Papers for Friday, Oct 13 2023

In order for telescopes to obtain good and precise images they need to see through atmospheric turbulence. To accomplish this and compensate for atmospheric turbulence we use Adaptive Optics technologies. In this thesis we analyze the variations in phase delays across phase plates which simulate atmospheric turbulence in order to characterize them and determine how well these phase plates reproduce the phase delay variation of the atmosphere. This experiment was conducted using the Quadrature Polarization Interferometer (QPI) testbed in the Lab of Adaptive Optics (LAO) at the University of California Santa Cruz (UCSC). Using the QPI lab setup allowed us to be able to develop and refine a final algorithm for determining the phase delay of the phase plates. The characterization of the phase plates was accomplished by using the interference patterns between a test and reference path and measuring their pathlength variations. This was achieved by calculating the intensity of the two paths of the Helium-Neon (HeNe) laser, modifying those values in order to obtain phase values between the beam, and from the phase values we are able to determine the path length variations, or phase delays, of the phase plates. This allows us to determine Fried's parameter, $r_o$, by analyzing any given separation on the phase plate and determining the path length variations between those separations.

The classification of galaxy morphologies is an important step in the investigation of theories of hierarchical structure formation. While human expert visual classification remains quite effective and accurate, it cannot keep up with the massive influx of data from emerging sky surveys. A variety of approaches have been proposed to classify large numbers of galaxies; these approaches include crowdsourced visual classification, and automated and computational methods, such as machine learning methods based on designed morphology statistics and deep learning. In this work, we develop two novel galaxy morphology statistics, descent average and descent variance, which can be efficiently extracted from telescope galaxy images. We further propose simplified versions of the existing image statistics concentration, asymmetry, and clumpiness, which have been widely used in the literature of galaxy morphologies. We utilize the galaxy image data from the Sloan Digital Sky Survey to demonstrate the effective performance of our proposed image statistics at accurately detecting spiral and elliptical galaxies when used as features of a random forest classifier.

The Mapper of the IGM Spin Temperature (MIST) is a new ground-based, single-antenna, radio experiment attempting to detect the global 21 cm signal from the Dark Ages and Cosmic Dawn. A significant challenge in this measurement is the frequency-dependence, or chromaticity, of the antenna beam directivity. MIST observes with the antenna above the soil and without a metal ground plane, and the beam directivity is sensitive to the electrical characteristics of the soil. In this paper, we use simulated observations with MIST to study how the detection of the global 21 cm signal from Cosmic Dawn is affected by the soil and the MIST beam directivity. We simulate observations using electromagnetic models of the directivity computed for single- and two-layer models of the soil. We test the recovery of the Cosmic Dawn signal with and without beam chromaticity correction applied to the simulated data. We find that our single-layer soil models enable a straightforward recovery of the signal even without chromaticity correction. Two-layer models increase the beam chromaticity and make the recovery more challenging. However, for the model in which the bottom soil layer has a lower electrical conductivity than the top layer, the signal can be recovered even without chromaticity correction. For the other two-layer models, chromaticity correction is necessary for the recovery of the signal and the accuracy requirements for the soil parameters vary between models. These results will be used as a guideline to select observation sites that are favorable for the detection of the Cosmic Dawn signal.

Dark matter self-interactions may have the capability to solve or at least mitigate small-scale problems of the cosmological standard model, {\Lambda}CDM. There are a variety of self-interacting dark matter (SIDM) models that lead to distinguishable astrophysical predictions and hence varying success in explaining observations. Studies of dark matter (DM) density cores on various mass scales suggest a velocity-dependent scattering cross-section. In this work we investigate how a velocity dependence alters the evolution of the DM distribution for frequent DM scatterings and compare to the velocity-independent case. We demonstrate that these cases are qualitatively different using a test problem. Moreover, we study the evolution of the density profile of idealised DM haloes and find that a velocity dependence can lead to larger core sizes and different time scales of core formation and core collapse. In cosmological simulations, we investigate the effect of velocity-dependent self-interaction on haloes and satellites in the mass range of $\approx 10^{11} - 10^{14}$ M$_\odot$. We study the abundance of satellites, density and shape profiles and try to infer qualitative differences between velocity-dependent and velocity-independent scatterings as well as between frequent and rare self-interactions. We find that a strongly velocity-dependent cross-section can significantly amplify the diversity of rotation curves, independent of the angular dependence of the differential cross-section. We further find that the abundance of satellites in general depends on both the velocity dependence and the scattering angle, although the latter is less important for strongly velocity-dependent cross-sections.

To reduce systematic uncertainties in Type Ia supernova (SN Ia) cosmology, the host galaxy dust law shape parameter, $R_V$, must be accurately constrained. We thus develop a computationally-inexpensive pipeline, Bird-Snack, to rapidly infer dust population distributions from optical-near infrared SN colours at peak brightness, and determine which analysis choices significantly impact the population mean $R_V$ inference, $\mu_{R_V}$. Our pipeline uses a 2D Gaussian process to measure peak $BVriJH$ apparent magnitudes from SN light curves, and a hierarchical Bayesian model to simultaneously constrain population distributions of intrinsic and dust components. Fitting a low-to-moderate-reddening sample of 65 low-redshift SNe yields $\mu_{R_V}=2.61^{+0.38}_{-0.35}$, with $68\%(95\%)$ posterior upper bounds on the population dispersion, $\sigma_{R_V}<0.92(1.96)$. This result is robust to various analysis choices, including: the model for intrinsic colour variations, fitting the shape hyperparameter of a gamma dust extinction distribution, and cutting the sample based on the availability of data near peak. However, these choices may be important if statistical uncertainties are reduced. With larger near-future optical and near-infrared SN samples, Bird-Snack can be used to better constrain dust distributions, and investigate potential correlations with host galaxy properties. Bird-Snack is publicly available; the modular infrastructure facilitates rapid exploration of custom analysis choices, and quick fits to simulated datasets, for better interpretation of real-data inferences.

We illuminate the altered evolution of galaxies in clusters compared to the field by tracking galaxies in the IllustrisTNG300 simulation as they enter isolated clusters of mass $10^{13} < M_{\rm 200, mean} / {\rm M}_\odot < 10^{15}$ (at $z=0$). We demonstrate significant trends in galaxy properties with residence time (time since first infall) and that there is a population of galaxies that remain star-forming even many Gyrs after their infall. By comparing the properties of galaxies at their infall time to their properties at $z=0$, we show how scaling relations, like the stellar-to-halo mass ratio, shift as galaxies live in the cluster environment. Galaxies with a residence time of 10 Gyr increase their stellar-to-halo mass ratio, by around 1 dex. As measurements of the steepest slope of the galaxy cluster number density profile ($R_{\rm st}$), frequently used as a proxy for the splashback radius, have been shown to depend strongly on galaxy selection, we show how $R_{\rm st}$ depends on galaxy residence time. Using galaxies with residence times less than one cluster crossing time ($\approx 5$ Gyr) to measure $R_{\rm st}$ leads to significant offsets relative to using the entire galaxy population. Galaxies must have had the opportunity to `splash back' to the first caustic to trace out a representative value of $R_{\rm st}$, potentially leading to issues for galaxy surveys using UV-selected galaxies. Our wok demonstrates that the evolution of cluster galaxies continues well into their lifetime in the cluster and departs from a typical field galaxy evolutionary path.

While space-borne optical and near-infrared facilities have succeeded in delivering a precise and spatially resolved picture of our Universe, their small survey area is known to under-represent the true diversity of galaxy populations. Ground-based surveys have reached comparable depths but at lower spatial resolution, resulting in source confusion that hampers accurate photometry extractions. What once was limited to the infrared regime has now begun to challenge ground-based ultra-deep surveys, affecting detection and photometry alike. Failing to address these challenges will mean forfeiting a representative view into the distant Universe. We introduce The Farmer: an automated, reproducible profile-fitting photometry package that pairs a library of smooth parametric models from The Tractor (Lang et al. 2016) with a decision tree that determines the best-fit model in concert with neighboring sources. Photometry is measured by fitting the models on other bands leaving brightness free to vary. The resulting photometric measurements are naturally total, and no aperture corrections are required. Supporting diagnostics (e.g. $\chi^2$) enable measurement validation. As fitting models is relatively time intensive, The Farmer is built with high-performance computing routines. We benchmark The Farmer on a set of realistic COSMOS-like images and find accurate photometry, number counts, and galaxy shapes. The Farmer is already being utilized to produce catalogs for several large-area deep extragalactic surveys where it has been shown to tackle some of the most challenging optical and near-infrared data available, with the promise of extending to other ultra-deep surveys expected in the near future. The Farmer is available to download from GitHub and Zenodo.

Circumbinary accretion occurs throughout the universe, from the formation of stars and planets to the aftermath of major galactic mergers. We present an extensive investigation of circumbinary accretion disks, studying circular binaries with mass ratios ($q\equiv M_2/M_1$) from 0.01 to 1 and at each mass ratio probing the effects of disk thickness and viscosity. We study disks with aspect ratios $H/r\in\{0.1, 0.05, 0.033\}$, and vary both the magnitude and spatial dependance of viscosity. Although thin accretion disks have previously been found to promote rapid inspirals of equal-mass binaries, we find that gravitational torques become weaker at lower mass ratios and most binaries with $0.01\leq q\leq0.04$ outspiral, which may delay the coalescence of black hole binaries formed from minor mergers and cause high-mass exoplanets to migrate outwards. However, in a number of cases, the disks accreting onto binaries with mass ratios $\sim 0.07$ fail to develop eccentric modes, leading to extremely rapid inspirals. Variability in black hole accretion correlates with disk eccentricity, and we observe variability above the $\sim10\%$ level even for mass ratios of $0.01$. We demonstrate that the spatial dependence of the viscosity (e.g. $\alpha$ vs constant-$\nu$) significantly affects the degree of preferential accretion onto the secondary, resolving discrepancies between previous studies. Colder circumbinary disks remain eccentric even at $q\sim0.01$ and sustain deep, asymmetric cavities.

The study of the morphology of 2D projected maps of galaxy clusters is a suitable approach to infer, from real data, the dynamical state of those systems. We recently developed a new method to recover the morphological features in galaxy cluster maps which consists of an analytical modelling through the Zernike polynomials. After the first validation of this approach on a set of high-resolution mock maps of the Compton parameter, $y$, from hydrodynamically simulated galaxy clusters in THE THREE HUNDRED project, we apply the Zernike modelling on $y$-maps of local ($z < 0.1$) galaxy clusters observed by the $Planck$ satellite. With a single parameter collecting the main information of the Zernike modelling, we classify their morphology. A set of mock $Planck$-like $y$-maps, generated from THE THREE HUNDRED clusters, is also used to validate our indicator with a proper dynamical state classification. This approach allows us to test the efficiency of the Zernike morphological modelling in evaluating the dynamical population in the real $Planck$ sample.

Sagittarius A* (SgrA*) exhibits frequent flaring activity across the electromagnetic spectrum. Signatures of an orbiting hot spot have been identified in the polarized millimeter wavelength light curves observed with ALMA in 2017 immediately after an X-ray flare. The nature of these hot spots remains uncertain. We expanded existing theoretical hot spot models created to describe the Sgr~A* polarized emission at millimeter wavelengths. We sample the posterior space, identifying best-fitting parameters and characterizing uncertainties. Using the numerical radiative transfer code IPOLE we defined a semi-analytical model describing a ball of plasma orbiting Sgr~A*, threaded with a magnetic field and emitting synchrotron radiation. We then explore the posterior space in the Bayesian framework of DYNESTY. We fitted the static background emission separately, using a radiatively inefficient accretion flow model. We considered eight models with a varying level of complexity. All models converge to realisations that fit the data, but two models, one with cooling and one with non-Keplerian motion, improve the fit significantly, while additionally matching the expected synchrotron cooling timescale and observed circular polarization. Our models represent observational data well, and allow for testing of the impact of various effects in a systematic manner. From our analysis we have inferred an inclination of $\sim150-160$ deg, corroborating previous estimates, a preferred period of $\sim$ $90$ minutes and an orbital radius of $10.7 - 13.0$ gravitational radii. Our non-Keplerian models indicate a preference for an orbital velocity of $0.8-0.9$ times the Keplerian value. Lastly, our best models agree on a low dimensionless spin value ($a_* < 0.6$), however, the impact of spin on the corresponding light curves is subdominant with respect to other parameters.

We introduce the SDSS/APOGEE Value Added Catalogue of Galactic Globular Cluster (GC) Stars. The catalogue is the result of a critical search of the APOGEE data release 17 (DR17) catalogue for candidate members of all known Galactic GCs. Candidate members are assigned to various GCs on the basis of position on the sky, proper motion, and radial velocity. The catalogue contains a total of 7,737 entries for 6,422 unique stars associated with 72 Galactic GCs. Full APOGEE DR17 information is provided, including radial velocities and abundances for up to 20 elements. Membership probabilities estimated on the basis of precision radial velocities are made available. Comparisons with chemical compositions derived by the GALAH survey, as well as optical values from the literature, show good agreement. This catalogue represents a significant increase in the public database of GC star chemical compositions and kinematics, providing a massive homogeneous data set that will enable a variety of studies. The catalogue in fits format is available for public download from the SDSS-IV DR17 value added catalogue website.

We test the relationship between UV-derived star formation rates (SFRs) and the 7.7 ${\mu}$m polycyclic aromatic hydrocarbon (PAH) luminosities from the integrated emission of galaxies at z ~ 0 - 2. We utilize multi-band photometry covering 0.2 - 160 ${\mu}$m from HST, CFHT, JWST, Spitzer, and Herschel for galaxies in the Cosmic Evolution Early Release Science (CEERS) Survey. We perform spectral energy distribution (SED) modeling of these data to measure dust-corrected far-UV (FUV) luminosities, $L_{FUV}$, and UV-derived SFRs. We then fit SED models to the JWST/MIRI 7.7 - 21 ${\mu}$m CEERS data to derive rest-frame 7.7 ${\mu}$m luminosities, $L_{770}$, using the average flux density in the rest-frame MIRI F770W bandpass. We observe a correlation between $L_{770}$ and $L_{FUV}$, where log $L_{770}$ is proportional to (1.27+/-0.04) log $L_{FUV}$. $L_{770}$ diverges from this relation for galaxies at lower metallicities, lower dust obscuration, and for galaxies dominated by evolved stellar populations. We derive a "single-wavelength" SFR calibration for $L_{770}$ which has a scatter from model estimated SFRs (${{\sigma}_{{\Delta}SFR}}$) of 0.24 dex. We derive a "multi-wavelength" calibration for the linear combination of the observed FUV luminosity (uncorrected for dust) and the rest-frame 7.7 ${\mu}$m luminosity, which has a scatter of ${{\sigma}_{{\Delta}SFR}}$ = 0.21 dex. The relatively small decrease in ${\sigma}$ suggests this is near the systematic accuracy of the total SFRs using either calibration. These results demonstrate that the rest-frame 7.7 ${\mu}$m emission constrained by JWST/MIRI is a tracer of the SFR for distant galaxies to this accuracy, provided the galaxies are dominated by star-formation with moderate-to-high levels of attenuation and metallicity.

Confronting measurements of the Lyman-$\alpha$ forest with cosmological hydrodynamical simulations has produced stringent constraints on models of particle dark matter and the thermal and ionization state of the intergalactic medium. We investigate the robustness of such models of the Lyman-$\alpha$ forest, focussing on the effect of particle initial conditions on the Lyman-$\alpha$ forest statistics in cosmological SPH simulations. We study multiple particle initialization algorithms in simulations that are designed to be identical in other respects. In agreement with the literature, we find that the correct linear theory evolution is obtained when a glass-like configuration is used for initial unperturbed gas particle positions alongside a regular grid configuration for dark matter particles and the use of non-identical initial density perturbations for gas and dark matter. However, we report that this introduces a large scale-dependent distortion in the one-dimensional Lyman-$\alpha$ transmission power spectrum at small scales ($k > 0.05$s/km). The effect is close to $50\%$ at $k\sim 0.1$s/km, and persists at higher resolution. This can severely bias inferences in parameters such as the dark matter particle mass. By considering multiple initial conditions codes and their variations, we also study the impact of a variety of other assumptions and algorithmic choices, such as adaptive softening, background radiation density, particle staggering, and perturbation theory accuracy, on the matter power spectrum, the Lyman-$\alpha$ flux power spectrum, and the Lyman-$\alpha$ flux PDF. This work reveals possible pathways towards more accurate theoretical models of the Lyman-$\alpha$ forest to match the quality of upcoming measurements.

Self-interacting dark matter (SIDM) has been proposed to solve small-scale problems in $\Lambda$CDM cosmology. In previous work, constraints on the self-interaction cross-section of dark matter have been derived assuming that the self-interaction cross-section is independent of velocity. However, a velocity-dependent cross-section is more natural in most theories of SIDM. Using idealized $N$-body simulations, we study merging clusters, with velocity-dependent SIDM. In addition to the usual rare scattering in the isotropic limit, we also simulate these systems with anisotropic, small-angle (frequent) scatterings. We study the qualitative features of the mergers and we find that the effects of velocity-dependent cross-sections are observed when comparing early-time and late-time oscillation amplitude of the brightest cluster galaxy (BCG). Finally, we also extend the existing upper bounds on the velocity-independent, isotropic self-interaction cross-section to the parameter space of rare and frequent velocity-dependent self-interactions by studying the central densities of dark matter only isolated haloes. For these upper-bound parameters, we find that the offsets just after the first pericentre to be $\leq$ 10 kpc. On the other hand, because of BCG oscillations, we speculate that the distribution of BCG offsets in relaxed cluster to be a statistically viable probe. Therefore, this motivates further studies of BCG off-centering in cosmological simulations.

In this work, we analysed new LOw Frequency ARray observations of the mini halo in the cluster RBS797, together with archival Very Large Array observations and the recent Chandra results. This cluster is known to host a powerful active galactic nucleus (AGN) at its centre, with two pairs of jets propagating in orthogonal directions. Recent X-ray observations have detected three pairs of shock fronts, connected with the activity of the central AGN. Our aim is to investigate the connection between the mini halo emission and the activity of the central source. We find that the diffuse radio emission is elongated in different directions at 144 MHz (east-west) with respect to 1.4 GHz (north-south), tracing the orientation of the two pairs of jets. The mini halo emission is characterised by an average spectral index $\alpha=-1.02\pm 0.05$. The spectral index profile of the mini halo shows a gradual flattening from the centre to the periphery. Such a trend is unique among the mini halos studied to date, and resembles the spectral index trend typical of particles re-accelerated by shocks. However, the estimated contribution to the radio brightness profile coming from shock re-acceleration is found to be insufficient to account for the radial brightness profile of the mini halo. We propose three scenarios that could explain the observed trend: (i) the AGN-driven shocks are propagating onto an already existing mini halo, re-energising the electrons. We estimate that the polarisation induced by the shocks could be detected at 6 GHz and above; (ii) we could be witnessing turbulent re-acceleration in a high magnetic field cluster; and (iii) the mini halo could have a hadronic origin, in which the particles are injected by Future observations in polarisation would be fundamental to understand the role of shocks and the magnetic field.

Neutron stars and stellar-mass black holes are the remnants of massive star explosions. Most massive stars reside in close binary systems, and the interplay between the companion star and the newly formed compact object has been theoretically explored, but signatures for binarity or evidence for the formation of a compact object during a supernova explosion are still lacking. Here we report a stripped-envelope supernova, SN 2022jli, which shows 12.4-day periodic undulations during the declining light curve. Narrow H$\alpha$ emission is detected in late-time spectra with concordant periodic velocity shifts, likely arising from hydrogen gas stripped from a companion and accreted onto the compact remnant. A new Fermi/LAT $\gamma$-ray source is temporally and positionally consistent with SN 2022jli. The observed properties of SN 2022jli, including periodic undulations in the optical light curve, coherent H$\alpha$ emission shifting, and evidence for association with a $\gamma$-ray source, point to the explosion of a massive star in a binary system leaving behind a bound compact remnant. Mass accretion from the companion star onto the compact object powers the light curve of the supernova and generates the $\gamma$-ray emission.

The Extreme Universe Space Observatory on a Super Pressure Balloon II (EUSO-SPB2) measured extensive air showers (EASs) from upward-going High Energy Cosmic Rays by flying a Cherenkov Telescope (CT) at 33 km altitude. The telescope could be tilted just above the Earth's limb, 5.8 degrees below horizontal, and 650 km away as viewed from the balloon. This configuration enables the detection of EASs that develop over a longer path length than downward-going showers. The lifetime of 100 GeV muons, as an example, corresponds to a path length of 620 km in Earth's upper atmosphere, where there is a decreased amount of energy lost due to atmospheric interactions (only approximately 40 MeV/km lost at 15 km altitude). In this configuration, muons can travel hundreds of kilometers while bending in Earth's geomagnetic field before they decay. These effects cause EASs to be more dense with muons at larger shower depths compared to the shower at Xmax, a result known as the muon tail. The objective of this simulation is to understand whether the CT on EUSO-SPB2 could measure the Cherenkov signal produced by the muon tail and observe the effects of the muons deflecting in Earth's geomagnetic field. We found that the timing and angular distributions of the Cherenkov signal allow the muon component to be separated from the main Cherenkov signal and we identified quantifiable effects of the muons deflecting in the geomagnetic field. However, at this time we are unable to simulate enough events to analyze the distribution of photons arriving in an area the size of the aperture of the CT. Thus, we cannot make conclusions about whether these effects can be seen by EUSO-SPB2.

High resolution spectra with iSHELL on IRTF in the K and M band of the young, heavily accreting B 1.5e star MWC297 show numerous double-peaked CO lines. These CO lines originate in an inclined gaseous disk in Keplerian rotation. MWC297 is the only early B star known to show a Keplerian disk in CO. Analysis of the spectra show that 12CO 1 - 0 is optically thick for the low excitation lines. Even the 13CO 1 - 0 and 12CO 2 - 1 have somewhat optically thick lines at low J levels. We find that the CO emission in the disk can be fitted with CO being in a narrow ring at a radius of 12 AU, with a temperature of 1500 K, and a CO column density of 1.6 e18 cm-2. This model underestimates the line strength of high J lines, indicating that they are excited by fluorescence. The CO overtone lines have a similar temperature, The 13CO lines are much brighter than expected from interstellar isotope ratios. The 13CO lines are wider than the 12CO ones suggesting different excitation conditions. The same is true for 12CO 2 - 1. We see strong absorption in 12CO and 13CO 1 - 0 at low J levels, which is due to two two cold foreground clouds. These clouds, one with a temperature of 8.3 K and a column density of 6.7 e17 cm-2, and the other one colder and with lower column density, can fully account for the observed extinction toward MWC297.

In his 2021 lecture to the Canadian Association of Physicists Congress, P.J.E. Peebles pointed out that the brightest extra-galactic radio sources tend to be aligned with the plane of the de Vaucouleur Local Supercluster up to redshifts of $z=0.02$ ($d_{\rm MW}\approx 85~\rm{Mpc}$). He then asked whether such an alignment of clusters is anomalous in the standard $\Lambda$CDM framework. In this letter, we define an alternative, absolute orientation agnostic, measure of the anisotropy of these brightest sources and use a large cosmological simulation to measure how common such an alignment of structures is. We find that only 3.5% of randomly selected regions display an anisotropy of their clusters more extreme than the one found in the local Universe's radio data. This sets the region around the Milky Way as a $1.85\sigma$ outlier. Varying the selection parameters of the objects in the catalogue, we find that the clusters in the local volume are never more than $2\sigma$ away from the simulations' prediction for the same selection. We thus conclude that the reported anisotropy, whilst note-worthy, is not in tension with the $\Lambda$CDM paradigm.

We report the serendipitous discovery of a very metal-poor (VMP) Li-rich giant star ($T_{\rm eff}$ = 4690$\pm$80 K, log g = 1.34$\pm$0.13, [Fe/H] = $-2.43\pm$0.07). We analyse the Li I 6103 and 6707 \r{A} lines accounting for departures from local thermodynamic equilibrium (NLTE) and correcting for 3D effects using literature data, which yields a lithium abundance $\log\varepsilon_{Li} = 3.42\pm0.07$. Comparing lithium abundances from the two lines, in 1D NLTE we measure the isotope ratio $^6$Li/$^7$Li = 1.64$^{+1.49}_{-1.08}$ %. When correcting for 3D effects, we detect the fragile $^6$Li isotope at $2$-sigma level and the ratio $^6$Li/$^7$Li = 5.65$^{+5.05}_{-2.51}$ %. To our knowledge, this is the first $^6$Li/$^7$Li measurement in an extremely Li-rich VMP star. The Cameron-Fowler mechanism, which is proposed to produce Li-rich stars, does not imply $^6$Li production and is therefore inconsistent with our measurement when applying 3D corrections. We also derive NLTE abundances for 16 elements, most of which show similar abundances to those found in VMP stars. Sodium is an exception: [Na/Fe]$_{\rm NLTE, 1D}$ = 0.07 $\pm 0.03$, which is 0.5 dex higher than what is typical for VMP stars. This star joins the sample of rare Li-rich VMP stars, and we offer a novel way to constrain the source of lithium in such stars through isotope ratio measurements.

This study focuses on modelling galaxy cluster gas profiles via a semi-parametric nodal approach. While traditional methods like the generalised Navarro-Frenk-White (gNFW) often encounter parameter degeneracy, our flexible node-based method precisely defines a cluster gas pressure profile. Using Planck space telescope data from the Coma region, our model, focused on the pressure-radius relationship, showcases enhanced flexibility over the gNFW. Bayesian analyses indicated an optimal five-node structure for the Coma cluster pressure profile.

The increasing statistical precision of photometric redshift surveys requires improved accuracy of theoretical predictions for large-scale structure observables to obtain unbiased cosmological constraints. In $\Lambda$CDM cosmologies, massive neutrinos stream freely at small cosmological scales, suppressing the small-scale power spectrum. In massive neutrino cosmologies, galaxy bias modeling needs to accurately relate the scale-dependent growth of the underlying matter field to observed galaxy clustering statistics. In this work, we implement a computationally efficient approximation of the neutrino-induced scale-dependent bias (NISDB). Through simulated likelihood analyses of Dark Energy Survey Year 3 (DESY3) and Legacy Survey of Space and Time Year 1 (LSSTY1) synthetic data that contain an appreciable NISDB, we examine the impact of linear galaxy bias and neutrino mass modeling choices on cosmological parameter inference. We find model misspecification of the NISDB approximation and neutrino mass models to decrease the constraining power of photometric galaxy surveys and cause parameter biases in the cosmological interpretation of future surveys. We quantify these biases and devise mitigation strategies.

Extensive air showers induced from high-energy cosmic rays provide a window into understanding the most energetic phenomena in the universe. We present a new method for observing these showers using the silicon imaging detector Subaru Hyper Suprime-Cam (HSC). This method has the advantage of being able to measure individual secondary particles. When paired with a surface detector array, silicon imaging detectors like Subaru HSC will be useful for studying the properties of extensive air showers in detail. The following report outlines the first results of observing extensive air showers with Subaru HSC. The potential for reconstructing the incident direction of primary cosmic rays is demonstrated and possible interdisciplinary applications are discussed.

The signal to noise ratio efficiency $\epsilon_{\rm SNR}$ in axion dark matter searches has been estimated using large-statistic simulation data reflecting the background information and the expected axion signal power obtained from a real experiment. This usually requires a lot of computing time even with the assistance of powerful computing resources. Employing a Savitzky-Golay filter for background subtraction, in this work, we estimated a fully analytical $\epsilon_{\rm SNR}$ without relying on large-statistic simulation data, but only with an arbitrary axion mass and the relevant signal shape information. Hence, our work can provide $\epsilon_{\rm SNR}$ using minimal computing time and resources prior to the acquisition of experimental data, without the detailed information that has to be obtained from real experiments. Axion haloscope searches have been observing the coincidence that the frequency independent scale factor $\xi$ is approximately consistent with the $\epsilon_{\rm SNR}$. This was confirmed analytically in this work, when the window length of the Savitzky-Golay filter is reasonably wide enough, i.e., at least 5 times the signal window.

It has been shown in previous publications that the TNG100 simulation quantitatively reproduces the observed reduction in each of the total atomic and total molecular hydrogen gas for galaxies within massive halos, i.e.~dense environments. In this Letter, we study how well TNG50 reproduces the resolved effects of a Virgo-like cluster environment on the gas surface densities of satellite galaxies with $m_* > \! 10^9\,{\rm M}_\odot$ and ${\rm SFR} \! > 0.05\,{\rm M}_\odot\,{\rm yr}^{-1}$. We select galaxies in the simulation that are analogous to those in the HERACLES and VERTICO surveys, and mock-observe them to the common specifications of the data. Although TNG50 does not quantitatively match the observed gas surface densities in the centers of galaxies, the simulation does qualitatively reproduce the trends of gas truncation and central density suppression seen in VERTICO in both HI and H$_2$. This result promises that modern cosmological hydrodynamic simulations can be used to reliably model the post-infall histories of cluster satellite galaxies.

Since self-gravity is crucial in the structure formation of the universe, many hydrodynamics simulations with the effect of self-gravity have been conducted. The multigrid method is widely used as a solver for the Poisson equation of the self-gravity; however, the parallelization efficiency of the multigrid method becomes worse when we use a massively parallel computer, and it becomes inefficient with more than $10^4$ cores, even for highly tuned codes. To perform large-scale parallel simulations ($> 10^4$ cores), developing a new gravity solver with good parallelization efficiency is beneficial. In this article, we develop a new self-gravity solver using the telegraph equation with a damping coefficient, $\kappa$. Parallelization is much easier than the case of the elliptic Poisson equation since the telegraph equation is a hyperbolic partial differential equation. We analyze convergence tests of our telegraph equations solver and determine that the best non-dimensional damping coefficient of the telegraph equations is $\tilde{\kappa} \simeq 2.5$. We also show that our method can maintain high parallelization efficiency even for massively parallel computations due to the hyperbolic nature of the telegraphic equation by weak-scaling tests. If the time step of the calculation is determined by heating/cooling or chemical reactions, rather than the CFL condition, our method may provide the method for calculating self-gravity faster than other previously known methods such as the fast Fourier transform and multigrid iteration solvers because gravitational phase velocity determined by the CFL condition using these timescales is much larger than the fluid velocity plus sound speed.

We report the derivation of rate coefficients for the rotational (de-)excitation of PO$^+$ induced by collisions with H$_2$. The calculations were performed on a four-dimensional potential energy surface, obtained on top of highly accurate $ab$ $initio$ energy points. Preliminary tests pointed out the low influence of the coupling between $j=0$ and the higher rotational levels of H$_2$ on the cross sections values, thus allowing to neglect the rotational structure of H$_2$. On this basis, state-to-state collisional rate coefficients were derived for temperatures ranging from 5 to 200 K. Radiative transfer calculations have been used to model the recent observation of PO$^+$ in the G+0.693-0.027 molecular cloud, in order to evaluate the possible impact of non-LTE models on the determination of its physical conditions. The derived column density was found to be approximately $\sim 3.7\times10^{11}$ cm$^{-2}$, which is 60\% (a factor of $\sim 1.7$) smaller than the previously LTE-derived value. Extensive simulations show that PO$^+$ low-$j$ rotational lines exhibit maser behavior at densities between $10^4$ and $10^6$ cm$^{-3}$, thus highlighting the importance of a proper treatment of the molecular collisions to accurately model PO$^+$ emissions in the interstellar medium.

We present a high resolution numerical study of the sinking and merging of massive black holes (MBHs) with masses in the range of $10^3 - 10^7 \, \mathrm{M}_\odot$ in multiple minor mergers of low mass dark matter halos without and with galaxies ($4\times 10^8 \, \mathrm{M}_\odot \lesssim \mathrm{M}_{\mathrm{halo}} \lesssim 2\times 10^{10} \, \mathrm{M}_\odot)$. The Ketju simulation code, a combination of the Gadget tree solver with accurate regularised integration, uses unsoftened forces between the star/dark matter components and the MBHs for an accurate treatment of dynamical friction and scattering of dark matter/stars by MBH binaries or multiples. Post-Newtonian corrections up to order 3.5 for MBH interactions allow for coalescence by gravitational wave emission and gravitational recoil kicks. Low mass MBHs ($\lesssim 10^5 \, \mathrm{M}_\odot$) hardly sink to the centre or merge. Sinking MBHs have various complex evolution paths - binaries, triplets, free-floating MBHs, and dynamically or recoil ejected MBHs. Collisional interactions with dark matter alone can drive MBHs to coalescence. The highest mass MBHs of $\gtrsim 10^6 M_\odot$ mostly sink to the centre and trigger the scouring of dark matter and stellar cores. The scouring can transform a centrally baryon dominated system to a dark matter dominated system. Our idealized high-resolution study highlights the difficulty to bring in and keep low mass MBHs in the centres of low mass halos/galaxies - a remaining challenge for merger assisted MBH seed growth mechanisms.

We have carried out ALMA observations of the massive star-forming region W75N(B), which contains the massive protostars VLA1, VLA2, and VLA3. Particularly, VLA2 is an enigmatic protostar associated with a wind-driven H$_2$O maser shell, which has evolved from an almost isotropic outflow to a collimated one in just 20 years. The shell expansion seemed to be halted by an obstacle located to the northeast of VLA2. Here we present our findings from observing the 1.3~mm continuum and H$_2$CO and SiO emission lines. Within a region of ~30" (~39,000 au) diameter, we have detected 40 compact mm-continuum sources, three of them coinciding with VLA1, VLA2, and VLA3. While the H$_2$CO emission is mainly distributed in a fragmented structure around the three massive protostars, but without any of the main H$_2$CO clumps spatially coinciding with them, the SiO is highly concentrated on VLA2, indicating the presence of very strong shocks generated near this protostar. The SiO emission is clearly resolved into an elongated structure (~ 0.6"*0.3"; ~780 au * 390 au) perpendicular to the major axis of the wind-driven maser shell. The structure and kinematics of the SiO emission are consistent with a toroid and a wide-angle outflow surrounding a central mass of ~10 Msun, thus supporting previous theoretical predictions regarding the evolution of the outflow. Additionally, we have identified the expected location and estimated the gas density of the obstacle that is hindering the expansion of the maser shell.

RadioTalk is a communication platform that enabled members of the Radio Galaxy Zoo (RGZ) citizen science project to engage in discussion threads and provide further descriptions of the radio subjects they were observing in the form of tags and comments. It contains a wealth of auxiliary information which is useful for the morphology identification of complex and extended radio sources. In this paper, we present this new dataset, and for the first time in radio astronomy, we combine text and images to automatically classify radio galaxies using a multi-modal learning approach. We found incorporating text features improved classification performance which demonstrates that text annotations are rare but valuable sources of information for classifying astronomical sources, and suggests the importance of exploiting multi-modal information in future citizen science projects. We also discovered over 10,000 new radio sources beyond the RGZ-DR1 catalogue in this dataset.

While the data analysis of $\gamma$-ray telescopes has now become more robust, some signals may be misinterpretations of a time-variable foreground emission from the Solar System, induced by low-energy cosmic-ray interactions with asteroids. Our goal is to provide emission templates for this time-variable diffuse $\gamma$-ray foreground by considering the populations of Main Belt Asteroids, Jovian and Neptunian Trojans, Kuiper Belt Objects, and the Oort Cloud. We model the spatial distribution of all known asteroids by performing 3D-fits to determine their density profiles and calculate their appearances by line-of-sight integrations. Because Earth and the asteroids are moving with respect to each other, we obtain diffuse emission templates varying on timescales of days to decades. We find that the temporal variability can lead to flux enhancements which may mimic emission features unless properly taken into account. This variation is further enhanced by the Solar cycle as the cosmic-ray spectrum is attenuated by the Solar modulation potential, leading to a relative flux increase of the outer asteroids. The cumulative effect of the time-dependent emission is illustrated for the case of the 511 keV OSSE fountain, and for emission features near the Galactic Centre, both being possible misinterpretations of the Solar System albedo. We recommend that $\gamma$-ray data analyses should always take into account the possibility of a time-variable foreground. Due to the ecliptic overlap with the Galactic plane, the Galactic emission is expected to be weaker by 0.1-20%, depending on time (relative planetary motion), energy, and Solar cycle, which has immense consequences for the interpretation of dark matter annihilation cross sections, cosmic-ray spectra and amplitudes, as well as nucleosynthesis yields and related parameters.

Context. Type II radio bursts are solar radio burst associated with coronal shocks. Type II bursts usually exhibit fine structures in dynamic spectra that represent signatures of accelerated electron beams. So far, the sources of individual fine structures in type II bursts have not been spatially resolved in high-resolution low-frequency radio imaging. Aims. The objective of this study is to resolve the radio sources of the herringbone bursts found in type II solar radio bursts and investigate the properties of the acceleration regions in coronal shocks Methods. We use low-frequency interferometric imaging observations from the Low Frequency Array (LOFAR) to provide a spatially resolved analysis for three herringbone groups (marked as A, B, and C) in a type II radio burst that occurred on 2015 October 16th. Results. The herringbones in groups A and C have a undiversified frequency drift direction and propagation direction along frequency. They have similar value of frequency drift rates corresponding to that of type III bursts and previously studied herringbones. Group B has a more complex spatial distribution, with two distinct sources separated by 50 arcsec and no clear spatial propagation with frequency. One of the herringbones in group B was found to have an exceptionally large frequency drift rate. Conclusions. The characteristics deroved from imaging spectroscopy suggest that the studied herringbones originate from different processes. The herringbone groups A and C most likely originate from single-direction beam electrons, while group B may be explained by counterstreaming beam electrons

We investigate expected constraints on the primordial tensor power spectrum from the future cosmic microwave background polarization experiment LiteBIRD as a test of multi-field inflation. We argue that the measurements of the tensor-to-scalar ratio and the tensor spectral index, in combination with the constraints on the scalar spectral index from the Planck observation, are useful in testing multi-field inflation models. We also discuss implications for multi-field inflationary model building.

TIPTOP is a python library that is able to quickly compute Point Spread Functions (PSF) of any kind of Adaptive Optics systems. This library has multiple objectives: support the exposure time calculators of future VLT and ELT instruments, support adaptive optics systems design activities, be part of PSF reconstruction pipelines and support the selection of the best asterism of natural guide stars for observation preparation. Here we report one of the last improvements of TIPTOP: the introduction of the error given by a single conjugated laser, commonly known as the cone effect. The Cone effect was not introduced before because it is challenging due to the non-stationarity of the phase. Laser guide stars are at a finite distance with respect to the telescope and probe beam accepted by the wavefront sensor has the shape of a cone. Given a single spatial frequency in an atmospheric layer, the cone effect arises from the apparent magnification or stretching of this frequency when it reaches the wavefront sensor. The magnification effect leads to an incorrect estimation of the spatial frequency. Therefore, we estimate the residual power by calculating the difference between two sinusoids with different periods: the nominal one and the magnified one. Replicating this for each spatial frequency we obtain the power spectrum associated with the cone effect. We compare this estimation with the one given by end-to-end simulation and we present how we plan to validate this with on-sky data.

Weak gravitational lensing is an important tool to estimate the masses of galaxy clusters, as it allows us to directly access their projected surface mass density along the line-of-sight (LOS) in a manner largely independent of their dynamical state. Moreover, we can extract information on the projected shape of the cluster mass distribution. In this work, we generate mock catalogs of lensed background galaxies to measure the individual lensing properties of galaxy clusters from the simulation project The Three Hundred. By repeating the analysis for different projections of the same cluster, we find that the use of shear multipoles provides constraints on the ellipticity of the cluster projected mass density but does not have a significant impact on the cluster mass reconstruction compared to the standard approach.

We studied the unique kinematic properties in massive filament G352.63-1.07 at $10^3$-AU spatial scale with the dense molecular tracers observed with the Atacama Large Millimeter/submillimeter Array (ALMA). We find the central massive core M1 (12 $M_\odot$) being separated from the surrounding filament with a velocity difference of $v- {v}_{sys}=-2$ km/s and a transverse separation within 3 arcsec. Meanwhile, as shown in multiple dense-gas tracers, M1 has a spatial extension closely aligned with the main filament and is connected to the filament towards its both ends. M1 thus represents a very beginning state for a massive young star-forming core escaping from the parental filament, within a time scale of $\sim 4000$ years. Based on its kinetic energy ($3.5\times10^{44}$ erg), the core escape is unlikely solely due to the original filament motion or magnetic field, but requires more energetic events such as a rapid intense anisotropic collapse. The released energy also seems to noticeably increase the environmental turbulence. This may help the filament to become stabilized again.

MORFEO (Multi-conjugate adaptive Optics Relay For ELT Observation) is the future multi-conjugate adaptive optics system for the ESO ELT that will feed the instrument MICADO (Multi-AO Imaging Camera for Deep Observations). It will use the 6 laser guide stars to give a uniform correction on a field-of-view of approximately 60arcsec of diameter. Tip, tilt and slow focus measurement will be done on up to three natural guide stars that could be really faint to maximize sky coverage. The current baseline is to use the reference wavefront sensor in the visible to acquire the star and center it on the low order wavefront sensor that has a much smaller field-of-view. In this work we study this problem focusing on the estimation error of the tilt from the reference wavefront sensor as a function of star magnitude and atmospheric conditions.

Black widows (BWs) are millisecond pulsars ablating their companion stars. The out-flowing material from the companion can block the radio emission of the pulsar, resulting in eclipses. In this paper, we construct a model for the radio eclipse by calculating the geometry of the bow shock between the winds of the pulsar and companion, where the shock shapes the eclipsing medium but had not been described in detail in previous works. The model is further used to explain the variations of the flux density and dispersion measure (DM) of three BW pulsars (i.e., PSR B1957$+$20, J2055$+$3829, and J2051$-$0827) detected by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Consequently, we constrained the parameters of the three BW systems such as the inclination angles and true anomalies of the observer as well as the mass-loss rates and wind velocity of the companion stars. With the help of these constraints, it is expected that magnetic fields of companion stars and even masses of pulsars could further be determined as some extra observation can be achieved in the future.

Compositional convection is atmospheric mixing driven by density variations caused by compositional gradients. Previous studies have suggested that compositional gradients of atmospheric trace species within planetary atmospheres can impact convection and the final atmospheric temperature profile. In this work, we employ 3D convection resolving simulations using Cloud Model 1 (CM1) to gain a fundamental understanding of how compositional variation influences convection and the final atmospheric state of exoplanet atmospheres. We perform 3D initial value problem simulations of non-condensing compositional convection for Earth-Air, $\rm H_2$, and $\rm CO_2$ atmospheres. Conventionally, atmospheric convection is assumed to mix the atmosphere to a final, marginally stable state defined by a unique temperature profile. However, when there is compositional variation within an atmosphere, a continuous family of stable end states is possible, differing in the final state composition profile. Our CM1 simulations are used to determine which of the family of possible compositional end states is selected. Leveraging the results from our CM1 simulations, we develop a dry convective adjustment scheme for use in General Circulation Models (GCMs). This scheme relies on an energy analysis to determine the final adjusted atmospheric state. Our convection scheme produces results that agree with our CM1 simulations and can easily be implemented in GCMs to improve modelling of compositional convection in exoplanet atmospheres.

A gamma-ray burst, named GRB 221009A, occurred on 9 October 2022 and is the brightest ever observed GRB, whose frequency is now estimated as once in 10,000 years. This GRB was reported to be observed from many space missions, VLF receivers, and ground observations in optical and radio data. Additionally, a strikingly large number of very high energy (VHE) photons associated with this GRB were observed by the gamma-ray and cosmic ray observatory LHAASO. Though gamma rays of cosmic origin usually tend to be absorbed by the atmosphere, the high fluence of this GRB, along with the observation of more than 5000 VHE photons (0.5 to 18 TeV) by LHAASO from the ground, emphasises the need to explore other possible ground observations of this GRB. The present paper examines the effect of this GRB using gamma-ray data in a low energy range (0.2-6) MeV obtained using NaI (Tl) detectors located at Tirunelveli (Geographic coordinates: 8.71{\deg}N, 77.76{\deg}E), India. With RA = 288.3{\deg} and Dec = 19.8{\deg}, the exceptionally bright fluence of this GRB was geographically centred on India. We report no significant change in the observations associated with GRB 221009A. We discuss the extent of attenuation of gamma rays in the atmosphere that could explain the reported observations. Further, we estimate the parameters of a hypothetical GRB for which photons of similar energies would reach the ground.

Aims: Using 2D Mgii h&k solar prominence modelling, our aim is to understand the formation of complex line profiles and how these are seen by the Interface Region Imaging Spectrograph (IRIS). Additionally, we see how the properties of these simulated observations are interpreted through the use of traditional 1D prominence modelling. Methods: We used a cylindrical non-local thermodynamic equilibrium (NLTE) 2D complete redistribution (CRD) code to generate a set of cylindrical prominence strands, which we stacked behind each other to produce complex line profiles. Then, with the use of the point spread functions (PSFs) of IRIS, we were able to predict how IRIS would observe these line profiles. We then used the 1D NLTE code PROM in combination with the Cross Root Mean Square method (xRMS) to find the properties recovered by traditional 1D prominence modelling. Results: Velocities of magnitude lower than 10 km/s are sufficient to produce asymmetries in the Mgii h&k lines. However, convolution of these with the PSFs of IRIS obscures this detail and returns standard looking single peaks. By increasing the velocities by a factor of three, we recover asymmetric profiles even after this convolution. The properties recovered by xRMS appear adequate at first, but the line profiles chosen to fit these profiles do not satisfactorily represent the line profiles. This is likely due to the large line width of the simulated profiles. Conclusions: Asymmetries can be introduced by multithread models with independent Doppler velocities. The large line width created by these models makes it difficult for traditional 1D forward modelling to find good matches. This may also demonstrate degeneracies in the solution recovered by single-species 1D modelling.

We present the results of a 5-year monitoring program of 42 sources targeted at 6.7 GHz methanol masers, conducted from March 2017 to October 2022 using the Irbene 32 and 16 meter radio telescopes. Sources were observed with irregular intervals where time between two consecutive observation ranged from twenty four hours to thirty five days. We found that more than 55 per cent of the sources showed significant variability, but often only one or a few spectral features were varying significantly. Numerous type of variability were found in our sample: low-variable, periodic, irregular, synchronised and anti-correlated between features and steadily raising or falling flux. Our analysis techniques also uncover new variability trends for several sources. The maser monitoring program is one of the first single-dish science initiatives at the Irbene radio telescope complex, initiated shortly after the instrument's reconstruction and upgrades. Our findings unequivocally demonstrate its suitability for maser research purposes.

We present LimberJack.jl, a fully auto-differentiable code for cosmological analyses of 2 point auto- and cross-correlation measurements from galaxy clustering, CMB lensing and weak lensing data written in Julia. Using Julia's auto-differentiation ecosystem, LimberJack.jl can obtain gradients for its outputs up to an order of magnitude faster than traditional finite difference methods. This makes LimberJack.jl greatly synergistic with gradient-based sampling methods, such as Hamiltonian Monte Carlo, capable of efficiently exploring parameter spaces with hundreds of dimensions. We first prove LimberJack.jl's reliability by reanalysing the DES Y1 3$\times$2-point data. We then showcase its capabilities by using a O(100) parameters Gaussian Process to reconstruct the cosmic growth from a combination of DES Y1 galaxy clustering and weak lensing data, eBOSS QSO's, CMB lensing and redshift-space distortions. Our Gussian process reconstruction of the growth factor is statistically consistent with the $\Lambda$CDM Planck 2018 prediction at all redshifts. Moreover, we show that the addition of RSD data is extremely beneficial to this type of analysis, reducing the uncertainty in the reconstructed growth factor by $20\%$ on average across redshift. LimberJack.jl is a fully open-source project available on Julia's general repository of packages and GitHub.

Stratified disks with strong horizontal magnetic fields are susceptible to magnetic buoyancy instability (MBI). Modifying the magnetic field and gas distributions, this can play an important role in galactic evolution. The MBI and the Parker instability, in which cosmic rays exacerbate MBI, are often studied using an imposed magnetic field. However, in galaxies and accretion discs, the magnetic field is continuously replenished by a large-scale dynamo action. Using non-ideal MHD equations, we model a section of the galactic disc (we neglect rotation and cosmic rays considered elsewhere), in which the large-scale field is generated by an imposed $\alpha$-effect of variable intensity to explore the interplay between dynamo instability and MBI. The system evolves through three distinct phases: the linear (kinematic) dynamo stage, the onset of linear MBI when the magnetic field becomes sufficiently strong and the nonlinear, statistically steady state. Nonlinear effects associated with the MBI introduce oscillations which do not occur when the field is produced by the dynamo alone. The MBI initially accelerates the magnetic field amplification but the growth is quenched by the vertical motions produced by MBI. We construct a 1D model, which replicates all significant features of 3D simulations to confirm that magnetic buoyancy alone can quench the dynamo and is responsible for the magnetic field oscillations. Unlike with an imposed magnetic field (arXiv:2305.03318,arXiv:2212.03215), the nonlinear interactions do not reduce the gas scale height, so the consequences of the magnetic buoyancy depend on how the magnetic field is maintained.

Planets grow in rotating disks of dust and gas around forming stars, some of which can subsequently collide in giant impacts after the gas component is removed from the disk. Monitoring programs with the warm Spitzer mission have recorded significant and rapid changes in mid-infrared output for several stars, interpreted as variations in the surface area of warm dusty material ejected by planetary-scale collisions and heated by the central star: e.g., NGC 2354-ID8, HD 166191 and V844 Persei. Here we report combined observations of the young (about 300 Myr), solar-like star ASASSN-21qj: an infrared brightening consistent with a blackbody temperature of 1000 K and a luminosity of 4 percent of that of the star lasting for about 1000 days, partially overlapping in time with a complex and deep wavelength-dependent optical eclipse that lasted for about 500 days. The optical eclipse started 2.5 years after the infrared brightening, implying an orbital period of at least that duration. These observations are consistent with a collision between two exoplanets of several to tens of Earth masses at 2 to 16 au from the central star. Such an impact produces a hot, highly-extended post-impact remnant with sufficient luminosity to explain the infrared observations. Transit of the impact debris, sheared by orbital motion into a long cloud, causes the subsequent complex eclipse of the host star.

General relativity predicts that gravitational waves propagate at the speed of light. Although ground-based gravitational-wave detectors have successfully constrained the velocity of gravitational waves in the high-frequency range, extending this constraint to the lower frequency range remains a challenge. In this work, we utilize the deviations in the overlap reduction function for a gravitational-wave background within pulsar timing arrays to investigate the velocity of gravitational waves in the nanohertz frequency band. By analyzing the NANOGrav 15-year data set, we obtain a well-constrained lower bound for the velocity of gravitational waves that $v \gtrsim 0.87\,c$, where $c$ is the speed of light.

We present the results of an analysis aimed at probing the small-scale magnetic fields of M dwarfs observed with SPIRou, the nIR high-resolution spectro-polarimeter installed at the Canada-France-Hawaii Telescope, in the context of the SPIRou Legacy Survey. Our analysis relies on high-resolution median spectra built from several tens of spectra recorded between 2019 and 2022, and on synthetic spectra computed with the ZeeTurbo code for various combination of atmospheric parameters and magnetic field strengths. We pursue the efforts undertaken in a previous study and focus on 44 weakly to moderately active M dwarfs. We derive average magnetic field strengths (<$B$>) ranging from 0.05 to 1.15 kG, in good agreement with activity estimates and rotation periods. We found that including magnetic fields in our models has virtually no impact on our derived atmospheric parameters, and that a priori assumptions on the stellar surface gravity can affect our estimated <$B$>. Our results suggest that small-scale magnetic fields account for more than 70% of the overall average magnetic field for most targets whose large-scale fields were previously measured. We derived low magnetic fluxes for several targets in our sample, and found no clear evidence that <$B$> decreases with increasing Rossby number in the unsaturated dynamo regime. We even identified counterexamples (GJ 1289 and GJ 1286) where the small-scale field is unusually strong despite the long rotation period. Along with similar results on the large-scale fields, our findings further suggest that dynamo processes may operate in a non-conventional mode in these strongly magnetic, slowly-rotating stars.

Aims. We aim to improve a previous model for the prediction of column densities and deuterium fractions of non- and singly deuterated methanol. Thereby, we try to identify crucial chemical and physical parameters, for which the study of deuteration could provide valuable additional constraints. Methods. We employed a gas-grain chemical code to devise a model that is in agreement with the observed column density and deuterium fraction profiles of the innermost region of the pre-stellar core L1544. For that purpose, we developed a new treatment of reactive desorption, deriving an individual reactive desorption efficiency for every product species in a chemical reaction, that depends on the reaction enthalpy and type of underlying surface. Furthermore, we explored several options to promote the diffusion of hydrogen and deuterium atoms over the surface of interstellar dust grains, in order to increase methanol formation. Results. Our fiducial model employs diffusion by quantum tunneling of hydrogen and deuterium atoms, resulting in CH$_3$OH and CH$_2$DOH column densities that are approximately an order of magnitude lower than the observed values, which improves the results compared to the previous model by a factor 10. The $N$(CH$_2$DOH)/$N$(CH$_3$OH) ratio is reproduced within a factor of 1.2 for the centre and 1.8 for the position of the methanol peak. Given the large uncertainties that chemical models typically have, we consider our predictions to be in agreement with the observations. In general, we conclude that a diffusion process with a high diffusion rate needs to be employed to obtain methanol column densities that are in accordance with the observed values. Also, we find that the introduction of abstraction reactions into the methanol formation scheme suppresses deuteration, when used in combination with a high diffusion rate.

We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of nine most metal-deficient compact star-forming galaxies with oxygen abundances 12+log(O/H)=6.97-7.23, redshifts z=0.02811-0.13320, and stellar masses M*<10^7Msun. We aim to study the properties of Ly-alpha emission in these extremely metal-deficient objects. We find that all nine galaxies are Ly-alpha emitters (LAEs). We examine various relations between the Ly-alpha escape fraction fesc(Ly-alpha) and other characteristics - such as absolute UV magnitude, oxygen abundance, O32 ratio, stellar mass, Lyman-alpha luminosity and equivalent width EW(Ly-alpha), ionizing photon production efficiency and velocity separation Vsep between the two peaks of the Ly-alpha profile - of a large sample of LAEs, including our lowest-metallicity galaxies and other objects from the literature. We find a relatively tight correlation between fesc(Ly-alpha) and two characteristics, EW(Ly-alpha) and Vsep, whereas no correlation is found between fesc(Ly-alpha) and the oxygen abundance. We also find a relatively tight relation between the Ly-alpha and LyC escape fractions. We propose to use the latter relation to estimate indirectly the escaping ionizing radiation in LAEs, when direct measurements of LyC emission are not possible. We show that the global properties of low-z LAEs are very similar to those of z>6 galaxies. They are thus ideal local proxies for studying physical processes during the epoch of reionization of the Universe.

We explore the growth of the stellar disks in 14 nearby spiral galaxies as part of the Deciphering the Interplay between the Interstellar medium, Stars, and the Circumgalactic medium (DIISC) survey. We study the radial distribution of specific star formation rates (sSFR) and investigate the ratio of the difference in the outer and inner sSFR ($\Delta_{sSFR}~={\rm sSFR}_{out}-{\rm sSFR}_{in}$) of the disk and the total sSFR, $\Delta_{sSFR}$/sSFR to quantify disk growth. We find $\Delta_{sSFR}$/sSFR and the HI gas fraction to show a mild correlation of Spearman's $\rho=0.30$, indicating that star formation and disk growth are likely to proceed outward in galactic disks with high HI gas fractions. The HI gas fractions and $\Delta_{sSFR}$/sSFR of the galaxies also increase with the distance to the nearest L$_\star$ neighbor, suggesting that galaxies are likely to sustain their ISM cold gas and exhibit inside-out growth in isolated environments. However, the HI content in their circumgalactic medium, probed by the Ly$\alpha$ equivalent width (W$_{Ly\alpha}$) excess, is observed to be suppressed in isolated environments, apparent from the strong anti-correlation between the W$_{Ly\alpha}$ excess and the distance to the 5$^{\rm th}$ nearest L$_\star$ neighbor (Spearman's $\rho=-0.62$). As expected, W$_{Ly\alpha}$ is also found to be suppressed in cluster galaxies. We find no relation between the W$_{Ly\alpha}$ excess of the detected CGM absorber and $\Delta_{sSFR}$/sSFR implying that the enhancement and suppression of the circumgalactic HI gas does not affect the direction in which star formation proceeds in a galactic disk or vice-versa.

We provide a complementary nested sampling analysis for the Atacama Cosmology Telescope lensing data release 6. This allows the quantification of global consistency statistics between ACT lensing and alternative datasets. In the context of flat $\Lambda$CDM, we find no inconsistency between ACT, Baryonic Acoustic Oscillations, Planck anisotropies, weak lensing datasets, or NPIPE lensing. As part of our analysis, we also investigate the effect of the prior widths used in the ACT analysis and find that the headline results are quantitatively but not qualitatively affected by the chosen priors. We use both Bayes factors and the suspiciousness statistic to quantify the possibility of tension, and find suspiciousness unsuitable in the case of strong agreement between ACT DR6 and NPIPE. Nested sampling provides a competitive alternative to Metropolis Hastings and we recommend it be used alongside existing analyses. We release the chains and plotting source for the analysis using anesthetic.

Dark GRBs constitute a significant fraction of the GRB population. In this paper, we present the multiwavelength analysis of an intense two-episodic GRB 150309A observed early on to ~114 days post-burst. Despite the strong gamma-ray emission, no optical afterglow was detected for this burst. However, we discovered near-infrared afterglow ($K_{\rm S}$-band), ~5.2 hours post burst, with the CIRCE instrument mounted at the 10.4m GTC. We used Fermi observations of GRB 150309A to understand the prompt emission mechanisms and jet composition. We performed the early optical observations using the BOOTES robotic telescope and late-time afterglow observations using the GTC. A potential faint host galaxy is also detected at optical wavelength using the GTC. We modelled the potential host galaxy of GRB 150309A in order to explore the environment of the burst. The time-resolved spectral analysis of Fermi data indicates a hybrid jet composition consisting of a matter-dominated fireball and magnetic-dominated Poynting flux. GTC observations of the afterglow revealed that the counterpart of GRB 150309A was very red, with H-$K_{\rm S}$ > 2.1 mag (95 $\%$ confidence). The red counterpart was not discovered in any bluer filters of Swift UVOT, indicative of high redshift origin. This possibility was discarded based on multiple arguments, such as spectral analysis of X-ray afterglow constrain z < 4.15 and a moderate redshift value obtained using spectral energy distribution modelling of the potential galaxy. The broadband afterglow SED implies a very dusty host galaxy with deeply embedded GRB (suggesting $A_{\rm V}$ $\gtrsim$ 35 mag). The environment of GRB 150309A demands a high extinction towards the line of sight, demanding dust obscuration is the most probable origin of optical darkness and the very red afterglow of GRB 150309A. This result makes GRB 150309A the highest extinguished GRB known to date.

Spinel (MgAl$_{2}$O$_{4}$) and krotite (CaAl$_{2}$O$_{4}$) are alternative candidates to alumina (Al$_2$O$_3$) as primary dust condensates in the atmospheres of oxygen-rich evolved stars. Moreover, spinel was proposed as a potential carrier of the circumstellar 13 $\mu$m feature. However, the formation of nucleating spinel clusters is challenging; in particular, the inclusion of Mg constitutes a kinetic bottleneck. We aim to understand the initial steps of cosmic dust formation (i.e. nucleation) in oxygen-rich environments using a quantum-chemical bottom-up approach. Starting with an elemental gas-phase composition, we constructed a detailed chemical-kinetic network that describes the formation and destruction of magnesium-, calcium-, and aluminium-bearing molecules as well as the smallest dust-forming (MgAl$_{2}$O$_{4}$)$_1$ and (CaAl$_{2}$O$_{4}$)$_1$ monomer clusters. Different formation scenarios with exothermic pathways were explored, including the alumina (Al$_2$O$_3$) cluster chemistry studied in Paper I of this series. The resulting extensive network was applied to two model stars, a semi-regular variable and a Mira-type star, and to different circumstellar gas trajectories, including a non-pulsating outflow and a pulsating model. We employed global optimisation techniques to find the most favourable (MgAl$_2$O$_4$)$_n$, (CaAl$_2$O$_4$)$_n$, and mixed (Mg$_x$Ca$_{(1-x)}$Al$_2$O$_4$)$_n$ isomers, with $n$=1$-$7 and x$\in$[0..1], and we used high level quantum-chemical methods to determine their potential energies. The growth of larger clusters with $n$=2$-$7 is described by the temperature-dependent Gibbs free energies.In the considered stellar outflow models, spinel clusters do not form in significant amounts. However, we find that in the Mira-type non-pulsating model CaAl$_2$O$_3$(OH)$_2$, a hydroxylated form of the calcium aluminate krotite monomer forms ...

We present a protocluster search covering $z\sim3$ to $z\sim5$ based on the combination of the Hyper SuprimeCam Subaru Strategic Programme and the CFHT Large Area $U$-band Deep Survey. We identify about 30 protocluster candidates per unit redshift over the $\sim25\,\mathrm{deg^2}$ area of the Deep/Ultra-Deep layer. Protocluster candidates are selected as regions with a significantly enhanced surface density of dropout galaxies. With this large sample, we characterise the properties of their individual member galaxies. We compare the number counts of dropout galaxies in protocluster candidates with that of coeval field galaxies. Rest-frame UV bright galaxies are over-abundant in protocluster candidates, a trend seen across the full redshift range studied. We do not find evidence for their spatial distribution within protocluster candidates to be distinct from their fainter counterparts, nor for their UV colour to be different from that of field galaxies with the same brightness. Cosmological simulations predict this bright-end excess, with the main cause being a richer population of massive galaxies, with only a minor contribution from an enhancement in star formation activity (and therefore UV emission) at fixed mass. $U$-to-$K$ SED modelling of our observed samples supports this interpretation. This environmental differentiation in number counts is already in place at $z\sim5$, with no significant redshift dependence over the range in lookback times probed. These observational results and model predictions suggest that the cosmic clock is ahead in high-density environments.

Gravitational Waves (GW) sourced by second-order primordial curvature fluctuations are among the favoured models fitting the recent Pulsar Timing Array (PTA) measurement of a Stochastic GW Background (SGWB). We study how spectral distortions (SDs) and anisotropies of the Cosmic Microwave Background (CMB) can constrain such scalar fluctuations. Whereas COBE FIRAS data have no sufficient sensitivity to probe the PTA lognormal hypothesis, we show how future PIXIE-like experiments can detect the CMB SDs from the scalar-induced interpretation of the SGWB in PTA data. We finally show how the transformative synergy between PTA data and future CMB SD measurements is important for reconstructing primordial fluctuations at these small scales.

We aimed to build a new and updated C0-C2 chemical network to study the CHON disequilibrium chemistry of warm and hot exoplanet atmospheres that relies on extensively validated and recent state-of-the-art combustion networks. The reliability range of this network was aimed for conditions between 500 - 2500 K and 100 - 10^-6 bar. We compared the predictions of seven networks over a large set of experiments, covering a wide range of conditions (pressures, temperatures, and initial compositions). To examine the consequences of this new chemical network on exoplanets atmospheric studies, we generated abundances profiles for GJ 436 b, GJ 1214 b, HD 189733 b, and HD 209458 b, using the 1D kinetic model FRECKLL and calculated the corresponding transmission spectra using TauREx 3.1. These spectra and abundance profiles have been compared with results obtained with our previous chemical network. Our new kinetic network is composed of 174 species and 1293 reactions mostly reversible. This network proves to be more accurate than our previous one for the tested experimental conditions. The nitrogen chemistry update is found to be impactful on the abundance profiles, particularly for HCN, with differences up to four orders of magnitude. The CO2 profiles are also significantly affected, with important repercussions on the transmission spectrum of GJ 436 b. These effects highlight the importance of using extensively validated chemical networks to gain confidence in our models predictions. As shown with CH2NH, the coupling between carbon and nitrogen chemistry combined with radicals produced by photolysis can have huge effects impacting the transmission spectra.

Diverse protoplanetary disk morphology can result from planet-disk interaction, suggesting planetary presence. To date, most scattered light imaging campaigns have probed polarized light, which is only a fraction of the total light and not very sensitive to planets. To observe and characterize protoplanetary disk systems in the near-infrared in both polarized and total intensity light, we carried out an unprecedented study of scattering properties of disks, as well as of any planetary companions. Using SPHERE with star-hopping at the Very Large Telescope, we observed 29 disk hosts and their reference stars in $K_s$-band polarized light. We extracted disks in total intensity by adopting the data imputation concept with sequential non-negative matrix factorization (DI-sNMF). We obtained high-quality disk images in total intensity for 15 systems and in polarized light for 23. For well-recovered disks in polarized light and total intensity, we parameterized the polarization fraction phase functions using scaled beta distribution: the peak of polarization fraction tentatively correlates with the peak scattering angle, which could be reproduced using certain compact dust, yet more detailed modeling studies are needed. We investigated the empirical DI-sNMF detectability of disks using logistic regression: total intensity detectability of disks primarily depends on host star brightness. For disks with SPHERE data in $Y$-/$J$-/$H$-band, we summarized their polarized color at ~90 deg scattering angle: most of disks are blue in polarized $J-K_s$ color, and they are relatively redder as stellar luminosity increases, indicating larger scatterers. High-quality disk imagery in both total intensity and polarized light thus allows for disk characterization in polarization fraction, and reduces the confusion between disk and planetary signals.

Binary-black-hole (BBH) mergers can take place close to a supermassive black hole (SMBH) while being in a bound orbit around the SMBH. In this paper, we study such bound triple systems and show that including the strong gravity effects of describing the SMBH with a Kerr metric can significantly modify the dynamics, as compared to a Newtonian point particle description of the SMBH. We extract the dynamics of the system, using a quadrupole approximation to the tidal forces due to the SMBH. We exhibit how the gyroscope precession is built into this dynamics, and find the secular Hamiltonian by both averaging over the inner and outer orbits, the latter being the orbit of the BBH around the SMBH. We study the long-time-scale dynamics, including the periastron precession and GW radiation-reaction of the binary system, finding that the strong gravity effects of the SMBH can enhance the von Zeipel-Lidov-Kozai mechanism, resulting in more cycles, higher maximum eccentricity, and thereby a shorter merger time, particularly when the binary is close to, or at, the innermost stable orbit of the SMBH. We end with an analysis of the peak frequency of the GW emission from the binary system, highlighting possible observable signatures in the LISA and ET frequency bands.

Even if globally neutral, in various scenarios compact objects can have a nonvanishing dipole moment. Examples include neutron stars with magnetic dipoles, black-hole microstates in the string-theory fuzzball scenario, and classical black holes in modified theories of gravity with spin-induced scalarization or Lorentz-violating terms. A fundamental dipole moment would give rise to rich phenomenology, for example to intrinsic precession and extra emission channels in binary systems. We show that extreme mass-ratio inspirals (EMRIs) detectable by future gravitational-wave interferometers allow us to study a fundamental dipole on the secondary object in a model-agnostic fashion. By developing a general model for a fundamental scalar dipole, we compute the extra flux associated with it. This effect is suppressed by the square of the mass ratio relative to the case of fundamental charges, making its detection with EMRIs very challenging for the typical dipole moments predicted in various models. On the other hand, for the same reason the impact of an extra dipole for constraints on extra fundamental charges is likely negligible, making the latter constraints more robust.

We develop a formalism to model neutrino evolution encompassing both flavor and particle-antiparticle mixings and decohering collisions. Our results include a quantum kinetic equation (a set of coupled scalar equations) for the generalized neutrino density matrix, valid for arbitrary neutrino masses and kinematics, and a comprehensive set of Feynman rules to compute collision integrals for coherently evolving states. We expose a novel shell structure describing the phase space of mixing neutrinos and show how the prior information on the system can enter into the theory and modify the neutrino flavor evolution. Potential applications of our results include modelling neutrino distributions in hot and dense environments and studies of neutrino mixing effects in colliders and in the early Universe.

Quintessence models have been widely examined in the context of scalar-Gauss-Bonnet gravity, a subclass of Horndeski's theory, and were proposed as viable candidates for Dark Energy. However, the relatively recent observational constraints on the speed of gravitational waves $c_{\textrm{GW}}$ have resulted in many of those models being ruled out because they predict $c_{\textrm{GW}} \neq c$ generally. While these were formulated in the metric formalism of gravity, it was found later that some Horndeski models could be rescued in the Palatini formalism, where the connection is independent of the metric and the underlying geometry no longer corresponds to the pseudo-Riemannian one. Motivated by this and the relation between scalar-Gauss-Bonnet gravity and Horndeski's theory, we put forward a new quintessence model with the scalar-Gauss-Bonnet action but in Weyl geometry. We find the fixed points of the dynamical system under some assumptions and determine their stability via linear analysis. Although the past evolution of the Universe as we know it is correctly reproduced, the constraints on $c_{\textrm{GW}}$ are shown to be grossly violated for the coupling function under consideration. The case of $c_{\textrm{GW}} = c$ is regarded also, but no evolution consistent with other cosmological observations is obtained.

The early and precise localization of gravitational waves (GWs) is pivotal in detecting their electromagnetic (EM) counterparts, especially for binary neutron stars (BNS) and neutron star-black hole binaries (NSBH). In this paper, we pioneer the exploration of utilizing the higher harmonic modes induced by the eccentricity of compact binaries to localize GWs with ground-based detectors even before the dominant quadrupole mode enters the detector band. Our theoretical analysis marks a first in proposing a strategy for gaining the earliest possible warning and maximizing preparation time for observing pre- and/or post-merger EM counterparts. We simulate three typical binaries from GWTC-3 with eccentricities ranging from 0.05 to 0.4. Our results reveal that the third-generation (3G) detectors (low frequency cut-off $f_0=5$ Hz) can accumulate sufficient signal-to-noise ratios through higher modes before the onset of quadrupole mode entry into the band. Notably, relying solely on the higher modes, the 3G detector network ET+2CE achieves an average localization on the order of $1-10^2~\rm deg^2$ around 1-1.8 hours before the merger of a GW170817-like BNS, and $10-10^3~\rm deg^2$ approximately 18-30 minutes prior to the merger of a GW200115-like NSBH. Moreover, in the near face-on orientations which are generally more favorable for EM counterpart detection, the localization can be further improved.

We derive a robust bound on the QCD axion by confronting momentum-dependent Boltzmann equations against up-to-date measurements of the Cosmic Microwave Background, including ground-based telescopes, and abundances from Big Bang Nucleosynthesis. We compare the axion phase-space distribution obtained from unitarized next-to-leading order chiral perturbation theory with the phenomenological one based on pion-scattering data. Our bound is $\sim$30\% stronger than what previously found: $m_{a} \leq \, 0.16 $ eV at 95\% probability. We present forecasts using dedicated likelihoods for future cosmological surveys and the sphaleron rate from unquenched lattice QCD.

This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.

High-dispersion (channel width 0.015 km s^-1) laboratory spectroscopy of the torsion-rotation lines J_2 - J_1 (J = 2 - 6) in the ground torsional state (vt = 0) of the E-type methanol demonstrates multicomponent hyperfine splitting patterns at 25 GHz. The observed patterns are compared with simulations of CH3OH emission lines based on ab initio quantum-mechanical models. A substantial disparity between the laboratory and simulated patterns is revealed. The observed morphology of the line shapes is not reproduced in the model profiles. The found inconsistency requires further refinement of the current quantum-mechanical models to fit the observed hyperfine splitting patterns at 25 GHz.

We present a deep neural network which predicts the stability of isotropic steady states of the asymptotically flat, spherically symmetric Einstein-Vlasov system in Schwarzschild coordinates. The network takes as input the energy profile and the redshift of the steady state. Its architecture consists of a U-Net with a dense bridge. The network was trained on more than ten thousand steady states using an active learning scheme and has high accuracy on test data. As first applications, we analyze the validity of physical hypotheses regarding the stability of the steady states.

Scalar dark matter (DM), and axions in particular, have an irreducible abundance of particles produced by freeze-in due to portal interactions with the Standard Model plasma in the early Universe. In addition, vacuum misalignment and other mechanisms can lead to the presence of a cold, oscillating condensate. Therefore, generically, the evolution of the DM in both forms, condensate and particles, needs to be studied simultaneously. In non-equilibrium quantum field theory, the condensate and particles are described by one- and two-point functions, respectively. The fundamental coupled equations of motion (EoMs) of these objects are non-local. To simplify the EoMs and bring them into a familiar form for relic abundance calculations, we perform a Markovianization process for a quasi-harmonically oscillating homogeneous condensate, leading to local EoMs for the particle distribution function and the envelope function of condensate oscillation. This reduces the dynamics to a pair of coupled Boltzmann equations, and we derive explicitly the form of the collision operators for all particle and condensate interactions.

A steady-state distribution is obtained that approximately yields the observed plasma density profile of the inner Van Allen radiation belt. The model assumes a collisionless, magnetized plasma with zero electric field present. The inner Van Allen belt consists of a plasma comprising high-energy protons and relativistic electrons. The particle trajectories are obtained from the collisionless Lorentz Force equation for different initial distributions. The resulting steady-state distributions obtained after particles lost to the loss cone are eliminated and are used to generate the density profile. The distribution's dependence on energy and magnetic moment is adjusted to make the density profile agree with observations. For a distribution that is a function of energy times a function of magnetic moment, the calculation leads to the desired type of density profile. The kinetic distribution and the type of density profile obtained are presented.

We present an open-source CUDA-based package that consists of a compilation of exponential integrators where the action of the matrix exponential or the $\varphi_l$ functions on a vector is approximated using the method of polynomial interpolation at Leja points. Using a couple of test examples on an NVIDIA A100 GPU, we show that one can achieve significant speedups using CUDA over the corresponding CPU code. LeXInt, written in a modular format, facilitates easy integration into any existing software package, and can be used for temporal integration of any differential equation.

Understanding the orbits of spinning bodies in curved spacetime is important for modeling binary black hole systems with small mass ratios. At zeroth order in mass ratio, the smaller body moves on a geodesic. Post-geodesic effects are needed to model the system accurately. One very important post-geodesic effect is the gravitational self-force, which describes the small body's interaction with its own contribution to a binary's spacetime. Another post-geodesic effect, the spin-curvature force, is due to the smaller body's spin coupling to spacetime curvature. In this paper, we combine the leading orbit-averaged backreaction of point-particle gravitational-wave emission with the spin-curvature force to construct the worldline and gravitational waveform for a spinning body spiraling into a Kerr black hole. We use an osculating geodesic integrator, which treats the worldline as evolution through a sequence of geodesic orbits, as well as near-identity transformations, which eliminate dependence on orbital phases, allowing for fast computation of inspirals. The resulting inspirals and waveforms include all critical dynamical effects which govern such systems (orbit and precession frequencies, inspiral, strong-field gravitational-wave amplitudes), and as such form an effective first model for the inspiral of spinning bodies into Kerr black holes. We emphasize that our present calculation is not self consistent, since we neglect effects which enter at the same order as effects we include. However, our analysis demonstrates that the impact of spin-curvature forces can be incorporated into EMRI waveform tools with relative ease. The calculation is sufficiently modular that it should not be difficult to include neglected post-geodesic effects as efficient tools for computing them become available. (Abridged)

Long-baseline atom interferometers, such as the one to be built by the AION collaboration, require ultra-cold atomic clouds. These are produced by trapping the atoms in Magneto-Optical Traps (MOTs) using high-power, narrow-linewidth lasers. We report on the laser and optical master-slave injection locked system used to address the 1S0 - 3P1 strontium transition at 689 nm, and on the trapping of strontium atoms in a narrowband MOT. We demonstrate the quality of the injection through the characterisation of the injection lock using a novel, easy-to-assemble method which uses a double pass acousto-optic modulator (AOM) to generate and detect a heterodyne beatnote. The reported system is used to produce an atomic cloud at a temperature of 812 +/- 43 nK in a narrowband red MOT.

An explanation of the nature of dark energy has been treated in extra dimensions within the scheme of string theory. One of the most successful models is inspired by the Dvali-Gabadadze-Porrati (DGP) model, in which the universe is a 4-dimensional brane embedded in a 5-dimensional Minkowski space-time. In this landscape, the study of the evolution of the normal branch has led us to different kinds of dark energy, where the most simple case is the cosmological constant $\Lambda$. Moreover, other viable cosmological solutions are related to agegraphic dark energy, which allows a late cosmic acceleration within an interacting mechanism. To explore the viability of these solutions and a possible gravitational leakage, in this paper, we present constraints on such models using recent standard sirens forecasting in addition to local observables such as Supernovae Type Ia. Our results show that the value associated with the species of quantum fields $n$ in these models is strongly restricted for supernovae observations to $n=20$, and for GW standard sirens mock data prefers a value of $n=1$.

We outline a new production mechanism for dark matter that we dub "recycling": dark sector particles are kinematically trapped in the false vacuum during a dark phase transition; the false pockets collapse into primordial black holes (PBHs), which ultimately evaporate before Big Bang Nucleosynthesis (BBN) to reproduce the dark sector particles. The requirement that all PBHs evaporate prior to BBN necessitates high scale phase transitions and hence high scale masses for the dark sector particles in the true vacuum. Our mechanism is therefore particularly suited for the production of ultra heavy dark matter (UHDM) with masses above $\sim 10^{12}\,{\rm GeV}$. The correct relic density of UHDM is obtained because of the exponential suppression of the false pocket number density. Recycled UHDM has several novel features: the dark sector today consists of multiple decoupled species that were once in thermal equilibrium and the PBH formation stage has extended mass functions whose shape can be controlled by IR operators coupling the dark and visible sectors.