Rossiter-McLaughlin Revolutions (RMR) technique to investigate the orbital architecture of 14 close-in planets ranging from mini-Neptune to Jupiter-size and covering a broad range of orbital distances. While no signal is detected for the two smallest planets, we were able to constrain the sky-projected spin--orbit angle of six planets for the first time, to revise its value for six others, and, thanks to constraints on the stellar inclination, to derive the 3D orbital architecture in seven systems. These results reveal a striking three-quarters of polar orbits in our sample, all being systems with a single close-in planet but of various stellar and planetary types. High-eccentricity migration is favored to explain such orbits for several evaporating warm Neptunes, supporting the role of late migration in shaping the desert and populating its rim. Putting our measurements in the wider context of the close-in planet population will be useful to investigate the various processes shaping their architectures.

Strong gravitational lensing and microlensing of supernovae (SNe) are emerging as a new probe of cosmology and astrophysics in recent years. We provide an overview of this nascent research field, starting with a summary of the first discoveries of strongly lensed SNe. We describe the use of the time delays between multiple SN images as a way to measure cosmological distances and thus constrain cosmological parameters, particularly the Hubble constant, whose value is currently under heated debates. New methods for measuring the time delays in lensed SNe have been developed, and the sample of lensed SNe from the upcoming Rubin Observatory Legacy Survey of Space and Time (LSST) is expected to provide competitive cosmological constraints. Lensed SNe are also powerful astrophysical probes. We review the usage of lensed SNe to constrain SN progenitors, acquire high-z SN spectra through lensing magnifications, infer SN sizes via microlensing, and measure properties of dust in galaxies. The current challenge in the field is the rarity and difficulty in finding lensed SNe. We describe various methods and ongoing efforts to find these spectacular explosions, forecast the properties of the expected sample of lensed SNe from upcoming surveys particularly the LSST, and summarize the observational follow-up requirements to enable the various scientific studies. We anticipate the upcoming years to be exciting with a boom in lensed SN discoveries.

Context.Measurements of the occultation of an exoplanet at visible wavelengths allow us to determine the reflective properties of a planetary atmosphere. The observed occultation depth can be translated into a geometric albedo. This in turn aids in characterising the structure and composition of an atmosphere by providing additional information on the wavelength-dependent reflective qualities of the aerosols in the atmosphere. Aims. Our aim is to provide a precise measurement of the geometric albedo of the gas giant HD 189733b by measuring the occultation depth in the broad optical bandpass of CHEOPS (350 - 1100 nm). Methods. We analysed 13 observations of the occultation of HD 189733b performed by CHEOPS utilising the Python package PyCHEOPS. The resulting occultation depth is then used to infer the geometric albedo accounting for the contribution of thermal emission from the planet. We also aid the analysis by refining the transit parameters combining observations made by the TESS and CHEOPS space telescopes. Results. We report the detection of an $24.7 \pm 4.5$ ppm occultation in the CHEOPS observations. This occultation depth corresponds to a geometric albedo of $0.076 \pm 0.016$. Our measurement is consistent with models assuming the atmosphere of the planet to be cloud-free at the scattering level and absorption in the CHEOPS band to be dominated by the resonant Na doublet. Taking into account previous optical-light occultation observations obtained with the Hubble Space Telescope, both measurements combined are consistent with a super-stellar Na elemental abundance in the dayside atmosphere of HD 189733b. We further constrain the planetary Bond albedo to between 0.013 and 0.42 at 3$\sigma$ confidence.

A general formulation is developed to demonstrate that atomic autoionizing (AI) resonances are broadened and shifted significantly due to plasma effects across bound-free continua. The theoretical and computational method presented accounts for broadening mechanisms: electron collisional, ion microfields (Stark), thermal Doppler, core excitations, and free-free transitions. {\it Extrinsic} plasma broadening redistributes and shifts AI resonance strengths while broadly preserving naturally {\it intrinsic} asymmetries of resonance profiles. Integrated oscillator strengths are conserved as resonance structures dissolve into continua with increasing electron density. As exemplar, the plasma attenuation of photoionization cross sections computed using the R-matrix method is studied in neon-like Fe~XVII in a critical range $N_e = 10^{21-24}$cc along isotherms $T = 1-2 \times 10^6$K, and its impact on Rosseland Mean opacities. The energy-temperature-density dependent cross sections would elicit and introduce physical features in resonant processes in photoionization, \eion excitation and recombination. The method should be generally applicable to atomic species in high-energy-density (HED) sources such as fusion plasmas and stellar interiors.

Being the backbone element of DNA, phosphorus is a key component in the search for life in the Universe. To aid in its detection, we present line emissivity ratios for the five lowest-lying forbidden [P~II] transitions, namely those among the levels $3s^23p^2(^3P_0,^3P_1, ^3P_2,^1D_2,^1S_0)$. The wavelengths range between 0.44-70 \mum, and several lie within the spectroscopic domain observable with the James Webb Space Telescope (JWST). These line ratios have been calculated using a new collisional-radiative-recombination (CRR) model combining calculated collision strengths and level-specific recombination rate coefficients; with both datasets computed using the accurate Breit-Pauli R-Matrix method. The CRR model includes a new scheme for \eion recombination to emission line formation. We compare its effect to models incorporating only electron impact excitation and spontaneous radiative decay. We find that electron-ion recombination has a significant impact on all line ratios, and represents a major improvement in physical accuracy of emission line models.

We study the relation between the metallicities of ionised and neutral gas in star-forming galaxies at z=1-3 using the EAGLE cosmological, hydrodynamical simulations. This is done by constructing a dense grid of sightlines through the simulated galaxies and obtaining the star formation rate- and HI column density-weighted metallicities, Z_{SFR} and Z_{HI}, for each sightline as proxies for the metallicities of ionised and neutral gas, respectively. We find Z_{SFR} > Z_{HI} for almost all sightlines, with their difference generally increasing with decreasing metallicity. The stellar masses of galaxies do not have a significant effect on this trend, but the positions of the sightlines with respect to the galaxy centres play an important role: the difference between the two metallicities decreases when moving towards the galaxy centres, and saturates to a minimum value in the central regions of galaxies, irrespective of redshift and stellar mass. This implies that the mixing of the two gas phases is most efficient in the central regions of galaxies where sightlines generally have high column densities of HI. However, a high HI column density alone does not guarantee a small difference between the two metallicities. In galaxy outskirts, the inefficiency of the mixing of star-forming gas with HI seems to dominate over the dilution of heavy elements in HI through mixing with the pristine gas. We find good agreement between the limited amount of available observational data and the Z_{SFR}-Z_{HI} relation predicted by the EAGLE simulations, but more data is required for stringent tests.

Spectroscopic studies of extreme-ionization galaxies (EIGs) are critical to our understanding of exotic systems throughout cosmic time. These EIGs exhibit spectral features requiring >54.42 eV photons: the energy needed to fully ionize helium into He2+ and emit He II recombination lines. They are likely key contributors to reionization, and they can also probe exotic stellar populations or accretion onto massive black holes. To facilitate the use of EIGs as probes of high ionization, we focus on ratios constructed from strong rest-frame UV/optical emission lines, specifically [O III] 5008, H-beta, [Ne III] 3870, [O II] 3727,3729, and [Ne V] 3427. These lines probe the relative intensity at energies of 35.12, 13.62, 97.12, 40.96, and 13.62 eV, respectively, covering a wider range of ionization than traced by other common rest-frame UV/optical techniques. We use ratios of these lines ([Ne V]/[Ne III] = Ne53 and [Ne III]/[O II]), which are closely separated in wavelength, and mitigates effects of dust attenuation and uncertainties in flux calibration. We make predictions from photoionization models constructed from Cloudy that use a broad range of stellar populations and black hole accretion models to explore the sensitivity of these line ratios to changes in the ionizing spectrum. We compare our models to observations from the Hubble Space Telescope and James Webb Space Telescope of galaxies with strong high-ionization emission lines at z ~ 0, z ~ 2, and z ~ 7. We show that the Ne53 ratio can separate galaxies with ionization from 'normal' stellar populations from those with AGN and even 'exotic' Population III models. We introduce new selection methods to identify galaxies with photoionization driven by Population III stars or intermediate-mass black hole accretion disks that could be identified in upcoming high-redshift spectroscopic surveys.

Very long baseline interferometry (VLBI) observations show that some active galactic nuclei (AGN) jets exhibit bending even at parsec scales. The nature of bending is comprehensively analysed only for a small number of individual AGN, and the overall trends in shape of the substantially curved jets are unclear. In this work, we analyse outflows in AGN on the basis of publicly available multi-frequency VLBI images. Nearly 73000 images of about 11000 AGN are studied. Our research reveals that about 5% of them show a significantly curved jet structure. We characterize the jets geometry by fitting total intensity ridge lines constructed at all available frequencies and epochs with a set of simple models and suggest possible scenarios explaining the observed bending.

Using data from the GOTHAM (GBT Observations of TMC-1: Hunting for Aromatic Molecules) survey, we report the first astronomical detection of the C10H- anion. The astronomical observations also provided the necessary data to refine the spectroscopic parameters of C10H-. From the velocity stacked data and the matched filter response, C10H- is detected at >9{\sigma} confidence level at a column density of 4.04e11 cm-2. A dedicated search for the C10H radical was also conducted towards TMC-1. In this case, the stacked molecular emission of C10H was detected at a ~3.2{\sigma} confidence interval at a column density of 2.02e11 cm-2. However, since the determined confidence level is currently <5{\sigma}, we consider the identification of C10H as tentative. The full GOTHAM dataset was also used to better characterize the physical parameters including column density, excitation temperature, linewidth, and source size for the C4H, C6H and C8H radicals and their respective anions, and the measured column densities were compared to the predictions from a gas/grain chemical formation model and from a machine learning analysis. Given the measured values, the C10H-/C10H column density ratio is ~2.0 - the highest value measured between an anion and neutral species to date. Such a high ratio is at odds with current theories for interstellar anion chemistry. For the radical species, both models can reproduce the measured abundances found from the survey; however, the machine learning analysis matches the detected anion abundances much better than the gas/grain chemical model, suggesting that the current understanding of the formation chemistry of molecular anions is still highly uncertain.

The current observational status of the hot (log T(K) > 5.5) warm-hot intergalactic medium (WHIM) remains incomplete. While recent observations from stacking large numbers of Cosmic Web filaments have yielded statistically significant detections, direct measurements of single objects remain scarce. The lack of such a sample currently prevents a robust analysis of the cosmic baryon content composed of the hot WHIM, which could help solve the cosmological missing baryons problem. To improve the search for the missing baryons, we used the EAGLE simulation. Our aim is to understand the metal enrichment and distribution of highly ionised metals in the Cosmic Web. We detected the filaments by applying the Bisous formalism to the simulated galaxies, and characterised the spatial distributions as well as mass and volume fractions of the filamentary oxygen and OVII. We then constructed OVII column density maps and determined their detectability with Athena X-IFU. However, the oxygen and OVII number densities drop fast beyond the virial radii of haloes, falling below detectable levels at 700 kpc. Thus, only ~1% of the filament volumes are filled with OVII at detectable densities. This non-homogeneous distribution of the OVII complicates its usage for tracing the missing baryons. Instead, OVII forms narrow envelopes around haloes. This localised nature results in a low chance (10-20% per sight line) of detecting intergalactic OVII with Athena X-IFU within the SDSS catalogue of filaments. With future filament samples from the 4MOST survey, the chances increase up to a level of ~50%. Nonetheless, based on EAGLE results, this would not be enough to conclusively solve the missing baryon problem, as it would be limited to a few times the virial radii of haloes. Fortunately, the volumes around haloes are dense in hot WHIM, and tracing it could reduce the content of baryons still missing by ~25%.

We present the detection and analysis of the full-orbit phase curve and secondary eclipse of the short-period transiting hot Jupiter system WASP-19b with a single joint fit to photometric data and resolve parameter degeneracy. We analyze data taken by the Transiting Exoplanet Survey Satellite (TESS) during sectors 9 and 36.

The study of compact object populations has come a long way since the determination of the mass of the Hulse-Taylor pulsar, and we now count on more than 150 known Galactic neutron stars and black hole masses, as well as another 180 objects from binary mergers detected from gravitational-waves by the Ligo-Virgo-KAGRA Collaboration. With a growing understanding of the variety of systems that host these objects, their formation, evolution and frequency, we are now in a position to evaluate the statistical nature of these populations, their properties, parameter correlations and long-standing problems, such as the maximum mass of neutron stars and the black hole lower mass gap, to a reasonable level of statistical significance. Here, we give an overview of the evolution and current state of the field and point to some of its standing issues. We focus on Galactic black holes, and offer an updated catalog of 35 black hole masses and orbital parameters, as well as a standardized procedure for dealing with uncertainties.

We describe the first grid-based simulations of the polar alignment of a circumbinary disk. We simulate the evolution of an inclined disk around an eccentric binary using the grid-based code ATHENA++. The use of a grid-based numerical code allows us to explore lower disk viscosities than have been examined in previous studies. We find that the disk aligns to a polar orientation when the $\alpha$ viscosity is high, while disks with lower viscosity nodally precess with little alignment over 1000 binary orbital periods. The timescales for polar alignment and disk precession are compared as a function of disk viscosity, and are found to be in agreement with previous studies. At very low disk viscosities (e.g. $\alpha = 10^{-5}$), anticyclonic vortices are observed along the inner edge of the disk. These vortices can persist for thousands of binary orbits, creating azimuthally localized overdensities as well as multiple pairs of spiral arms. The vortex is formed at $\sim 3-4$ times the binary semi-major axis, close to the inner edge of the disk, and orbits at roughly the local Keplerian speed. The presence of a vortex in the disk may play an important role in the evolution of circumbinary systems, such as driving episodic accretion and accelerating the formation of polar circumbinary planets.

Context. It is well-established that shock waves in the intracluster medium launched by galaxy cluster mergers can produce synchrotron emission, which is visible to us at radio frequencies as radio relics. However, the particle acceleration mechanism producing these relics is still not fully understood. It is also unclear how relics relate to radio halos, which trace merger-induced turbulence in the intracluster medium. Aims. We aim to perform the first statistical analysis of radio relics in a mass-selected sample of galaxy clusters, using homogeneous observations. Methods. We analysed all relics observed by the Low Frequency Array Two Metre Sky Survey Data Release 2 (LoTSS DR2) at 144 MHz, hosted by galaxy clusters in the second Planck catalogue of SZ sources (PSZ2). We measured and compared the relic properties in a uniform, unbiased way. In particular, we developed a method to describe the characteristic downstream width in a statistical manner. Additionally, we searched for differences between radio relic-hosting clusters with and without radio halos. Results. We find that, in our sample, $\sim$ 10% of galaxy clusters host at least one radio relic. We confirm previous findings, at higher frequencies, of a correlation between the relic-cluster centre distance and the longest linear size, as well as the radio relic power and cluster mass. However, our findings suggest that we are still missing a population of low-power relics. We also find that relics are wider than theoretically expected, even with optimistic downstream conditions. Finally, we do not find evidence of a single property that separates relic-hosting clusters with and without radio halos.

We study the internal and external alignment of carbonaceous grains, including graphite and hydrogenated amorphous carbon (HAC), in the interstellar medium (ISM) within the RAdiative Torque (RAT) paradigm. For internal alignment (IA), we find that HAC grains having nuclear paramagnetism due to hydrogen protons can have efficient nuclear relaxation, whereas both HAC and graphite grains can have efficient inelastic relaxation for grains aligned both at low$-J$ and high$-J$ attractors. For external alignment, HAC and graphite grains can align with the radiation direction ($k$-RAT) at low$-J$ attractors but cannot have stable alignment at high$-J$ attractors due to the suppression of radiative precession. HAC also has slow Larmor precession compared to the randomization by gas collisions and cannot be aligned with the magnetic field ($B$-RAT). Small HAC grains of $a<0.05\mu$m drifting through the diffuse ISM can be weakly aligned along the induced electric field ($E$-RAT) at high$-J$ attractors due to its fast precession. Paramagnetic relaxation by nuclear magnetism is found inefficient for HAC grains due to the rapid suppression of nuclear susceptibility when grains rotate at high$-J$ attractors. We then study the alignment of carbon dust in the envelope of a typical C-rich Asymptotic Giant Branch star, IRC+10216. We find that grains aligned at low$-J$ attractors can occur via $k$-RAT with the wrong IA in the inner region but via $B$-RAT in the outermost region. However, grains aligned at high$-J$ attractors have the right IA alignment via $k$-RAT due to efficient inelastic relaxation. The polarization pattern observed toward IRC+10216 by SOFIA/HAWC+ can reproduced when only grains at low$-J$ attractors are present due to removal of grains at high$-J$ attractors by the RAT disruption.

Understanding the dynamics of the quiet solar corona is important for answering key questions including the coronal heating problem. Multiple studies have suggested small-scale magnetic reconnection events may play a crucial role. These reconnection events are expected to involve accelerating electrons to suprathermal energies, which can then produce nonthermal observational signatures. However, due to the paucity of sensitive high-fidelity observations capable of probing these nonthermal signatures, most studies were unable to quantify their nonthermal nature. Here we use joint radio observations from the Very Large Array (VLA) and the Expanded Owens Valley Solar Array (EOVSA) to detect transient emissions from the quiet solar corona in the microwave (GHz) domain. While similar transients have been reported in the past, their nonthermal nature could not be adequately quantified due to the unavailability of broadband observations. Using a much larger bandwidth available now with the VLA and EOVSA, in this study, we are able to quantify the nonthermal energy associated with two of these transients. We find that the total nonthermal energy associated with some of these transients can be comparable to or even larger than the total thermal energy of a nanoflare, which underpins the importance of nonthermal energy in the total coronal energy budget.

We present results of the spectroscopic study of the chemically peculiar star BD+30$^\circ$549 which is bona-fide member of young NGC 1333 star forming region. We found that the star possesses negligible rotation and helium-weak spectroscopic pattern with strongly enhanced Si II and Si III lines. The fundamental parameters of the star $T_{eff}$=13100~K and $\log (L/L_{\odot})$=2.1 indicate its age of about 2.7 Myr and position on the Hertzsprung-Russell diagram at the end of the Pre-Main Sequence evolutionary track, close to the Zero Age Main Sequence. Abundance analysis reveals the modest deficit of almost all elements with exception of Si, Fe, Ca and P which are overabundant. We performed the non-LTE calculations for Si II/Si III, Mg II and Ca II in order to check the influence of departures from LTE on line formation. Non-LTE calculations lead to much better reproduction of individual silicon line profiles, but does not completely remove the abundance discrepancy between Si II and Si III lines. We also investigate the effects of possible chemical stratification in BD+30$^\circ$549. We suspect that the "Si II/Si III anomaly", observed in BD+30$^\circ$549 spectrum arises under the combined action of the vertical and horizontal abundance gradients and non-LTE effects. We suppose that evolutionary status and phenomena observed in BD+30$^\circ$549 indicate that conditions favorable for the selective diffusion and formation of the surface chemical composition peculiarities (slow rotation and stabilization of the atmosphere) can be built up already at the Pre-Main Sequence phase.

Telescope arrays are receiving increasing attention due to their promise of higher resource utilization, greater sky survey area, and higher frequency of full space-time monitoring than single telescopes. Compared with the ordinary coordinated operation of several telescopes, the new astronomical observation mode has an order of magnitude difference in the number of telescopes. It requires efficient coordinated observation by large-domain telescopes distributed at different sites. Coherent modeling of various abstract environmental constraints is essential for responding to multiple complex science goals. Also, due to competing science priorities and field visibility, how the telescope arrays are scheduled for observations can significantly affect observation efficiency. This paper proposes a multilevel scheduling model oriented toward the problem of telescope-array scheduling for time-domain surveys. A flexible framework is developed with basic functionality encapsulated in software components implemented on hierarchical architectures. An optimization metric is proposed to self-consistently weight contributions from time-varying observation conditions to maintain uniform coverage and efficient time utilization from a global perspective. The performance of the scheduler is evaluated through simulated instances. The experimental results show that our scheduling framework performs correctly and provides acceptable solutions considering the percentage of time allocation efficiency and sky coverage uniformity in a feasible amount of time. Using a generic version of the telescope-array scheduling framework, we also demonstrate its scalability and its potential to be applied to other astronomical applications.

We present 12CO (J=2-1) sensitive molecular line and 1.3 mm continuum observations made with the Submillimeter Array (SMA) of the bipolar outflow associated with the young star located in the Bok globule known as CB 26. The SMA observations were carried out in its extended configuration allowing us to study the kinematics and structure of the outflow with about 1 arcsec or 140 au resolution. We find that the dusty and edge-on circumstellar disk related with the outflow has an projected spatial (deconvolved) size of 196 au x 42 au with a total (gas and dust) mass of 0.031 Msun. We estimated a dynamical mass for the central object of 0.66 Msun, and the mass of the molecular outflow of 5x10-5 Msun. The observations confirm that the outflow rotation has a similar orientation to that of the edge-on disk. For the outflow, we find that the following quantities: the rotation velocity, the specific angular momentum, and the launching radius, decrease with the height above mid-plane, as observed in other molecular rotating outflows. The radius, and expansion velocity also increase with the height above the disk midplane. Estimations for the outflow linear momentum rate, the outflow angular momentum rate, and the accretion luminosity seem to be well explained by a disk wind present in CB26.

The shearing motion of tidal flows that are excited in non-equilibrium binary stars transform kinetic energy into heat via a process referred to as tidal heating. In this paper we aim to explore the way tidal heating affects the stellar structure. We used the TIDES code, which solves the equations of motion of the three-dimensional (3D) grid of volume elements that conform multiple layers of a rotating binary star to obtain an instantaneous value for the angular velocity, $\omega''$, as a function of position in the presence of gravitational, centrifugal, Coriolis, gas pressure, and viscous forces. The released energy, $\dot{E,}$ was computed using a prescription for turbulent viscosity that depends on the instantaneous velocity gradients. The $\dot{E}$ values for each radius were injected into a MESA stellar structure calculation. The method is illustrated for a 1.0+0.8 M$_\odot$ binary system, with an orbital period of $P$=1.44d and departures from synchronous rotation of 5% and 10%. We find that heated models have a larger radius and surface luminosity, a smaller surface convection zone, and lower nuclear reaction rates than the equivalent standard stellar models, and their evolutionary tracks extend to higher temperatures. The magnitude of these effects depends on the amount of injected energy, which, for a fixed set of stellar, rotation and orbital parameters, depends on the perturbed star's density structure and turbulent viscosity. Tidal heating offers a possible alternative for describing phenomena such as bloated or overluminous binary components, age discrepancies, and aspherical mass ejection, as well as the extended main sequence turnoff in clusters. However, establishing its actual role requires 3D stellar structure models commensurate with the nonspherically symmetric properties of tidal perturbations.

Modification of general relativity (GR) inspired by theories like $f(R)$ gravity is among the most popular ones to explain the late-time acceleration of the Universe as an alternative to the $\Lambda$CDM model. In this work, we use the state-of-the-art BAO+BBN data and the most recent Type Ia supernovae (SNe Ia) sample namely PantheonPlus, including the Cepheid host distances and covariance from SH0ES samples, to robustly constrain the $f(R)$ gravity framework via two of the most popular $f(R)$ models in literature, namely, the Hu-Sawicki and Starobinsky models. Additionally, we consider how the time variation of the Newton's gravitational constant affects the supernovae distance modulus relation. We find a minor evidence for $f(R)$ gravity under the Hu-Sawicki dynamics from BAO+BBN and BAO+BBN+uncalibrated supernovae joint analysis, but the inclusion of Cepheid host distances, makes the model compatible with GR. Further, we notice tendency of this model to relax the $H_0$ tension. In general, in all the analyses carried out in this study with the late time probes, we find both the $f(R)$ models to be consistent with GR at 95\% CL.

We present polarization-sensitive images from the Karl G. Jansky Very Large Array (VLA) at 5~GHz of 11 radio-quiet PG quasars. Based on the radio morphology, spectral index and polarization properties from the VLA study, coupled with the findings of previous 685~MHz uGMRT data, we find evidence for bent and low-powered jets on milli or sub-arcsec and arcsec scales in 8 sources. We cannot determine the origin of radio emission (between jet/AGN wind/starburst wind) with the current data in the remaining 3 sources. Of the 11 sources, linear polarization is detected in four of them. The fractional polarization in them ranges between 2\% to 25\%. In PG~0050+124 and PG~1229+204, the inferred B-field direction is parallel to the local kpc-scale jet direction. Very Long Baseline Array (VLBA) data on PG~0050+124 indicates that the jet changes its direction from pc- to kpc-scales in this source. For PG~0923+129, the relationship between its B-field direction and radio outflow direction remains unclear. PG~0934+013 exhibits transverse inferred B-fields at the base of its kpc-scale jet. While there appears to be no evidence in the literature for global signatures of `AGN feedback' in this sample such as reduced molecular gas content or star-formation, scenarios like localised AGN feedback or a preliminary phase of AGN feedback, cannot be ruled out. Differences in the time-scales of gas outflows and AGN activity could also play a role. In addition, the galactic merger scenario could influence the overall interpretation of AGN feedback in these sources, given that the host galaxies in a large fraction of them show signatures of ongoing galactic mergers.

We study the imprints of a cosmological redshift-dependent pseudoscalar field $\phi$ on the rotation of cosmic microwave background (CMB) linear polarization generated by a coupling $ \phi F^{\mu\nu} \tilde F_{\mu \nu}$. We show how either phenomenological or theoretically motivated redshift dependence of the pseudoscalar field, such as those in models of Early Dark Energy, Quintessence or axion-like dark matter, lead to CMB polarization and temperature-polarization power spectra which exhibit a multipole dependence which goes beyond the widely adopted approximation in which the redshift dependence of the linear polarization angle is neglected. Because of this multipole dependence, the isotropic birefringence effect due to a general coupling $\phi F^{\mu\nu} \tilde F_{\mu \nu}$ is not degenerate with a systematic calibration angle uncertainty. By taking this multipole dependence into account, we calculate the parameters of these phenomenological and theoretical redshift dependence of the pseudoscalar field which can be detected by future CMB polarization experiments on the basis of a $\chi^2$ analysis for a Wishart likelihood. As a final example of our approach, we compute by Markov Chain MonteCarlo (MCMC) the minimal coupling $g_\phi$ in Early Dark Energy which could be detected by future experiments, with or without marginalizing on a systematic rotation angle uncertainty.

To solve some problems of celestial mechanics and astrophysics, three new models of an elliptical galaxy (EG) have been created, which are in good agreement with modern understanding of the structure of such galaxies. Based on these models, the total gravitational (potential) energy and rotational kinetic energy of an EG, as well as the velocity dispersion at a distance of its effective radius, are determined. A new method is proposed for determining the average values of the scale radius of an EG and the density at its center, as well as the average value of its key parameter density $\beta$ and its value at a distance corresponding to the effective radius of the galaxy. The results obtained are applied to sixty EGs and presented in the form of tables for ten galaxies.

The problem of the spatial motion of a passively gravitating body (PGB) in the gravitational field of a layered inhomogeneous elliptical galaxy (LIEG) is considered on the basis of the previously developed model. It is assumed that a LIEG consists of baryonic mass (BM) and dark matter (DM), which have different laws of density distribution. A star or the center of mass of a globular cluster is taken as the PGB, the motion of which considers the BM and DM attraction. To obtain accurate results, the BM and DM attraction potentials are not expanded in a series, but their exact expressions are taken. An analogue of the Jacobi integral is found, the region of the possible motion of the PGB is determined, and the zero-velocity surfaces are constructed. The stationary solutions (libration points) are found to be stable in the sense of Lyapunov. The results are applied to the elliptical galaxies NGC 4472 (M 49), NGC 4697, and NGC 4374 (M 84).

Detailed knowledge of surface dynamics is one of the key points in understanding magnetic solar activity. The motions of the solar surface, to which we have direct access via the observations, tell us about the interaction between the emerging magnetic field and the turbulent fields. The flows computed with the coherent structure tracking (CST) technique on the whole surface of the Sun allow for the texture of the velocity modulus to be analyzed and for one to locate the largest horizontal flows and determine their organization. The velocity modulus maps show structures more or less circular and closedwhich are visible at all latitudes; here they are referred to as donuts. They reflect the most active convective cells associated with supergranulation. These annular flows are not necessarily joined as would seem to indicate the divergence maps. The donuts have identical properties (amplitude, shape, inclination, etc.) regardless of their position on the Sun. The kinematic simulation of the donuts' outflow applied to passive scalar (corks) indicates the preponderant action of the selected donuts which are, from our analysis, one of the major actors for the magnetic field diffusion on the quiet Sun. The absence of donuts in the magnetized areas (plages) indicates the action of the magnetic field on the strongest supergranular flows and thus modifies the diffusion of the magnetic field in that location. The detection of the donuts is a way to locate in the quiet Sun the vortex and the link with the jet, blinkers, coronal bright points (campfires), or other physical structures. Likewise, the study of the influence of donuts on the evolution of active events, such as the destruction of sunspots, filament eruptions, and their influences on upper layers via spicules and jets, could be done more efficiently via the detection of that structures.

We report the first observations of simultaneous large-amplitude longitudinal and transverse oscillations of a quiescent filament trigged by a two-sided-loop jet formed by the magnetic reconnection between the filament and an emerging loop in the filament channel, recorded by the Solar Dynamics Observatory and the Solar TErrestrial RElations Observatory. The north arm of the jet firstly pushed the filament mass moving northwardly along the magnetic field lines consisting of the coronal cavity, then some elevated filament mass fell back and started to oscillate longitudinally at the bottom of the cavity (i.e., the magnetic dip). The northernmost part of the filament also showed transverse oscillation simultaneously. The amplitude and period of the longitudinal (transverse) oscillation are 12.96 (2.99) Mm and 1.18 (0.33) hours, respectively. By using the method of filament seismology, the radius of curvature of the magnetic dip is about 151 Mm, consistent with that obtained by the 3D reconstruction (166 Mm). Using different physical parameters of the observed longitudinal and transverse oscillations, the magnetic field strength of the filament is estimated to be about 23 and 21 Gauss, respectively. By calculating the energy of the moving filament mass, the minimum energy of the jet is estimated to be about 1.96 x 10^28 erg. We conclude that the newly formed jet can not only trigger simultaneous longitudinal and transverse oscillations in a single filament, but also can be used as a seismology tool for diagnosing filament information, such as the magnetic structure, magnetic field strength, and magnetic twists.

The formation of the extended thin disc is the most spectacular event of our Galaxy in the past $\sim8$\,Gyr. To unveil this process, obtaining precise and accurate stellar ages for a large sample of stars is essential although challenging. In this work, we present the asteroseismic age determination of 5306 red giant branch stars using \kepler{} and LAMOST data, with a thorough examination of how the age determination is affected by the choice of different temperature scales and stellar models. Thanks to the high precision of the asteroseismic and spectroscopic parameters of our sample stars, we are able to achieve age determination with an average accuracy of 12 per cent. However, the age determination is sensitively dependent on the adopted temperature scale, as 50\,K difference in effective temperature may cause larger than 10 per cent systematic uncertainty in the age estimates. Using the ages derived with the most plausible set of the temperature scale, we study the age distribution of the chemical thin disc stars, and present an estimate of the formation epoch of the first Galactic thin disc stars. We find that the first (oldest) thin disc stars have an age of $9.5^{+0.5(\rm rand.)+0.5(\rm sys.)}_{-0.4(\rm rand.)-0.3(\rm sys.)}$\,Gyr, where the systematic uncertainties reflect ages estimated using different stellar evolutionary models. At this epoch, the Galactic thick disc was still forming stars, indicating there is a time window when both the thin and thick discs of our Galaxy were forming stars together. Moreover, we find that the first thin disc stars exhibit a broad distribution of Galactocentric radii, suggesting that the inner and outer thin discs began to form simultaneously.

We have carried out the NH$_3$ $(J,K)=(1,1),(2,2),$ and $(3,3)$ mapping observations toward the Galactic infrared bubble N49 (G28.83-0.25) using the Nobeyama 45 m telescope. Three NH$_3$ clumps (A, B, and C) were discovered along the molecular filament with the radial velocities of $\sim$ 96, 87, and 89 km s$^{-1}$, respectively. The kinetic temperature derived from the NH$_3$ (2,2)/NH$_3$ (1,1) shows $T_{\rm kin} = 27.0 \pm 0.6$ K enhanced at Clump B in the eastern edge of the bubble, where position coincides with massive young stellar objects (MYSOs) associated with the 6.7 GHz class II methanol maser source. This result shows the dense clump is locally heated by stellar feedback from the embedded MYSOs. The NH$_3$ Clump B also exists at the 88 km s$^{-1}$ and 95 km s$^{-1}$ molecular filament intersection. We therefore suggest that the NH$_3$ dense gas formation in Clump B can be explained by a filament-filament interaction scenario. On the other hand, NH$_3$ Clump A and C at the northern and southern side of the molecular filament might be the sites of spontaneous star formation because these clumps are located $\sim$5$-$10 pc away from the edge of the bubble.

Dynamically linking a meteor shower with its parent body can be challenging. This is in part due to the limit of today's tools (such as D-criteria) and in part due to the complex dynamics of meteoroid streams. We choose a method to study chaos in meteoroid streams and apply it to the Geminid meteoroid stream. We decide to draw chaos maps. We show that the Orthogonal Fast Lyapunov Indicator is well-suited to our problem, amongst the chaos indicator we studied. The maps are drawn for three size bins, ranging from $10^{-1}$ to $10^{-4}$ m. We show the influence of mean-motion resonances with the Earth and with Venus, which tend to trap the largest particles. The chaos maps present 3 distinct regimes in eccentricity, reflecting close encounters with the planets. We also study the effect of non-gravitational forces. We determine a first approximation of the particle size $r_{lim}$ needed to counterbalance the resonances with the diffusion due to the non-gravitational forces. We find that, for the Geminids, $r_{lim}$ lies in the range $[3;8]\times 10^{-4}$ m. However, $r_{lim}$ depends on the orbital phase space.

Diffuse gamma-ray emission from the decay of radioactive $^{26}$Al is a messenger from the nucleosynthesis activity in our current-day galaxy. Because this material is attributed to ejections from massive stars and their supernovae, the gamma-ray signal includes information about nucleosynthesis in massive star interiors as it varies with evolutionary stages, and about their feedback on the surrounding interstellar medium. Our method of population synthesis of massive-star groups has been refined as a diagnostic tool for this purpose. It allows to build a bottom-up prediction of the diffuse gamma-ray sky when known massive star group distributions and theoretical models of stellar evolution and core-collapse supernova explosions are employed. We find general consistency of an origin in such massive-star groups, in particular we also find support for the clumpy distribution of such source regions across the Galaxy, and characteristics of large cavities around these. A discrepancy in the integrated $^{26}$Al gamma-ray flux is interpreted as an indication for excess $^{26}$Al emission from nearby, distributed in cavities that extend over major regions of the sky.

Based on a comparison of the SRG/eROSITA catalog of X-ray active stars and the Gaia catalog, a sample of 502 peculiar objects was obtained for which Gaia, on one hand, detects statistically significant values of parallax or proper motion and, on the other hand, registers signs of the non zero source extent in the optical band. In the log ($F_X/F_{\rm opt}$) - (G-RP) color diagram these objects are separated from the balk of X-ray active stars and are located in the region typical for the galaxies with active nuclei. According to the SIMBAD database, about $\sim 50$% of them are confirmed AGNs and galaxies with spectroscopically measured redshifts, and only $\sim$1.4% are confirmed Galactic objects. Spectroscopic observations of 19 unidentified objects on the RTT-150 telescope demonstrated, that 18 of them are AGNs at redshifts $\sim$0.01-0.3, and one object is a M star in our Galaxy. We discuss various scenarios explaining the nature of such peculiar objects.

Knowledge of stellar atmospheric parameters ($T_{\rm eff}$, $\log{g}$, [Fe/H]) of M dwarfs can be used to constrain both theoretical stellar models and Galactic chemical evolutionary models, and guide exoplanet searches, but their determination is difficult due to the complexity of the spectra of their cool atmospheres. In our ongoing effort to characterize M dwarfs, and in particular their chemical composition, we carried out multiband photometric calibrations of metallicity for early- and intermediate-type M dwarfs. The third Gaia data release provides high-precision astrometry and three-band photometry. This information, combined with the 2MASS and CatWISE2020 infrared photometric surveys and a sample of 4919 M dwarfs with metallicity values determined with high-resolution spectroscopy by The Cannon and APOGEE spectra, allowed us to study the effect of the metallicity in color-color and color-magnitude diagrams. We divided this sample into two subsamples: we used 1000 stars to train the calibrations with Bayesian statistics and Markov Chain Monte Carlo techniques, and the remaining 3919 stars to check the accuracy of the estimations. We derived several photometric calibrations of metallicity applicable to M dwarfs in the range of $-0.45\leq\text{[Fe/H]}\leq +0.45$ dex and spectral types down to M5.0 V that yield uncertainties down to the $0.10$ dex level. Lastly, we compared our results with other photometric estimations published in the literature for an additional sample of 46 M dwarfs in wide binary systems with FGK-type primary stars, and found a great predictive performance.

Aims: The aim of this work is to develop a method to systematically detect and characterise fast-time variations ($\gtrsim 1$s) in the non-thermal hard X-ray (HXR) time profiles of solar flares using high-resolution data from Solar Orbiter's Spectrometer/Telescope for Imaging X-rays (STIX). Methods: The HXR time profiles were smoothed using Gaussian Process (GP) regression. The time profiles were then fitted with a linear combination of Gaussians to decompose the time profile. From the Gaussian decomposition, key characteristics such as the periodicity, full width at half maximum (FWHM), time evolution, and amplitude can be derived. Results: We present the outcome of applying this method to four M and X GOES-class flares from the first year of Solar Orbiter science operations. The HXR time profiles of these flares were decomposed into individual Gaussians and their periods were derived. The quality of fit is quantified by the standard deviation of the residuals (difference between observed and fitted curve, normalised by the error on the observed data), for which we obtain $\leq 1.8$ for all flares presented. In this work, the first detection of fast-time variations with Solar Orbiter's STIX instrument has been made on timescales across the range of 4-128s. Conclusions: A new method for identifying and characterising fast-time variations in the non-thermal HXR profiles of solar flares has been developed, in which the time profiles are fit with a linear combination of Gaussian bursts. The opportunity to study time variations in flares has greatly improved with the new observations from STIX on Solar Orbiter.

The bright polarized synchrotron emission, away from the Galactic plane, originates mostly from filamentary structures. We implement a filament finder algorithm which allows the detection of bright elongated structures in polarized intensity maps. We analyse the sky at 23 and 30~GHz as observed respectively by \textit{WMAP} and \textit{Planck}. We identify 19 filaments, 13 of which have been previously observed. For each filament, we study the polarization fraction, finding values typically larger than for the areas outside the filaments, excluding the Galactic plane, and a fraction of about 30\% is reached in two filaments. We study the polarization spectral indices of the filaments, and find a spectral index consistent with the values found in previous analysis (about -3.1) for more diffuse regions. Decomposing the polarization signals into the $E$ and $B$ families, we find that most of the filaments are detected in $P_E$, but not in $P_B$. We then focus on understanding the statistical properties of the diffuse regions of the synchrotron emission at 23~GHz. Using Minkowski functionals and tensors, we analyse the non-Gaussianity and statistical isotropy of the polarized intensity maps. For a sky coverage corresponding to 80\% of the fainter emission, and on scales smaller than 6 degrees ($\ell > 30$), the deviations from Gaussianity and isotropy are significantly higher than 3$\sigma$. The level of deviation decreases for smaller scales, however, it remains significantly high for the lowest analised scale ($\sim 1.5^\circ$). When 60\% sky coverage is analysed, we find that the deviations never exceed 3$\sigma$. Finally, we present a simple data-driven model to generate non-Gaussian and anisotropic simulations of the synchrotron polarized emission. The simulations are fitted in order to match the spectral and statistical properties of the faintest 80\% sky coverage of the data maps.

The CRyogenic InfraRed Echelle Spectrograph (CRIRES) Upgrade project CRIRES$^{+}$ extended the capabilities of CRIRES. It transformed this VLT instrument into a cross-dispersed spectrograph to increase the wavelength range that is covered simultaneously by up to a factor of ten. In addition, a new detector focal plane array of three Hawaii 2RG detectors with a 5.3 $\mu$m cutoff wavelength replaced the existing detectors. Amongst many other improvements, a new spectropolarimetric unit was added and the calibration system has been enhanced. The instrument was installed at the VLT on Unit Telescope 3 at the beginning of 2020 and successfully commissioned and verified for science operations during 2021, partly remotely from Europe due to the COVID-19 pandemic. The instrument was subsequently offered to the community from October 2021 onwards. This article describes the performance and capabilities of the upgraded instrument and presents on sky results.

Diffuse cluster-scale synchrotron radio emission is discovered in an increasing number of galaxy clusters in the form of radio halos (RHs), probing the presence of relativistic electrons and magnetic fields in the intra-cluster medium. The favoured scenario to explain their origin is that they trace turbulent regions generated during cluster mergers where particles are re-accelerated. In this framework, RHs are expected to probe cluster dynamics and are predicted to be more frequent in massive systems. Statistical studies are important to study the connection of RHs with cluster dynamics and to constrain theoretical models. Furthermore, low-frequency surveys can shed light on the existence of RHs with very steep radio-spectra, a key prediction of turbulent models. We study the properties of RHs from clusters of the second catalog of Planck Sunyaev Zel'dovich detected sources that lie within the 5634 deg^2 covered by the second Data Release (DR2) of the LOFAR Two-meter Sky Survey. We find that the number of observed RHs, their radio flux density and redshift distributions are in line with what is expected in the framework of the re-acceleration scenario. In addition, the fraction of clusters with RHs increases with the cluster mass, confirming the leading role of the gravitational process of cluster formation in the generation of RHs. These models predict a large fraction of RHs with very steep spectrum in the DR2 Planck sample, this will be tested in future studies, yet a comparison of the occurrence of halos in GMRT and LOFAR samples indeed shows a larger occurrence of RHs at lower frequencies suggesting the presence of a number of very steep spectrum RH that is preferentially detected by LOFAR. Using morphological information we confirm that RHs are preferentially located in merging systems and that the fraction of newly LOFAR discovered RHs is larger in less disturbed systems.

The GRAVITY instrument has been revolutionary for near-infrared interferometry by pushing sensitivity and precision to previously unknown limits. With the upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) in GRAVITY+, these limits will be pushed even further, with vastly improved sky coverage, as well as faint-science and high-contrast capabilities. This upgrade includes the implementation of wide-field off-axis fringe-tracking, new adaptive optics systems on all Unit Telescopes, and laser guide stars in an upgraded facility. GRAVITY+ will open up the sky to the measurement of black hole masses across cosmic time in hundreds of active galactic nuclei, use the faint stars in the Galactic centre to probe General Relativity, and enable the characterisation of dozens of young exoplanets to study their formation, bearing the promise of another scientific revolution to come at the VLTI.

The supernova model discrimination capabilities of the WATCHMAN detector concept are explored. This cylindrical kilotonne-scale water Cherenkov detector design has been developed to detect reactor antineutrinos through inverse $\beta$-decay for non-proliferation applications but also has the ability to observe antineutrino bursts of core-collapse supernovae within our galaxy. Detector configurations with sizes ranging from 16 m to 22 m tank diameter and 10% to 20% PMT coverage are used to compare the expected observable antineutrino spectra based on the Nakazato, Vartanyan and Warren supernova models. These spectra are then compared to each other with a fixed event count of 100 observed inverse $\beta$-decay events and a benchmark supernova at 10 kpc distance from Earth. By comparing the expected spectra, each detector configuration's ability to distinguish is evaluated. This analysis then demonstrates that the detector design is capable of meaningful event discrimination (95+% accuracy) with 100 observed supernova antineutrino events in any configuration. Furthermore, a larger tank configuration can maintain this performance at 10 kpc distance and above, indicating that overall target mass is the main factor for such a detector's discrimination capabilities.

We present linear polarimetry for seven hydrogen-poor superluminous supernovae (SLSNe-I). For SN 2017gci, for which we present two epochs of spectropolarimetry at +3 d and +29 d post-peak in rest frame, accompanied by four epochs of imaging polarimetry up to +108 d. The spectropolarimetry at +3 d shows increasing polarisation degree P towards the redder wavelengths and exhibits signs of axial symmetry, but at +29 d P=0 throughout the spectrum implying that the photosphere of SN 2017gci evolved from a slightly aspherical configuration to a more spherical one in the first month post-peak. However, an increase of P to 0.5% at +55 d accompanied by a different orientation of the axial symmetry compared to +3 d implies the presence of additional sources of polarisation at this phase. The increase in polarisation is possibly caused by interaction with circumstellar matter as already suggested by a knee in the light curve and a possible detection of broad Ha emission. We also analysed the sample of all 16 SLSNe-I with polarimetry to date. The data taken during the early spectroscopic phase show consistently low P indicating spherical photospheres. No clear relation between the polarimetry and spectral phase was seen when the spectra resemble Type Ic SNe during the photospheric and nebular phases. The light curve decline rate also shows no clear relation with the polarisation properties. While only slow-evolving SLSNe-I have shown non-zero P, the fast-evolving ones have not been observed at sufficiently late times to conclude that none of them exhibit changing P. However, the four SLSNe-I with increasing polarisation degree also have irregular light curve declines. For up to half of them, the photometric, spectroscopic and polarimetric properties are affected by CSM interaction. As such CSM interaction clearly plays an important role in understanding the polarimetric evolution of SLSNe-I.

Extended radio sources in the sky require a dense sampling of short baselines to be properly imaged by interferometers. This problem arises in many areas of radio astronomy, such as in the study of galaxy clusters, which may host Mpc-scale diffuse synchrotron sources in the form of radio halos. In clusters where no radio halos are detected, owing to intrinsic absence of emission or extrinsic (instrumental and/or observational) effects, it is possible to determine upper limits. We consider a sample of Planck galaxy clusters from the Second Data Release of the LOFAR Two Meter Sky Survey (LoTSS-DR2) where no radio halos are detected. We use this sample to test the capabilities of LOFAR to recover diffuse extended emission and derive upper limits. Through the injection technique, we simulate radio halos with various surface brightness profiles. We then predict the corresponding visibilities and image them along with the real visibilities. This method allows us to test the fraction of flux density losses owing to inadequate uv-coverage and obtain thresholds at which the mock emission becomes undetectable by visual inspection. The dense uv-coverage of LOFAR at short spacings allows to recover $\gtrsim90\%$ of the flux density of targets with sizes up to $\sim 15'$. We find a relation that provides upper limits based on the image noise and extent (in terms of number of beams) of the mock halo. This relation can be safely adopted to obtain upper limits without injecting when artifacts introduced by the subtraction of the discrete sources are negligible in the central region of the cluster. Otherwise, the injection process and visual inspection of the images are necessary to determine more reliable limits. Through these methods, we obtain upper limits for 75 clusters to be exploited in ongoing statistical studies.

It has been recently recognized that the surface of sub-km asteroids in contact with the space environment is not fine-grained regolith but consists of centimeter to meter-scale rocks. Here we aim to understand how the rocky morphology of minor bodies react to the well known space erosion agents on the Moon. We deploy a neural network and map a total of ~130,000 fragmented boulders scattered across the lunar surface and visually identify a dozen different desintegration morphologies corresponding to different failure modes. We find that several fragmented boulder morphologies are equivalent to morphologies observed on asteroid Bennu, suggesting that these morphologies on the Moon and on asteroids are likely not diagnostic of their formation mechanism. Our findings suggest that the boulder fragmentation process is characterized by an internal weakening period with limited morphological signs of damage at rock scale until a sudden highly efficient impact shattering event occurs. In addition, we identify new morphologies such as breccia boulders with an advection-like erosion style. We publicly release the produced fractured boulder catalog along with this paper.

The Fornax galaxy cluster is an ideal nearby laboratory in which to study the impact of dense environments on the evolution of galaxies. The Fornax3D survey offers extended and deep integral-field spectroscopic observations for the brightest 33 galaxies within of virial radius of the Fornax cluster, obtained with the MUSE integral-field spectrograph, mounted on Unit Telescope 4 (Yepun) of ESO's Very Large Telescope in Chile. The Fornax3D data allowed us to reconstruct the formation of early-type galaxies in the cluster and to explore the link with spiral galaxies. Results have been published in 19 refereed papers since 2018. In this paper we review the broad goals of this campaign, its main results and the potential for future studies combining the MUSE data with the abundant multi-wavelength data coverage for Fornax.

Low Frequency QPOs (LFQPOs) have always been seen uniquely as a timing feature, with most models focused on reproducing only their timing behavior. Previously, the Accretion-Ejection Instability (AEI) predicted the existence of a more subtle effect on their energy spectrum. In the case of LMXB, that effect was deemed impossible to detect. While the AEI can be naturally expanded to higher-mass systems, there was no observational drive to do it until now. However the several (candidate) QPOs detected in supermassive black hole sources in the last decade, now seems the right moment to explore the applicability of the AEI model. Using our numerical observatory, we compute the different observables for a system with the AEI active and we take advantage of the longer timescale coming from the higher mass system, to see if the effect on the energy spectrum hinted at in LMXB, could become detectable. After confirming that the AEI causes an imprint of the QPO on the energy spectrum that should reach detectable levels in SMBH, we turned to observations of 2XMM J123103.2 and performed a proof of concept spectro-timing fit of the QPO pulse profile simultaneously with how its energy spectrum changes along it. While the limited 2XMM J123103.2 data showed the predicted effect at only $1.7\sigma$, it is fully consistent with the AEI model and hence worthy of further investigation in other systems.

We present the analysis of archival XMM-Newton observations of the symbiotic stars (SySts) HM Sge, NQ Gem, and PU Vul. The EPIC-pn spectra reveal the presence of emission lines and spectral modeling reveal unprecedented characteristics. For instance, the best fit to the EPIC-pn spectrum of the $\beta$-type SySt PU Vul reveals the presence of two plasma components. We report the discovery of an extremely soft spectral component in the EPIC-pn spectrum of the $\beta$-type Syst HM Sge which we suggest is produced by periodic mass ejections such as jets. We suggest that a simple $\beta$-type classification no longer applies to HM Sge. Finally, the spectrum of the $\beta/\delta$-type SySt NQ Gem can not be fitted by a two-temperature plasma model as performed by previous authors. The model requires extra components to fit the 1.0--4.0 keV energy range. More sophisticated models to $\beta/\delta$-type SySt are needed in order to peer into the accretion process from such systems.

Close-in giant exoplanets with temperatures greater than 2,000 K (''ultra-hot Jupiters'') have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble and Spitzer Space Telescopes. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS instrument on JWST. The data span 0.85 to 2.85 $\mu$m in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at $>$6$\sigma$ confidence) and evidence for optical opacity, possibly due to H$^-$, TiO, and VO (combined significance of 3.8$\sigma$). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy element abundance (''metallicity'', M/H = 1.03$_{-0.51}^{+1.11}$ $\times$ solar), and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the sub-stellar point that decreases steeply and symmetrically with longitude toward the terminators.

Recently, fast radio bursts (FRBs) have become a thriving field in astronomy and cosmology. Due to their extragalactic and cosmological origin, they are useful to study the cosmic expansion and the intergalactic medium (IGM). In the literature, the dispersion measure DM of FRB has been considered extensively. It could be used as an indirect proxy of the luminosity distance $d_L$ of FRB. The observed DM contains the contributions from the Milky Way (MW), the MW halo, IGM, and the host galaxy. Unfortunately, IGM and the host galaxy of FRB are poorly known to date, and hence the large uncertainties of $\rm DM_{IGM}$ and $\rm DM_{host}$ in DM plague the FRB cosmology. Could we avoid DM in studying cosmology? Could we instead consider the luminosity distance $d_L$ directly in the FRB cosmology? We are interested to find a way out for this problem in the present work. From the lessons of calibrating type Ia supernovae (SNIa) or long gamma-ray bursts (GRBs) as standard candles, we consider a universal subclassification scheme for FRBs, and there are some empirical relations for them. In the present work, we propose to calibrate type Ib FRBs as standard candles by using a tight empirical relation without DM. The calibrated type Ib FRBs at high redshifts can be used like SNIa to constrain the cosmological models. We also test the key factors affecting the calibration and the cosmological constraints.

Theoretical predictions of the population of Galactic symbiotic stars (SySts) are highly inconsistent with the current known population. Despite intense effort over the past decades, observations are still far below the predictions. The majority of known SySts so far are identified based on selection criteria established in the optical regime. The recent discovery of SU Lyn with very faint optical emission lines uncloaked a subgroup of SySts with accreting-only white dwarfs. In this particular case, the luminous red giant may overshadow the dimmed white dwarf companion. A new approach to search for this subgroup of SySts is presented, employing GALEX UV and 2MASS/AllWISE IR photometry. The FUV-NUV colour index is an indicator, direct or indirect, for the presence of hot compact companions. The cross-match of the Catalogue of Variable Stars III obtained from the All-Sky Automated Survey for SuperNovae with the GALEX, 2MASS and AllWISE catalogues result in a sample of 814 potential SySt candidates. From them, 105 sources have photometric measurements from both FUV and NUV bands and 35 exhibit FUV-NUV<1, similar to what it is expected from known SySts. Five known SySts are recovered, while two new genuine SySts are discovered in spectroscopic follow-up observations after the detection of the typical emission lines.

Axion-like particles (ALPs), which are very light neutral spin zero elusive particles primarily interacting with two photons and predicted by superstring and superbrane theories, have come to help by solving two distinct problems about blazars (a type of active galactic nuclei), thus providing two hints at the existence of ALPs themselves. In the presence of an external magnetic field, ALPs produce: (i) photon-ALP oscillations, (ii) the change of the polarization state of photons. The former effect has many consequences in the astrophysical contest, such as the modification of the transparency of the Universe and the alteration of the astrophysical spectra. We address here the latter effect by analyzing how the photon degree of linear polarization and the polarization angle get modified by photon-ALP interaction in the case where photons are generated at the jet base of some BL Lacs (a blazar class): OJ 287, BL Lacertae, Markarian 501 and 1ES 0229+200, by considering both a leptonic and hadronic emission mechanism. We show that OJ 287 and BL Lacertae are good observational targets for ALP studies both in the X-ray band with IXPE (already operative) and with the proposed eXTP, XL-Calibur, NGXP and XPP missions and in the high-energy range with the COSI, e-ASTROGAM and AMEGO missions, while 1ES 0229+200 represents a strong candidate in the X-ray band only. Since these blazars show a very high final photon degree of linear polarization, which cannot be explained by conventional physics, such a possible detection would represent an additional hint at the ALP existence. Instead, Markarian 501 does not appear as a good target for these studies. We conclude that all these observatories can give us additional fundamental information about ALP physics.

The circular polarization of gravitational waves is a powerful observable to test parity violation in gravity and to distinguish between the primordial or the astrophysical origin of the stochastic background. This property comes from the expected unpolarized nature of the homogeneous and isotropic astrophysical background, contrary to some specific cosmological sources that can produce a polarized background. However, in this work we show that there is a non-negligible amount of circular polarization also in the astrophysical background, generated by Poisson fluctuations in the number of unresolved sources, which can be detected by the third-generation interferometers with signal-to-noise ratio larger than one. We also explain in which cases the gravitational wave maps can be cleaned from this extra source of noise, exploiting the frequency and the angular dependence, in order to search for signals from the early Universe. Future studies about the detection of polarized cosmological backgrounds with ground- and space-based interferometers should account for the presence of such a foreground contribution.

We conducted a TEM study of an unusual oxide-silicate composite presolar grain (F2-8) from the unequilibrated ordinary chondrite Semarkona. The presolar composite grain is relatively large, has an amoeboidal shape, and contains Mg-rich olivine, Mg-Al spinel, and Ca-rich pyroxene. The shape and phase assemblage are reminiscent of amoeboid-olivine-aggregates and add to the growing number of TEM observations of presolar refractory inclusion-like (CAIs and AOAs) grains. In addition to the dominant components, F2-8 also contains multiple subgrains, including an alabandite-oldhamite composite grain within the olivine and several magnetite subgrains within the Mg-Al spinel. We argue that the olivine, Mg-Al spinel, and alabandite-oldhamite formed by equilibrium condensation, whereas the Ca-rich pyroxene formed by non-equilibrium condensation, all in an M-type AGB star envelope. On the other hand, the magnetite subgrains are likely the result of aqueous alteration on the Semarkona asteroidal parent body. Additional evidence of secondary processing includes Fe-enrichment in the Mg-Al spinel and olivine, elevated Al contents in the olivine, and beam sensitivity and a modulated structure for the olivine. Compound presolar grains record condensation conditions over a wide range of temperatures. Additionally, the presence of several different presolar phases in a composite grain can impart information on the relative rates and effects of post-condensation processing in a range of environments, including the interstellar medium, solar nebula, and the host asteroid parent body. The TEM observations of F2-8 provide insights across the lifetime of the grain from its formation by condensation in an M-type AGB star envelope, its transit through the interstellar medium, and aqueous alteration during its residence on Semarkona's asteroidal parent body.

The Lyman-Werner (LW) radiation field is a key ingredient in the chemo-thermal evolution of gas in the Early Universe, as it dissociates H2 molecules, the primary cooling channel in an environment devoid of metals and dust. Despite its important role, it is still not implemented in cosmological simulations on a regular basis, in contrast to the general UV background. This is in part due to uncertainty in the source modelling, their spectra and abundance, as well as the detailed physics involved in the propagation of the photons and their interactions with the molecules. To overcome these difficulties, we present here a model (with the relative fit) for the mean LW intensity during the first billion years after the Big Bang, obtained by post-processing the high-resolution FiBY simulations with an approximated radiative transfer method that employs accurate cross sections for H2, as well as for H- and H2+, the chemical species associated with its formation. Absorption by neutral Hydrogen in the IGM and various spectral models for Population III and Population II stars are also included. Our model can be easily applied to other simulations or semi-analytical models as an external homogeneous source of radiation that regulates the star formation in low-mass halos at high-z. We also show how to account for spatial inhomogeneities in the LW radiation field, originating from massive star-forming galaxies that dominate the photon budget up to distances of $\sim100$ proper kpc. Such inhomogeneities have a strong impact on the H2 abundance and the feasibility of scenarios such as the formation of Direct Collapse Black Holes (DCBHs).

Various experiments and observations have led researchers to suggest different bounds on fundamental constants like the fine-structure constant and the proton-to-electron mass ratio. These bounds differ mostly due to the energy scale of the systems where the experiments are performed. In this article, we obtain bounds on these parameters in the modified gravity context using the Gaia-DR2 massive white dwarf data and show that the bounds alter as the gravity theory changes. This exploration not only indicates strong support for non-negligible influences of modified gravity in astrophysical scenarios in high-density regimes but also reveals that the bounds on fundamental parameters can be much stronger under alternate gravity theories.

We argue for a relation between the supersymmetry breaking scale and the measured value of the dark energy density $\Lambda$. We derive it by combining two quantum gravity consistency swampland constraints, which tie the dark energy density $\Lambda$ and the gravitino mass $M_{3/2}$, respectively, to the mass scale of a light Kaluza-Klein tower and, therefore, to the UV cut-off of the effective theory. Whereas the constraint on $\Lambda$ has recently led to the Dark Dimension scenario, with a prediction of a single mesoscopic extra dimension of the micron size, we use the constraint on $M_{3/2}$ to infer the implications of such a scenario for the scale of supersymmetry breaking. We find that a natural scale for supersymmetry signatures is $M={\cal O}\left(\Lambda^{1/8}\right)={\cal O}({\rm TeV})$. This mass scale is within reach of LHC and of the next generation of hadron colliders. Finally, we discuss possible string theory and effective supergravity realizations of the Dark Dimension scenario with broken supersymmetry.

If dark matter interacts too strongly with nuclei, it could be slowed to undetectable speeds in Earth's crust or atmosphere before ever reaching a detector. For sub-GeV dark matter, analytic approximations appropriate for heavier dark matter fail, necessitating the use of computationally expensive simulations. We present a new method of modeling attenuation of light dark matter in the Earth, based on the approximation that the scattering is isotropic in the lab frame. We show that this approach agrees well with Monte Carlo results, and can be much faster when the number of scatterings becomes large, as the runtime for Monte Carlo methods increases exponentially with cross section. We use this method to model attenuation for sub-dominant dark matter--that is, particles that make up a small fraction of the dark matter density--and show that previous work on sub-dominant dark matter overestimates the sensitivity of direct detection experiments.

In Maples et al. (2018) we introduced Robust Chauvenet Outlier Rejection, or RCR, a novel outlier rejection technique that evolves Chauvenet's Criterion by sequentially applying different measures of central tendency and empirically determining the rejective sigma value. RCR is especially powerful for cleaning heavily-contaminated samples, and unlike other methods such as sigma clipping, it manages to be both accurate and precise when characterizing the underlying uncontaminated distributions of data sets, by using decreasingly robust but increasingly precise statistics in sequence. For this work, we present RCR from a software standpoint, newly implemented as a Python package while maintaining the speed of the C++ original. RCR has been well-tested, calibrated and simulated, and it can be used for both one-dimensional outlier rejection and $n$-dimensional model-fitting, with or without weighted data. RCR is free to use for academic and non-commercial purposes, and the code, documentation and accompanying web calculator can be found and easily used online at https://github.com/nickk124/RCR

Based on the Skyrme-Hartree-Fock model (SHF) as well as its extension (the Korea-IBS-Daegu-SKKU (KIDS) model) and the relativistic mean-field (RMF) model, we have studied the constraints on the parameters of the nuclear matter equation of state (EOS) from adopted astrophysical observables using a Bayesian approach. While the masses and radii of neutron stars generally favors a stiff isoscalar EOS and a relatively soft nuclear symmetry energy, model dependence on the constraints is observed and mostly originates from the incorporation of higher-order EOS parameters and difference between relativistic and non-relativistic models. At twice saturation density, the value of the symmetry energy is constrained to be $48^{+15}_{-11}$ MeV in the standard SHF model, $48^{+8}_{-15}$ MeV in the KIDS model, and $48^{+5}_{-6}$ MeV in the RMF model, around their maximum {\it a posteriori} values within $68\%$ confidence intervals. Our study helps to obtain a robust constraint on nuclear matter EOS, and meanwhile, to understand the model dependence of the results.

We study the effects of a massive field with a continuous spectrum (continuum isocurvaton) on the inflationary bispectrum in the squeezed limit. As a concrete example, we extend the quasi-single field inflation model to include a continuum isocurvaton with a well-motivated spectral density from extra dimensions and focus on a contribution to the bispectrum with a single continuum isocurvaton exchange. In contrast to the usual case without the continuous spectrum, the amplitude of the bispectrum has a damping feature in the deep squeezed limit, which can be strong evidence for the continuous spectrum.

The observed alignment of spots in the x-ray films in cosmic ray emulsion experiments is analyzed and interpreted in the framework of geometrical approach. It is shown that the high degree of alignment can appear partly due to the selection procedure of most energetic particles itself and the threshold on the energy deposition together with the transverse momentum conservation.

For any given network of detectors, and for any given integration time, even in the idealized limit of negligible instrumental noise, the intrinsic time variation of the isotropic component of the Stochastic Gravitational Wave Background (SGWB) induces a limit on how accurately the anisotropies in the SGWB can be measured. We show here how this sample limit can be calculated and apply this to three separate configurations of ground-based detectors placed at existing and planned sites. Our results show that in the idealized, best-case scenario individual multipoles of the anisotropies at $\ell \leq 8$ can only be measured to $\sim 10^{-5} - 10^{-4}$ level over 5 years of observation as a fraction of the isotropic component. As the sensitivity improves as the square root of the observation time, this poses a very serious challenge for the measurement of the anisotropies of SGWB of cosmological origin, even in the case of idealised detectors with arbitrarily low instrumental noise.

In this work we examine the Swampland criteria for a specific class of rescaled $f(R)$ gravitational models, that are capable of unifying the primordial era of the Universe with the late-time era with the inclusion of string corrections. In particular, we develop separately the theoretical framework of Gauss-Bonnet and Chern-Simons theories considering that, the rescale parameter is constrained to reside in the area $0<\alpha<1$. As showcased, in the context of the aforementioned theories, a viable inflationary phenomenology consistent with the latest Planck data can be obtained for both cases for a wide variety of values. The Swampland criteria which where examined are satisfied, not necessarily simultaneously, for small values of the rescale parameter, which is in agreement with the case of a canonical scalar field with absent string corrective terms. The Gauss-Bonnet model is also further constrained, in order to obtain a propagation velocity of tensor perturbations which coincides with that of light, according to the recent observations from the GW170817. As a result of this assumption the degrees of freedom of the theory are reduced. An interesting feature which arises from the overall phenomenology is that, due to the inclusion of string corrections the tensor spectral index of primordial perturbations is now capable of obtaining a positive value which is not possible in the case of the canonical scalar field. Last but not least, the power-law model which is known to be incompatible with observations is now rendered viable by including a parity violating term and as showcased, it satisfies the Swampland criteria as well.

We introduce an action-angle formalism for bounded geodesic motion in Kerr black hole spacetime using canonical perturbation theory. Namely, we employ a Lie series technique to produce a series of canonical transformations on a Hamiltonian function describing geodesic motion in Kerr background written in Boyer-Lindquist coordinates to a Hamiltonian system written in action-angle variables. This technique allows us to produce a closed-form invertible relation between the Boyer-Lindquist variables and the action-angle ones, while it generates in analytical closed form all the characteristic functions of the system as well. The expressed in the action-angle variable Hamiltonian system is employed to model an extreme mass ratio inspiral (EMRI), i.e. a binary system where a stellar compact object inspirals into a supermassive black hole due to gravitational radiation reaction. We consider the adiabatic evolution of an EMRI, for which the energy and angular momentum fluxes are computed by solving the Teukolsky equation in the frequency domain. To achieve this a new Teukolsky equation solver code was developed.

The high density behavior of nuclear matter is analyzed within a relativistic mean field description with non-linear meson interactions. To assess the model parameters and their output, a Bayesian inference technique is used. The Bayesian setup is limited only by a few nuclear saturation properties, the neutron star maximum mass larger than 2 M$_\odot$, and the low-density pure neutron matter equation of state (EOS) produced by an accurate N$^3$LO calculation in chiral effective field theory. Depending on the strength of the non-linear scalar vector field contribution, we have found three distinct classes of EOSs, each one correlated to different star properties distributions. If the non-linear vector field contribution is absent, the gravitational maximum mass and the sound velocity at high densities are the greatest. However, it also gives the smallest speed of sound at densities below three times saturation density. On the other hand, models with the strongest non-linear vector field contribution, predict the largest radii and tidal deformabilities for 1.4 M$_\odot$ stars, together with the smallest mass for the onset of the nucleonic direct Urca processes and the smallest central baryonic densities for the maximum mass configuration. These models have the largest speed of sound below three times saturation density, but the smallest at high densities, in particular, above four times saturation density the speed of sound decreases approaching approximately $\sqrt{0.4}c$ at the center of the maximum mass star. On the contrary, a weak non-linear vector contribution gives a monotonically increasing speed of sound. A 2.75 M$_\odot$ NS maximum mass was obtained in the tail of the posterior with a weak non-linear vector field interaction. This indicates that the secondary object in GW190814 could also be an NS.

We propose to use table-top-size ultra-stable optical cavities from the state-of-the-art optical atomic clocks as bar gravitational wave detectors for the frequencies higher than 2 kHz. We show that 2-20 kHz range of gravitational waves' spectrum can be accessed with instruments below 2 meters in size. The proposed cavities' materials and properties are being within the present-day technology grasp. The ultra-stable optical cavities allow detecting not only predicted gravitational wave signals from such sources as binary neutron star mergers and post-mergers, subsolar-mass primordial black-hole mergers, and collapsing stellar cores, but can reach new physics beyond standard model looking for ultralight bosons such as QCD axions and axion-like particles formed through black hole superradiance.