Papers for Wednesday, May 10 2023

The potential energy from a time-dependent scalar field provides a possible explanation for the observed cosmic acceleration. In this paper, we investigate how the redshift vs brightness data from the recent Pantheon+ survey of type Ia supernovae constrain the possible evolution of a single scalar field for the period of time (roughly half the age of the universe) over which supernova data are available. Taking a linear approximation to the potential, we find that models providing a good fit to the data typically have a decreasing potential energy at present (accounting for over 99% of the allowed parameter space) with a significant variation in scalar potential ($\langle {\rm Range}(V)/V_0 \rangle \approx 0.97$) over the period of time corresponding to the available data ($z < 2.3$). Including quadratic terms in the potential, the data can be fit well for a wide range of possible potentials including those with positive or negative $V_2$ of large magnitude, and models where the universe has already stopped accelerating. We describe a few degeneracies and approximate degeneracies in the model that help explain the somewhat surprising range of allowed potentials.

We introduce a new imaging analysis technique to study the spatial distribution of the X-ray emission from the hot bubble of planetary nebula BD+30 3639. Hot bubble emission is typically photon-starved, thus limiting the methods for spatial-spectral analysis, however, this new technique uses the statistics of photon energies across the nebula to identify spatial variations. Using the median energy value of the X-ray photons, we identified a rise in median energy values towards the projected edge of the nebula, which we refer to as radial spectral hardening. We explored the origin of this radial spectral hardening with X-ray spectral analysis of distinct regions of high- and low-median energy values. Given that the hot bubble is embedded within a young, dense, planetary nebula, we argue that the radial spectral hardening is due to an increased column density at the projected nebular edge. Median energy imaging provides a promising new methodology for exploring the spatial variations in faint extended X-ray sources.

We investigate the impact of field-to-field variation, deriving from cosmic variance, in measured Lyman-$\alpha$ emitter (LAE) luminosity functions (LFs) and this variation's impact on inferences of the neutral fraction of the intergalactic medium (IGM) during reionization. We post-process a z=7 IGM simulation to populate the dark matter halos with LAEs. These LAEs have realistic UV magnitudes, Ly$\alpha$ fluxes, and Ly$\alpha$ line profiles. We calculate the attenuation of Ly$\alpha$ emission in universes with varying IGM neutral fraction, $\bar{\rm{x}}_{\rm{HI}}$. In a $\bar{\rm{x}}_{\rm{HI}}=0.3$ simulation, we perform 100 realizations of a mock 2 square degree survey with a redshift window $\Delta z = 0.5$ and flux limit $\rm{f}_{Ly\alpha}>1\times10^{-17}\:\rm{ergs}\:\: \rm{s}^{-1} \: \rm{cm}^{-2}$; such a survey is typical in depth and volume of the largest LAE surveys conducted today. For each realization, we compute the LAE LF and use it to recover the input $\bar{\rm{x}}_{\rm{HI}}$. Comparing the inferred values of $\bar{\rm{x}}_{\rm{HI}}$ across the ensemble of the surveys, we find that cosmic variance, deriving from large-scale structure and variation in the neutral gas along the sightline, imposes a floor in the uncertainty of $\Delta \bar{\rm{x}}_{\rm{HI}} \sim 0.2$ when $\bar{\rm{x}}_{\rm{HI}}$ $=0.3$. We explore mitigation strategies to decrease this uncertainty, such as increasing the volume, decreasing the flux limit, or probing the volume with many independent fields. Increasing the area and/or depth of the survey does not mitigate the uncertainty, but composing a survey with many independent fields is effective. This finding highlights the best strategy for LAE surveys aiming at constraining $\bar{\rm{x}}_{\rm{HI}}$ of the universe during reionization.

Quiescent galaxies having more compact morphologies than star-forming galaxies has been a consistent result in the field of galaxy evolution. What is not clear is at what point this divergence happens, i.e. when do quiescent galaxies become compact, and how big of a role does the progenitor effect play in this result? Here we aim to model the morphological and star-formation histories of high redshift (0.8 $<$ z $<$ 1.65) massive galaxies (log(M/M$\odot$) $>$ 10.2) with stellar population fits using HST/WFC3 G102 and G141 grism spectra plus photometry from the CLEAR (CANDELS Lyman-alpha Emission at Reionization) survey, constraining the star-formation histories for a sample of $\sim$ 400 massive galaxies using flexible star-formation histories. We develop a novel approach to classifying galaxies by their formation activity in a way that highlights the green valley population, by modeling the specific star-formation rate distributions as a function of redshift and deriving the probability that a galaxy is quiescent (PQ). Using PQ and our flexible star-formation histories we outline the evolutionary paths of our galaxies in relation to stellar mass, Sersic index, $R_{eff}$, and stellar mass surface density. We find that galaxies show no appreciable stellar mass growth after entering the green valley (a net decrease of 4$\%$) while their stellar mass surface densities increase by $\sim$ 0.25 dex. Therefore galaxies are becoming compact during the green valley and this is due to increases in Sersic index and decreases in $R_{eff}$.

An ionization front (I-front) that propagates through an inhomogeneous medium is slowed down by self-shielding and recombinations. We perform cosmological radiation hydrodynamics simulations of the I-front propagation during the epoch of cosmic reionization. The simulations resolve gas in minihalos (halo mass $10^4\lesssim M_h[{\rm M}_\odot]\lesssim 10^8)$ that could dominate recombinations, in a computational volume that is large enough to sample the abundance of such halos. The numerical resolution is sufficient (gas particle mass $\sim 20{\rm M}_\odot$, spatial resolution $< 0.1\;{\rm ckpc}$) to allow accurate modelling of the hydrodynamic response of gas to photo-heating. We quantify the photo-evaporation time of minihalos as a function of $M_h$ and its dependence on the photo-ionization rate, $\Gamma_{-12}$, and the redshift of reionization, $z_i$. The recombination rate can be enhanced over that of a uniform medium by a factor $\sim 10-20$ early on. The peak value increases with $\Gamma_{-12}$ and decreases with $z_i$, due to the enhanced contribution from minihalos. The clumping factor, $c_r$, decreases to a factor of a few at $\sim 100\;{\rm Myr}$ after the passage of the I-front when the minihalos have been photo-evaporated; this asymptotic value depends only weakly on $\Gamma_{-12}$. Recombinations increase the required number of photons per baryon to reionize the Universe by 20-100 per cent, with the higher value occurring when $\Gamma_{-12}$ is high and $z_i$ is low. We complement the numerical simulations with simple analytical models for the evaporation rate and the inverse Str\"omgren layer. The study also demonstrates the proficiency and potential of SPHM1RT to address astrophysical problems in high-resolution cosmological simulations.

The distribution of moving groups in the solar neighborhood has been used to constrain dynamical properties of the Milky Way for decades. Unfortunately, the unique bimodality between the main mode (Hyades, Pleiades, Coma Berenices, and Sirius) and Hercules can be explained by two different bar models -- via the outer Lindblad resonance of a short, fast bar, or via the corotation resonance of a long, slow bar. In this work, we break this degeneracy by using Gaia DR3 to explore the variation of Hercules across Galactic azimuth. We find that Hercules increases in $V_\phi$ and becomes stronger as we move towards the minor axis of the bar, and decreases in $V_\phi$ and becomes weaker as we move towards the major axis of the bar. This is in direct agreement with theoretical predictions of a long, slow bar model in which Hercules is formed by the corotation resonance with stars orbiting the bar's L4/L5 Lagrange points.

This short document illustrates QLUSTER: a toy model for populations of binary black holes in dense astrophysical environments. QLUSTER is a simple tool to investigate the occurrence and properties of hierarchical black-hole mergers detectable by gravitational-wave interferometers. QLUSTER is not meant to rival the complexity of state-of-the-art population synthesis and N-body codes but rather provide a fast, approximate, and easy-to-interpret framework to investigate some of the key ingredients of the problem. These include the binary pairing probability, the escape speed of the host environment, and the merger generation. We also introduce the "hierarchical-merger efficiency" -- an estimator that quantifies the relevance of hierarchical black-hole mergers in a given astrophysical environment.

We present results from the first molecular line survey to search for the fundamental complex organic molecule, methanol (CH$_{3}$OH), in 14 Class 0/I proto-brown dwarfs (proto-BDs). IRAM 30-m observations over the frequency range of 92-116 GHz and 213-280 GHz have revealed emission in 14 CH$_{3}$OH transition lines, at upper state energy level, E$_{upper}\sim$7-49 K, and critical densities, $n_{crit}$ of 10$^{5}$ to 10$^{9}$ cm$^{-3}$. The most commonly detected lines are at E$_{upper} <$ 20 K, while 11 proto-BDs also show emission in the higher excitation lines at E$_{upper}\sim$21-49 K and $n_{crit}\sim$10$^{5}$ to 10$^{8}$ cm$^{-3}$. In comparison with the brown dwarf formation models, the high excitation lines likely probe the warm ($\sim$25-50 K) corino region at $\sim$10-50 au in the proto-BDs, while the low-excitation lines trace the cold ($<$ 20 K) gas at $\sim$50-150 au. The column density for the cold component is an order of magnitude higher than the warm component. The CH$_{3}$OH ortho-to-para ratios range between $\sim$0.3-2.3. The volume-averaged CH$_{3}$OH column densities show a rise with decreasing bolometric luminosity among the proto-BDs, with the median column density higher by a factor of $\sim$3 compared to low-mass protostars. Emission in high-excitation (E$_{upper}>$ 25 K) CH$_{3}$OH lines together with the model predictions suggest that a warm corino is present in $\sim$78\% of the proto-BDs in our sample. The remaining show evidence of only the cold component, possibly due to the absence of a strong, high-velocity jet that can stir up the warm gas around it.

Centers of galaxies host both a supermassive black hole and a dense stellar cluster. Such an environment should lead to stellar collisions, possibly at very high velocities so that the total energy involved is of the same order as supernovae explosions. We present a simplified numerical analysis of the destructive stellar collision rate in a cluster similar to that of the Milky Way. The analysis includes an effective average two-body relaxation Monte-Carlo scheme and general relativistic effects, as used by Sari and Fragione (2019), to which we added explicit tracking of local probabilities for stellar collisions. We also consider stars which are injected into the stellar cluster after being disrupted from a binary system by the supermassive black hole. Such stars are captured in the vicinity of the black hole and enhance the expected collision rate. In our results we examine the rate and energetic distribution function of high velocity stellar collisions, and compare them self-consistently with the other destructive processes which occur in the galactic center, namely tidal disruptions and extreme mass ratio inspirals.

The work is devoted to the analysis of the influence of the galactic bar on the orbital motion of globular clusters in the central region of the Galaxy. For this task, 45 globular clusters were selected, 34 of which belong to the bulge/bar and 11 to the disk. The most accurate astrometric data from the Gaia satellite (Vasiliev and Baumgardt, 2021), as well as new refined average distances (Baumgardt and Vasiliev, 2021), were used to form the 6D-phase space required for orbit integration. The orbits of globular clusters are obtained both in an axisymmetric potential and in a potential including a bar. In this case, the mass, rotation velocity, shape and scale length of the bar were varied. A comparison is made of such orbital parameters as apocentric and pericentric distances, eccentricity and maximum distance from the galactic plane. It is shown that the mass of the bar exerts the greatest influence on the orbital motion, which is expressed mainly in an increase in both the apocentric and pericentric distances in the vast majority of globular clusters. The eccentricities of the orbits in the overwhelming majority also change significantly, and there is a change both upward and downward, especially in the range of values from 0.2 to 0.8. The greatest changes in parameters are observed in globular clusters with high radial velocities and small pericentric distances. The change in orbital parameters depending on the bar rotation velocity is less pronounced. The influence of the geometric parameters of the bar is insignificant in the accepted range of their changes. Several examples show that globular clusters in the bulge are more affected by the bar than those belonging to the disk.

A growing number of supernovae (SNe) are now known to exhibit evidence for significant interaction with a dense, pre-existing, circumstellar medium (CSM). SNe Ibn comprise one such class that can be characterised by both rapidly evolving light curves and persistent narrow He I lines. The origin of such a dense CSM in these systems remains a pressing question, specifically concerning the progenitor system and mass-loss mechanism. In this paper, we present multi-wavelength data of the Type Ibn SN 2020nxt, including $HST$/STIS ultraviolet spectra. We fit the data with recently updated CMFGEN models designed to handle configurations for SNe Ibn. The UV coverage yields strong constraints on the energetics and, when combined with the CMFGEN models, offer new insight on potential progenitor systems. We find the most successful model is a $\lesssim4 {\rm M}_\odot$ helium star that lost its $\sim 1\,{\rm M}_\odot$ He-rich envelope in the years preceding core collapse. We also consider viable alternatives, such as a He white dwarf merger. Ultimately, we conclude at least some SNe Ibn do not arise from single, massive ($>30 {\rm M}_\odot$) Wolf-Rayet-like stars.

In this study we combine asteroseismic, spectroscopic and kinematic information to perform a detailed analysis of a sample of 16 stars from the Kepler field. Our selection focuses on stars that appear to contradict Galactic chemical evolution models: young and $\alpha$-rich, old and metal-rich, as well as other targets with unclear classification in past surveys. Kinematics are derived from Gaia DR3 parallaxes and proper motions, and high-resolution spectra from HIRES/Keck are used to calculate chemical abundances for over 20 elements. This information is used to perform careful checks on asteroseismic masses and ages derived via grid-based modelling. Among the seven stars previously classified as young and $\alpha$-rich, only one seems to be an unambiguously older object masking its true age. We confirm the existence of two very old ($\geq$11 Gyr), super metal rich ($\geq$0.1 dex) giants. These two stars have regular thin disc chemistry and in-plane solar circle orbits which fit well in the picture of radial migration via the churning mechanism. The alternative explanation that these stars have younger ages would require mass-loss rates which strongly increases with increasing metallicity. Finally, we suggest further investigations to explore the suitability of Zn as a chemical clock in red giants.

Accreting black holes commonly exhibit hard X-ray emission, originating from a region of hot plasma near the central engine referred to as the corona. The origin and geometry of the corona are poorly understood, and models invoking either inflowing or outflowing material (or both) can successfully explain only parts of the observed phenomenology. In particular, recent works indicate that the time-averaged and variability property might originate in different regions of the corona. In this paper we present a model designed to move beyond the lamp post paradigm, with the goal of accounting for the vertical extent of the corona. In particular, we highlight the impact of including self consistently a second lamp post, mimicking for example an extended jet base. We fully include the effect that the second source has on the time-dependent disk ionization, reflection spectrum, and reverberation lags. We also present an application of this new model to NICER observations of the X-ray binary MAXI J1820+070 near its hard-to-soft state transition. We demonstrate that in these observations, a vertically extended corona can capture both spectral and timing properties, while a single lamp post model can not. In this scenario, the illumination responsible for the time-averaged spectrum originates close to the black hole, while the variability is likely associated with the ballistic jet.

The final phase of the reionization process can be probed by rest-frame UV absorption spectra of quasars at z>6, shedding light on the properties of the diffuse intergalactic medium within the first Gyr of the Universe. The ESO Large Programme "XQR-30: the ultimate XSHOOTER legacy survey of quasars at z~5.8-6.6" dedicated ~250 hours of observations at the VLT to create a homogeneous and high-quality sample of spectra of 30 luminous quasars at z~6, covering the rest wavelength range from the Lyman limit to beyond the MgII emission. Twelve quasar spectra of similar quality from the XSHOOTER archive were added to form the enlarged XQR-30 sample, corresponding to a total of ~350 hours of on-source exposure time. The median effective resolving power of the 42 spectra is R~11400 and 9800 in the VIS and NIR arm, respectively. The signal-to-noise ratio per 10 km/s pixel ranges from ~11 to 114 at $\lambda \simeq 1285$ \AA rest frame, with a median value of ~29. We describe the observations, data reduction and analysis of the spectra, together with some first results based on the E-XQR-30 sample. New photometry in the H and K bands are provided for the XQR-30 quasars, together with composite spectra whose characteristics reflect the large absolute magnitudes of the sample. The composite and the reduced spectra are released to the community through a public repository, and will enable a range of studies addressing outstanding questions regarding the first Gyr of the Universe.

We explore terrestrial planet formation with a focus on the supply of solid-state organics as the main source of volatile carbon. For the water-poor Earth, the water ice line, or ice sublimation front, within the planet-forming disk has long been a key focal point. We posit that the soot line, the location where solid-state organics are irreversibly destroyed, is also a key location within the disk. The soot line is closer to the host star than the water snowline and overlaps with the location of the majority of detected exoplanets. In this work, we explore the ultimate atmospheric composition of a body that receives a major portion of its materials from the zone between the soot line and water ice line. We model a silicate-rich world with 0.1% and 1% carbon by mass with variable water content. We show that as a result of geochemical equilibrium, the mantle of these planets would be rich in reduced carbon but have relatively low water (hydrogen) content. Outgassing would naturally yield the ingredients for haze production when exposed to stellar UV photons in the upper atmosphere. Obscuring atmospheric hazes appear common in the exoplanetary inventory based on the presence of often featureless transmission spectra (Kreidberg et al. 2014, Knutson et al. 2014, Libby-Roberts et al. 2020). Such hazes may be powered by the high volatile content of the underlying silicate-dominated mantle. Although this type of planet has no solar system counterpart, it should be common in the galaxy with potential impact on habitability.

The study of molecules and their chemistry in star-forming regions is fundamental to understand the physical process occurring in such regions. The HCN and HNC J=1-0 emissions were used to derive their integrated line intensities (I), to probe a relation recently appeared in the literature between the kinetic temperatures (T$_{K}$) and the isomeric (I) ratio, and to obtain the isomers abundances (X) in 55 high-mass star-forming regions. These last ones are classified, according to the evolutive stage, as infrared dark clouds, high-mass protostellar objects, hot molecular cores, and ultracompact HII regions. It is inferred that the T$_{K}$ obtained from the isomeric integrated intensity ratio (I$^{HCN/HNC}$) are underestimated, and hence we suggest that this relation cannot be employed as an universal thermometer in the interstellar medium. The isomers abundances show a behavior that can be explained from the chemistry occurring as the temperature and the UV radiation increase according to the evolutive stage. We found that the abundance ratio (X$^{HCN/HNC}$) hardly could be used as a chemical clock, and we suggest that it can be approximated by I$^{HCN/HNC}$. This work is part of an on-going study of multiple molecules that stand in the sample of analyzed regions which intends to contribute in the chemical knowledge of high-mass star formation.

Of the over 5000 exoplanets that have been detected, only about a dozen have ever been directly imaged. Earth-like exoplanets are on the order of 10 billion times fainter than their host star in visible and near-infrared, requiring a coronagraph instrument to block primary starlight and allow for the imaging of nearby orbiting planets. In the pursuit of direct imaging of exoplanets, scalar vortex coronagraphs (SVCs) are an attractive alternative to vector vortex coronagraphs (VVCs). VVCs have demonstrated 2e-9 raw contrast in broadband light but have several limitations due to their polarization properties. SVCs imprint the same phase ramp as VVCs on the incoming light and do not require polarization splitting, but they are inherently chromatic. Discretized phase ramp patterns such as a wrapped staircase help reduce SVC chromaticity and simulations show it outperforms a chromatic classical vortex in broadband light. We designed, fabricated, and tested a wrapped staircase SVC, and here we present the broadband characterization on the high contrast spectroscopy testbed. We also performed wavefront correction on the in-air coronagraph testbed at NASA's Jet Propulsion Laboratory and achieved an average raw contrasts of 3.2e-8 in monochromatic light and 2.2e-7 across a 10% bandwidth.

The hyperfine 21-cm transition of neutral hydrogen from the early Universe ($z>5$) is a sensitive probe of the formation and evolution of the first luminous sources. Using the Fisher matrix formalism we explore the complex and degenerate high-dimensional parameter space associated with the high-$z$ sources of this era and forecast quantitative constraints from a future 21-cm power spectrum (21-cm PS) detection. This is achieved using MERAXES, a coupled semi-analytic galaxy formation model and reionisation simulation, applied to an $N$-body halo merger tree with a statistically complete population of all atomically cooled galaxies out to $z\sim20$. Our mock observation assumes a 21-cm detection spanning $z \in [5, 24]$ from a 1000 h mock observation with the forthcoming Square Kilometre Array and is calibrated with respect to ultraviolet luminosity functions (UV LFs) at $z\in[5, 10]$, the optical depth of CMB photons to Thompson scattering from Planck, and various constraints on the IGM neutral fraction at $z > 5$. In this work, we focus on the X-ray luminosity, ionising UV photon escape fraction, star formation and supernova feedback of the first galaxies. We demonstrate that it is possible to recover 5 of the 8 parameters describing these properties with better than $50$ per cent precision using just the 21-cm PS. By combining with UV LFs, we are able to improve our forecast, with 5 of the 8 parameters constrained to better than 10 per cent (and all below 50 per cent).

Although silver-based telescope mirrors excel over other materials such as gold and aluminum in the visible-infrared spectral range, they require robust protective coatings to overcome their inherent low durability. Our research shows that a single-layer of aluminum oxide (AlOx) deposited through thermal atomic layer deposition (ALD) using trimethylaluminum (TMA) and water (H2O) at low temperatures (~60{\deg}C) serves as an acceptable protective coating without adversely impacting the optical performance of the mirrors. While silver-based mirrors protected with a single-layer of AlOx perform decently in the field, in environmental tests under high-humidity at high-temperature conditions that accelerate underlying failure mechanisms, they degrade quickly, suggesting that there is room for improvement. This paper describes a study that compares the performance and endurance of two sets of silver-based mirrors protected by a single-layer of AlOx prepared by thermal ALD with two types of oxygen precursors: H2O and pure ozone (PO). The study shows that while the two types of samples, regardless of their oxygen precursors, initially have comparable spectral reflectance, the reflectance of the samples with AlOx protective coatings prepared with PO remain nearly constant 1.6 times longer than those with AlOx protective coatings prepared with H2O in the environmental test, suggesting promising characteristics of AlOx protective coatings prepared with PO.

We report the first search result for the flux of astrophysical electron antineutrinos for energies O(10) MeV in the gadolinium-loaded Super-Kamiokande (SK) detector. In June 2020, gadolinium was introduced to the ultra-pure water of the SK detector in order to detect neutrons more efficiently. In this new experimental phase, SK-Gd, we can search for electron antineutrinos via inverse beta decay with efficient background rejection and higher signal efficiency thanks to the high efficiency of the neutron tagging technique. In this paper, we report the result for the initial stage of SK-Gd with a $22.5\times552$ $\rm kton\cdot day$ exposure at 0.01% Gd mass concentration. No significant excess over the expected background in the observed events is found for the neutrino energies below 31.3 MeV. Thus, the flux upper limits are placed at the 90% confidence level. The limits and sensitivities are already comparable with the previous SK result with pure-water ($22.5 \times 2970 \rm kton\cdot day$) owing to the enhanced neutron tagging.

GRB 221009A has posed a significant challenge to our current understanding of the mechanisms that produce TeV photons in gamma-ray bursts (GRB). On one hand, the Klein-Nishina (KN) effect of the inverse Compton scattering leads to less efficient energy losses of high-energy electrons. In the other hand, at a redshift of 0.151, the TeV spectrum of GRB 221009A undergoes significant absorption by the Extragalactic Background Light (EBL). Therefore, the observation of 18-TeV and 250-TeV photons in this event implies the presence of enormous photon fluxes at the source, which cannot be easily generated by the Synchrotron Self-Compton mechanism in external shocks. As an alternative, some authors have suggested the possibility of converting the TeV-photons into Axion-like particles (ALPs) at the host galaxy, in order to avoid the effects of EBL absorption, and then reconverting them into photons within the Milky Way. While this solution relaxes the requirement of very-high photon fluxes, the KN effect still poses a challenge. Previously, we have showed that the injections of ALPs could explain the observation of 18-TeV photons. Here, we include the energy dependence of the survival probability to determine the spectral conditions that would be required for the injection of such ALPs, limit the ALP's candidate region, and discuss the implications in the maximum particle rate for different light-curve assumptions.

Green Pea galaxies are compact galaxies with high star formation rates. However, limited samples of Green Pea galaxies have HI 21 cm measurements. Whether the HI gas fraction f_{HI} = M_{HI}/M_{*} of Green Pea galaxies follows the existing scaling relations between the f_{HI} and NUV-r color or linear combinations of color and other physical quantities needs checking. Using archival data of HI 21cm observations, we investigate the scaling relation of the NUV-r color with the M_{HI}/M_{*} of 38 Green Pea galaxies, including 17 detections and 21 non-detections. The HI to stellar mass ratios (f_{HI}) of Green Pea galaxies deviate from the polynomial form, where a higher HI gas fraction is predicted given the current NUV-r color, even with the emission lines removed. The blue sources (NUV-r<1) from the comparison sample (ALFALFA-SDSS) follow a similar trend. The HI gas fraction scaling relations with linear combination forms of -0.34(NUV-r) - 0.64 log(mu_{*,z}) + 5.94 and -0.77 log mu_{*,i} + 0.26 log SFR/M_{*}+8.53, better predict the HI gas fraction of the Green Pea galaxies. In order to obtain accurate linear combined forms, higher-resolution photometry from space-based telescopes is needed.

The Atacama Large Millimetre/submillimetre Array (ALMA) is the world's most advanced radio interferometric facility, producing science data with an average rate of about 1 TB per day. After a process of calibration, imaging and quality assurance, the scientific data are stored in the ALMA Science Archive (ASA), along with the corresponding raw data, making the ASA an invaluable resource for original astronomical research. Due to their complexity, each ALMA data set has the potential for scientific results that go well beyond the ideas behind the original proposal that led to each observation. For this reason, the European ALMA Regional Centre initiated the High-Level Data Products initiative to develop science-oriented data products derived from data sets publicly available in the ASA, that go beyond the formal ALMA deliverables. The first instance of this initiative is the creation of a catalogue of submillimetre (submm) detections of Sloan Digital Sky Survey (SDSS) quasars from the SDSS Data Release 14 that lie in the aggregate ALMA footprint observed since ALMA Cycle 0. The ALMA fluxes are extracted in an automatic fashion, using the ALMA Data Mining Toolkit. All extractions above a signal-to-noise cut of 3.5 are considered, they have been visually inspected and the reliable detections are presented in a catalogue of 376 entries, corresponding to 275 unique quasars. Interesting targets found in the process, i.e. lensed or jetted quasars as well as quasars with nearby submm counterparts are highlighted, to facilitate further studies or potential follow up observations.

We present a series of high-resolution simulations generated with the moving-mesh code AREPO to model the merger of a $1.1 \, \mathrm{M_\odot}$ carbon-oxygen primary white dwarf with an outer helium layer and a $0.35\,\mathrm{M_\odot}$ secondary helium white dwarf. Our simulations lead to detonations that are consistent with the edge-lit scenario, where a helium detonation is ignited at the base of the helium layer of the primary WD, which triggers an off-centre carbon detonation. This produces an asymmetric ejecta pattern and differences in line-of-sight observables (e.g. mean atomic weight). The ejecta that are flung into space are dominated by $^{56}\mathrm{Ni}$, $^{4}\mathrm{He}$, $^{28}\mathrm{Si}$, and $^{32}\mathrm{S}$. Our simulations result in a surviving degenerate companion of mass $0.22-0.25$ $\mathrm{M_\odot}$ moving at $>1\,700$ $\mathrm{km}\,\mathrm{s}^{-1}$, consistent with the observational findings of hypervelocity WDs. The secondary's surface layers are enriched by heavy metals, with $^{56}\mathrm{Ni}$ making up approximately $0.8 \%$ of the remaining mass. We also analyse the sensitivity of the outcome on simulation parameters, including the "inspiral time", which defines a period of accelerated angular momentum loss. We find that the choice of "inspiral time" qualitatively influences the simulation result, including the survival of the secondary. We argue that the shorter inspiral cases result in qualitatively and quantitatively similar outcomes. We also investigate the sensitivity of our results on the primary's chemical profile by comparing simulations using isothermal, constant composition models with the same mass and central composition and characterised by either a bare carbon-oxygen core (no helium) or a carbon-oxygen core enveloped by a thick helium layer.

This work presents an initial on-sky performance measurement of the Single-Photon Imager for Nanosecond Astrophysics (SPINA) system, part of our Ultra-Fast Astronomy (UFA) program. We developed the SPINA system based on the position-sensitive silicon photomultiplier (PS-SiPM) detector to record both photoelectron (P.E.) temporal and spatial information. The initial on-sky testing of the SPINA system was successfully performed on UT 2022 Jul 10, on the 0.7-meter aperture Nazarbayev University Transient Telescope at the Assy-Turgen Astrophysical Observatory (NUTTelA-TAO). We measured stars with a wide range of brightness and a dark region of the sky without stars $< 18$ mag. We measured the SPINA system's spatial resolution to be $<232\mu m$ (full-width half-maximum, FWHM), limited by the unstable atmosphere. We measured the total background noise (detector dark counts and sky background) of 1914 counts per second (cps) within this resolution element. We also performed a crosstalk mapping of the detector, obtaining the crosstalk probability of $\sim0.18$ near the detector's center while reaching $\sim 50\%$ at the edges. We derived a $5\sigma$ sensitivity of $17.45$ Gaia-BP magnitude in a 1s exposure with no atmospheric extinction by comparing the received flux with Gaia-BP band data. For a $10ms$ window and a false alarm rate of once per 100 nights, we derived a transient sensitivity of 14.06 mag. For a $1\mu s$ or faster time scale, we are limited by crosstalk to a 15 P.E. detection threshold. In addition, we demonstrated that the SPINA system is capable of capturing changes in the stellar profile FWHM of $\pm1.8\%$ and $\pm5\%$ change in the stellar profile FWHM in $20ms$ and $2ms$ exposures, respectively, as well as capturing stellar light curves on the $ms$ and $\mu s$ scales.

We evaluate the prospects for radio follow-up of the double neutron stars (DNSs) in the Galactic disk that could be detected through future space-borne gravitational wave (GW) detectors. We first simulate the DNS population in the Galactic disk that is accessible to space-borne GW detectors according to the merger rate from recent LIGO results. Using the inspiraling waveform for the eccentric binary, the average number of the DNSs detectable by TianQin (TQ), LISA, and TQ+LISA are 217, 368, and 429, respectively. For the joint GW detection of TQ+LISA, the forecasted parameter estimation accuracies, based on the Fisher information matrix, for the detectable sources can reach the levels of $\Delta P_{\mathrm b}/P_{\mathrm b} \lesssim 10^{-6}$, $\Delta \Omega \lesssim 100~{\mathrm {deg}}^2$, $\Delta e/e \lesssim 0.3$, and $\Delta \dot{P}_{\mathrm b} / \dot{P}_{\mathrm b} \lesssim 0.02$. These estimation accuracies are fitted in the form of power-law function of signal-to-noise ratio. Next, we simulate the radio pulse emission from the possible pulsars in these DNSs according to pulsar beam geometry and the empirical distributions of spin period and luminosity. For the DNSs detectable by TQ+LISA, the average number of DNSs detectable by the follow-up pulsar searches using the Parkes, FAST, SKA1, and SKA are 8, 10, 43, and 87, respectively. Depending on the radio telescope, the average distances of these GW-detectable pulsar binaries vary from 1 to 7 kpc. Considering the dominant radiometer noise and phase jitter noise, the timing accuracy of these GW-detectable pulsars can be as low as 70 ${\rm ns}$ while the most probable value is about 100 $\mu {\rm s}$.

The assembly and build-up of neutral atomic hydrogen (HI) in galaxies is one of the most fundamental processes in galaxy formation and evolution. Studying this process directly in the early universe is hindered by the weakness of the hyperfine 21-cm HI line transition, impeding direct detections and measurements of the HI gas masses ($M_{\rm HI}$). Here we present a new method to infer $M_{\rm HI}$ of high-redshift galaxies using neutral, atomic oxygen as a proxy. Specifically, we derive metallicity-dependent conversion factors relating the far-infrared [OI]-$63\mu$m and [OI]-$145\mu$m emission line luminosities and $M_{\rm HI}$ in star-forming galaxies at $z\approx 2-6$ using gamma-ray bursts (GRBs) as probes. We substantiate these results by observations of galaxies at $z\approx 0$ with direct measurements of $M_{\rm HI}$ and [OI]-$63\mu$m and [OI]-$145\mu$m in addition to hydrodynamical simulations at similar epochs. We find that the [OI]$_{\rm 63\mu m}$-to-HI and [OI]$_{\rm 145\mu m}$-to-HI conversion factors universally appears to be anti-correlated with the gas-phase metallicity. The high-redshift GRB measurements further predict a mean ratio of $L_{\rm [OI]-63\mu m} / L_{\rm [OI]-145\mu m}=1.55\pm 0.12$ and reveal generally less excited [CII]. The $z \approx 0$ galaxy sample also shows systematically higher $\beta_{\rm [OI]-63\mu m}$ and $\beta_{\rm [OI]-145\mu m}$ conversion factors than the GRB sample, indicating either suppressed [OI] emission in local galaxies or more extended, diffuse HI gas reservoirs traced by the HI 21-cm. Finally, we apply these empirical calibrations to the few high-redshift detections of [OI]-$63\mu$m and [OI]-$145\mu$m line transitions from the literature and further discuss the applicability of these conversion factors to probe the HI gas content in the dense, star-forming ISM of galaxies at $z\gtrsim 6$, well into the epoch of reionization.

In this study, we carried out photometric, spectroscopic, and for the first time, polarimetric observations of the Amor-type near-Earth asteroid (2059) Baboquivari. Our findings represent the first reliable determination of Baboquivari's physical properties. We used data from a 1m-class telescope (T100) along with ALCDEF data for photometric analyses and a 1.5-m-class telescope (RTT150) for polarimetric, spectroscopic, and additional photometric observations. We obtained the synodic rotation period of Baboquivari as 129.93 +/- 2.31 hours and the standard phase function parameters H and G as 16.05 +/- 0.05, 0.22 +/- 0.02, respectively. Our colour index (V-R) measurement of 0.45 +/- 0.02 is consistent with spectroscopic observations, indicating an S (or sub-S) spectral type. Using the polarimetric and spectroscopic data, we found that the geometric albedo is 0.15 +/- 0.03, and the spectral type is Sq. Based on the estimated albedo and absolute magnitude, Baboquivari has an effective diameter of 2.12 +/- 0.21 km. Due to the scattered data in the light curve, its slow rotation and location among the NEAs suggest that Baboquivari may be a non-principal axis (NPA) rotator.

Context. In 2020, a publication presented the first-light results for 18 known ZZ Ceti stars observed by the TESS space telescope during the first survey observations of the southern ecliptic hemisphere. However, in the meantime, new measurements have become available from this field, in many cases with the new, 20s ultrashort cadence mode. Aims. We investigated the similarities and differences in the pulsational behaviour of the observed stars between the two observational seasons, and searched for new pulsation modes for asteroseismology. Methods. We performed Fourier analysis of the light curves using the standard pre-whitening process, and compared the results with frequencies obtained from the earlier data. Utilising the 2018 version of the White Dwarf Evolution Code, we also performed an asteroseismic analysis of the different stars. We searched for models with seismic distances in the vicinity of the Gaia geometric distances. Results. We detected several new possible pulsation modes of the studied pulsators. In the case of HE 0532-5605, we found a similar brightening phase to the one presented in the 2020 first-light paper, which means this phenomenon is recurring. Therefore, HE 0532-5605 appears to be a new outbursting DAV star. We also detected a lower-amplitude brightening phase in the star WD J0925+0509. However, this case has proven to be the result of the passage of a Solar System object in the foreground. We accept asteroseismic model solutions for six stars.

During cluster mergers, the intracluster gas and member galaxies undergo dynamic evolution, but at different timescales and reach different states. We collect 24 galaxy clusters in quasi-equilibrium state as indicated by the X-ray image, and calculate the cluster orientations and three kinds of dynamical parameters, i.e., the normalized centroid offset, the sphere index and the ellipticity, for these clusters from the distributions of member galaxies and also the intracluster gas. We find consistent alignments for the orientations estimated from the two components. However, the three kinds of dynamical parameters indicated by member galaxies are systematically larger than those derived from the gas component, suggesting that the gas component is more relaxed than member galaxies. Differences of dynamical features between the intracluster gas and member galaxies are independent of cluster mass and concentration. We conclude that the intracluster gas reaches the dynamic equilibrium state earlier than the almost collisionless member galaxies.

We undertake the first targeted search at 1.5 GHz for radio emission from the variable $\gamma$-ray pulsar PSR J2021$+$4026. This radio-quiet pulsar assumes one of two stable $\gamma$-ray emission states, between which it transitions on a timescale of years. These transitions, in both $\gamma$-ray flux and pulse profile shape, are accompanied by contemporaneous changes to the pulsar's spin-down rate. A number of radio pulsars are known to exhibit similar correlated variability, which in some cases involves an emission state in which the radio emission ceases to be detectable. In this paper, we perform a search for radio emission from PSR J2021$+$4026, using archival radio observations recorded when the pulsar was in each of its emission/spin-down states. Using improved techniques, we search for periodic radio emission as well as single pulse phenomena such as giant radio pulses and RRAT-like emission. Our search reveals no evidence of radio emission from PSR J2021$+$4026. We estimate that the flux density for periodic emission from PSR J2021$+$4026 does not exceed 0.2 mJy at this frequency. We also estimate single-pulse flux limits for RRAT-like bursts and giant radio pulses to be 0.3 and 100 Jy respectively. We discuss the transitioning behaviour of PSR J2021$+$4026 in the context of pulsar glitches, intermittent pulsars and the increasingly common emission-rotation correlation observed in radio pulsars.

The origin and distribution of lunar water are among the most important issues in understanding the earth-moon system. After more than half a century of laboratory research and remote detection, only hydroxyl contained minerals and lunar ice (H2O) are identified. Here we report the discovery of a hydrous mineral (NH4)MgCl3(H2O)6 in the lunar soil returned by Chang'e-5 mission, which contains 417,000 parts per million H2O. The determined structure and composition are similar to novograblenovite-a terrestrial fumarole mineral formed by reaction of hot basalt in water-rich volcanic gases, whereas the measured isotope composition delta37Cl reached 20.4 parts per thousand, a high value that only found in lunar minerals. We rule out the possibility that this hydrate originated from terrestrial contaminants or rocket exhaust through analysis of its chemical, isotopic compositions as well as the formation conditions. Our finding indicates that water can exist on some parts of the sunlit Moon in the form of hydrate compounds. Moreover, this hydrate is rich in ammonium, providing new information in understanding the origin of the Moon.

Very precise satellite photometry has revealed a large number of variable stars whose variability is caused either by surface spots or by binarity. Detailed studies of such variables provide insights into the physics of these objects. We study the nature of the periodic light variability of the white dwarf EPIC 206197016 that was observed by the K2 mission. We obtain phase-resolved medium-resolution spectroscopy of EPIC 206197016 using XSHOOTER spectrograph at VLT to understand the nature of the white dwarf variability. We use NLTE model atmospheres to determine stellar parameters at individual phases. EPIC 206197016 is a hot DA white dwarf with $T_\text{eff}=78\,$kK. The analysis of the spectra reveals periodic radial velocity variations that can result from gravitational interaction with an invisible secondary whose mass corresponds to a red dwarf. The close proximity of the two stars where the semimajor axis is about $3\,R_\odot$ results in the irradiation of the companion with temperatures more than twice as high on the illuminated side compared to the nonilluminated hemisphere. This effect can explain the observed light variations. The spectra of the white dwarf show a particular feature of the Balmer lines called the Balmer line problem, where the observed cores of the lower Balmer lines are deeper than predicted. This can be attributed to either weak pollution of hydrogen in the white dwarf atmosphere by heavy elements or to the presence of a circumstellar cloud or disk.

The reaction N(4S) + NO -> O(3P) + N2 plays a pivotal role in the conversion of atomic to molecular nitrogen in dense interstellar clouds and in the atmosphere. Here we report a joint experimental and computational investigation of the N + NO reaction with the aim of providing improved constraints on its low temperature reactivity. Thermal rates were measured over the 50 to 296 K range in a continuous supersonic flow reactor coupled with pulsed laser photolysis and laser induced fluorescence for the production and detection of N(4S) atoms, respectively. With decreasing temperature, the experimentally measured reaction rate was found to monotonously increase up to a value of (6.6 +- 1.3) x 10-11 cm3 s-1 at 50 K. To confirm this finding, quasi-classical trajectory simulations were carried out on a previously validated, full-dimensional potential energy surface (PES). However, around 50 K the computed rates decreased which required re-evaluation of the reactive PES in the long-range part due to a small spurious barrier with height 40 K in the entrance channel. By exploring different correction schemes the measured thermal rates can be adequately reproduced, displaying a clear negative temperature dependence over the entire temperature range. The possible astrochemical implications of an increased reaction rate at low temperature are also discussed.

Accretion of debris seems to be the natural mechanism to power the radiation emitted during a tidal disruption event (TDE), in which a supermassive black hole tears apart a star. However, this requires the prompt formation of a compact accretion disk. Here, using a fully relativistic global simulation for the long-term evolution of debris in a TDE with realistic initial conditions, we show that at most a tiny fraction of the bound mass enters such a disk on the timescale of observed flares. To "circularize" most of the bound mass entails an increase in the binding energy of that mass by a factor $\sim 30$; we find at most an order unity change. Our simulation suggests it would take a time scale comparable to a few tens of the characteristic mass fallback time to dissipate enough energy for "circularization". Instead, the bound debris forms an extended eccentric accretion flow with eccentricity $\simeq 0.4-0.5$ by $\sim 2$ fallback times. Although the energy dissipated in shocks in this large-scale flow is much smaller than the "circularization" energy, it matches the observed radiated energy very well. Nonetheless, the impact of shocks is not strong enough to unbind initially bound debris into an outflow.

The processes responsible for the acceleration of solar energetic particles (SEPs) are still not well understood, including whether SEP electrons and protons are accelerated by common or separate processes. Using a numerical particle transport model that includes both pitch-angle and perpendicular spatial diffusion, we simulate, amongst other quantities, the onset delay for MeV electrons and protons and compare the results to observations of SEPs from widely-separated spacecraft. Such observations have previously been interpreted, in a simple scenario assuming no perpendicular diffusion, as evidence for different electron and proton sources. We show that, by assuming a common particle source together with perpendicular diffusion, we are able to simultaneously reproduce the onset delays for both electrons and protons. We argue that this points towards a common accelerator for these particles. Moreover, a relatively broad particle source is required in the model to correctly describe the observations. This is suggestive of diffusive shock acceleration occurring at large shock structures playing a significant role in the acceleration of these SEPs.

The study of many astrophysical flows requires computational algorithms that can capture high Mach number flows, while resolving a large dynamic range in spatial and density scales. In this paper we present a novel method, RAM: Rapid Advection Algorithm on Arbitrary Meshes. RAM is a time-explicit method to solve the advection equation in problems with large bulk velocity on arbitrary computational grids. In comparison with standard up-wind algorithms, RAM enables advection with larger time steps and lower truncation errors. Our method is based on the operator splitting technique and conservative interpolation. Depending on the bulk velocity and resolution, RAM can decrease the numerical cost of hydrodynamics by more than one order of magnitude. To quantify the truncation errors and speed-up with RAM, we perform one and two-dimensional hydrodynamics tests. We find that the order of our method is given by the order of the conservative interpolation and that the effective speed up is in agreement with the relative increment in time step. RAM will be especially useful for numerical studies of disk-satellite interaction, characterized by high bulk orbital velocities, and non-trivial geometries. Our method dramatically lowers the computational cost of simulations that simultaneously resolve the global disk and well inside the Hill radius of the secondary companion.

Based on high-resolution spectra obtained with Magellan/MIKE, we present a chemo-dynamical analysis for 27 near main-sequence turnoff metal-poor stars, including 20 stars analyzed for the first time. The sample spans a range in [Fe/H] from -2.5 to -3.6, with 44% having [Fe/H] <-2.9. We derived chemical abundances for 17 elements, including strontium and barium. We derive Li abundances for the sample, which are in good agreement with the ``Spite Plateau'' value. A dozen of stars are carbon-enhanced. The lighter elements (Z<30) generally agree well with those of other low-metallicity halo stars. This broadly indicates chemically homogeneous gas at the earliest times. Of the neutron-capture elements, we only detected strontium and barium. We used the [Sr/Ba] vs. [Ba/Fe] diagram to classify metal-poor stars into five populations based on their observed ratios. We find HE0232-3755 to be a likely main r-process star, and HE2214-6127 and HE2332-3039 to be limited-r stars. CS30302-145, HE2045-5057, and CD-24 17504 plausibly originated in long-disrupted early dwarf galaxies as evidenced by their [Sr/Ba] and [Ba/Fe] ratios. We also find that the derived [Sr/H] and [Ba/H] values for CD-24 17504 are not inconsistent with the predicted yields of the s-process in massive rotating low-metallicity stars models. Further theoretical explorations will be helpful to better understand the earliest mechanisms and time scales of heavy element production for comparison with these and other observational abundance data. Finally, we investigate the orbital histories of our sample stars. Most display halo-like kinematics although three stars (CS29504-018, HE0223-2814, and HE2133-0421) appear to be disk-like in nature. This confirms the extragalactic origin for CS30302-145, HE2045-5057, and, in particular, CD-24 17504 which likely originated from a small accreted stellar system as one of the oldest stars.

We present a feasibility study for passive sounding of Uranian icy moons using Uranian Kilometric Radio (UKR) emissions in the 100 - 900 kHz band. We provide a summary description of the observation geometry, the UKR characteristics, and estimate the sensitivity for an instrument analogous to the Cassini Radio Plasma Wave Science (RPWS) but with a modified receiver digitizer and signal processing chain. We show that the concept has the potential to directly and unambiguously detect cold oceans within Uranian satellites and provide strong constraints on the interior structure in the presence of warm or no oceans. As part of a geophysical payload, the concept could therefore have a key role in the detection of oceans within the Uranian satellites. The main limitation of the concept is coherence losses attributed to the extended source size of the UKR and dependence on the illumination geometry. These factors represent constraints on the tour design of a future Uranus mission in terms of flyby altitudes and encounter timing.

The probability that life spontaneously emerges in a suitable environment (abiogenesis) is one of the major unknowns in astrobiology. Assessing its value is impeded by the lack of an accepted theory for the origin of life, and is further complicated by the existence of selection biases. Appealing uncritically to some version of the ``Principle of Mediocrity'' -- namely, the supposed typicality of what transpired on Earth -- is problematic on empirical or logical grounds. In this paper, we adopt a Bayesian statistical approach to put on rigorous footing the inference of lower bounds for the probability of abiogenesis, based on current and future evidence. We demonstrate that the single datum that life has appeared at least once on Earth merely sets weak constraints on the minimal probability of abiogenesis. In fact, the {\it a priori} probability assigned to this event (viz., optimistic, pessimistic or agnostic prior) exerts the strongest influence on the final result. We also show that the existence of a large number of habitable worlds does not necessarily imply, by itself, a high probability that life should be common in the universe. Instead, as delineated before, the choice of prior, which is subject to uncertainty (i.e., admits multiple scenarios), strongly influences the likelihood of life being common. If habitable worlds are uncommon, for an agnostic prior, a deterministic scenario for the origin of life might be favoured over one where abiogenesis is a fluke event.

We report on the annual variation of quiet-time suprathermal ion composition for C through Fe using Advanced Composition Explorer (ACE)/Ultra-Low Energy Isotope Spectrometer (ULEIS) data over the energy range 0.3 MeV/nuc to 1.28 MeV/nuc from 1998 through 2019, covering solar cycle 23's rising phase through Solar Cycle 24's declining phase. Our findings are (1) quiet time suprathermal abundances resemble CIR-associated particles during solar minima; (2) quiet time suprathermals are M/Q fractionated in a manner that is consistent with M/Q fractionation in large gradual solar energetic particle events (GSEP) during solar maxima; and (3) variability within the quiet time suprathermal pool increases as a function of M/Q and is consistent with the analogous variability in GSEP events. From these observations, we infer that quiet time suprathermal ions are remnants of CIRs in solar minima and GSEP events in solar maxima. Coincident with these results, we also unexpectedly show that S behaves like a low FIP ion in the suprathermal regime and therefore drawn from low FIP solar sources.

Context: Radio interferometers measure frequency components of the sky brightness, modulated by the gains of the individual radio antennas. Due to atmospheric turbulence and variations in the operational conditions of the antennas these gains fluctuate. Thereby the gains do not only depend on time but also on the spatial direction on the sky. To recover high quality radio maps an accurate reconstruction of the direction and time-dependent individual antenna gains is required. Aims: This paper aims to improve the reconstruction of radio images, by introducing a novel joint imaging and calibration algorithm including direction-dependent antenna gains. Methods: Building on the \texttt{resolve} framework, we designed a Bayesian imaging and calibration algorithm utilizing the image domain gridding method for numerically efficient application of direction-dependent antenna gains. Furthermore by approximating the posterior probability distribution with variational inference, our algorithm can provide reliable uncertainty maps. Results: We demonstrate the ability of the algorithm to recover high resolution high dynamic range radio maps from VLA data of the radio galaxy Cygnus A. We compare the quality of the recovered images with previous work relying on classically calibrated data. Furthermore we compare with a compressed sensing algorithm also incorporating direction-dependent gains. Conclusions: Including direction-dependent effects in the calibration model significantly improves the dynamic range of the reconstructed images compared to reconstructions from classically calibrated data. Compared to the compressed sensing reconstruction, the resulting sky images have a higher resolution and show fewer artifacts. For utilizing the full potential of radio interferometric data, it is essential to consider the direction dependence of the antenna gains.

Star formation rate functions (SFRFs) give an instantaneous view of the distribution of star formation rates (SFRs) in galaxies at different epochs. They are a complementary and more stringent test for models than the galaxy stellar mass function, which gives an integrated view of the past star formation activity. However, the exploration of SFRFs has been limited thus far due to difficulties in assessing the SFR from observed quantities and probing the SFRF over a wide range of SFRs. We overcome these limitations thanks to an original method that predicts the infrared luminosity from the rest-frame UV/optical color of a galaxy and then its SFR over a wide range of stellar masses and redshifts. We applied this technique to the deep imaging survey HSC-CLAUDS combined with near-infrared and UV photometry. We provide the first SFR functions with reliable measurements in the high- and low-SFR regimes up to $z=2$ and compare our results with previous observations and four state-of-the-art hydrodynamical simulations.

Precise, high-cadence, long-term records of stellar spectral variability at different temporal scales lead to better understanding of a wide variety of phenomena including stellar atmospheres and dynamos, convective motions, and rotational periods. Here, we investigate the variability of solar Balmer lines (H-$\alpha$, -$\beta$, -$\gamma$, -$\delta$) observed by space-borne radiometers (OSIRIS, SCIAMACHY, OMI, and GOME-2), combining these precise, long-term observations with high-resolution data from the ground-based NSO/ISS spectrograph. We relate the detected variability to the appearance of magnetic features on the solar disk. We find that on solar-rotational timescales (about 1 month), the Balmer line activity indices (defined as line-core to line-wing ratios) closely follow variations in the total solar irradiance (which is predominantly photospheric), thus frequently (specifically, during passages of sunspot groups) deviating from behavior of activity indices that track chromospheric activity levels. On longer timescales, the correlation with chromospheric indices increases, with periods of low- or even anti-correlation found at intermediate timescales. Comparison of these observations with estimates from semi-empirical irradiance reconstructions helps quantify the contributions of different magnetic and quiet features. We conclude that both the lower sensitivity to network and in part the higher sensitivity to filaments and prominences, may result in complex, time-dependent relationships between Balmer and other chromospheric indices observed for the Sun and solar-like stars. The fact that core and wings contribute in similar manner to the variability, and current knowledge of Balmer-lines formation in stellar atmospheres, support the notion that Balmer lines core-to-wing ratios indices behave more like photospheric rather than chromospheric indices.

The Dragonfly Galaxy (MRC 0152-209), the most infrared-luminous radio galaxy at redshift z~2, is a merger system containing a powerful radio source and large displacements of gas. We present kpc-resolution data from ALMA and the VLA of carbon monoxide (6-5), dust, and synchrotron continuum, combined with Keck integral-field spectroscopy. We find that the Dragonfly consists of two galaxies with rotating disks that are in the early phase of merging. The radio jet originates from the northern galaxy and brightens when it hits the disk of the southern galaxy. The Dragonfly Galaxy therefore likely appears as a powerful radio galaxy because its flux is boosted into the regime of high-z radio galaxies by the jet-disk interaction. We also find a molecular outflow of (1100 $\pm$ 550) M$_{\odot}$/yr associated with the radio host galaxy, but not with the radio hot-spot or southern galaxy, which is the galaxy that hosts the bulk of the star formation. Gravitational effects of the merger drive a slower and longer lived mass displacement at a rate of (170 $\pm$ 40) M$_{\odot}$/yr, but this tidal debris contain at least as much molecular gas mass as the much faster outflow, namely M(H2) = (3 $\pm$ 1) x 10$^9$ (alpha(CO)/0.8) M$_{\odot}$. This suggests that both the AGN-driven outflow and mass transfer due to tidal effects are important in the evolution of the Dragonfly system. The Keck data show Ly$\alpha$ emission spread across 100 kpc, and CIV and HeII emission across 35 kpc, confirming the presence of a metal-rich and extended circumgalactic medium previously detected in CO(1-0).

The amide-related molecules are essential for the formation of the other complex bio-molecules and an understanding of the prebiotic chemistry in the interstellar medium (ISM). We presented the first detection of the rotational emission lines of the amide-like molecule cyanamide (NH$_{2}$CN) towards the hot molecular core G358.93$-$0.03 MM1 using the Atacama Large Millimeter/Submillimeter Array (ALMA). Using the rotational diagram model, the derived column density of NH$_{2}$CN towards the G358.93$-$0.03 MM1 was (5.9$\pm$2.5)$\times$10$^{14}$ cm$^{-2}$ with a rotational temperature of 100.6$\pm$30.4 K. The derived fractional abundance of NH$_{2}$CN towards the G358.93$-$0.03 MM1 with respect to H$_{2}$ was (4.72$\pm$2.0)$\times$10$^{-10}$, which is very similar to the existent three-phase warm-up chemical model abundances of NH$_{2}$CN. We compare the estimated abundance of NH$_{2}$CN towards G358.93$-$0.03 MM1 with other sources, and we observe the abundance of NH$_{2}$CN towards G358.93$-$0.03 MM1 is nearly similar to that of the sculptor galaxy NGC 253 and the low-mass protostars IRAS 16293-2422 B and NGC 1333 IRAS4A2. We also discussed the possible formation mechanisms of NH$_{2}$CN towards the hot molecular cores and hot corinos, and we find that the NH$_{2}$CN molecule was created in the grain-surfaces of G358.93-0.03 MM1 via the neutral-neutral reaction between NH$_{2}$ and CN.

Data analysis in space sciences has been performed exclusively visually for years, despite the fact that the largest amount of data belongs to non-visible portions of the electromagnetic spectrum. This, on the one hand, limits the study of the unknown to the current resolution possibilities of the screens, and on the other hand, it excludes a group of people who present some type of visual disability. Taking into account the aforementioned, and that people with some type of disability encounter many barriers to achieve academic studies and stable jobs, the present investigation focuses on new modalities of access to the data, but taking into account the accessibility and inclusion of people with functional diversity from the beginning. It has been shown that multimodal perception (use of more than one sense) can be a good complement to visual exploration and understanding of complex scientific data. This is especially true for astrophysical data, composed of a sum of different oscillatory modes resulting in the final complex data array. This proposal focuses on the human ability to adapt to data and interaction with sound, in order to analyze data sets and produce an application aimed at leveling the possibilities of access to information in the field of physics and astronomy (although the tool is also applicable to any type of data in files with 2 or more columns (.txt or .csv)) for people with disabilities. In addition, it proposes the study of scientific and technological capacities for the generation of tools with a novel approach, focused on the user and oriented to: a specific social problem, the use of free programming languages and the design of infrastructure to improve inclusion.

We present Swift/Ultraviolet Optical Telescope (UVOT) integrated light photometry of the Spitzer Infrared Nearby Galaxies Survey (SINGS) and the Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel (KINGFISH) samples of nearby galaxies. Combining the Swift/UVOT data with archival photometry, we investigate a variety of dust attenuation curves derived using MCSED, a flexible spectral energy distribution fitting code. We fit the panchromatic data using three different star formation history (SFH) parameterizations: a decaying exponential, a double power law, and a piecewise function with breaks at physically motivated ages. We find that the average attenuation law of the sample changes slightly based on the SFH assumed. Specifically, the exponential SFH leads to the shallowest attenuation curves. Using simulated data, we also find the exponential SFH fails to outperform the more complex SFHs. Finally, we find a systematic offset in the derived bump strength between SED fits with and without UVOT data, where the inclusion of UVOT data leads to smaller bump strengths, highlighting the importance of the UVOT data. This discrepancy is not seen in fits to mock photometry. Understanding dust attenuation in the local universe is key to understanding high redshift objects where rest-frame far-infrared data is unavailable.

In this work, we perform the first systematic investigation of effects of the presence of dark matter on r-mode oscillations in neutron stars (NSs). Using a self-interacting dark matter (DM) model based on the neutron decay anomaly and a hadronic model obtained from the posterior distribution of a recent Bayesian analysis, we impose constraints on the DM self-interaction strength using recent multimessenger astrophysical observations. The constrained DM interaction strength is then used to estimate DM self-interaction cross section and shear viscosity resulting from DM, which is found to be several orders of magnitude smaller than shear viscosity due to hadronic matter. Assuming that the DM fermion is in chemical equilibrium with the neutrons in the neutron star, we estimate the bulk viscosity resulting from the dark decay of neutrons, and find it to be much smaller than the hadronic bulk viscosity. We also conclude that the instability window with minimal hadronic damping mechanisms can become smaller when including DM shear and bulk viscosity but remains incompatible with the X-ray and pulsar observational data for the chosen DM model.

We present a new version of MGCAMB, a patch for the Einstein-Boltzmann solver CAMB for cosmological tests of gravity. New features include a new cubic-spline parameterization allowing for a simultaneous reconstruction of $\mu$, $\Sigma$ and the dark energy density fraction $\Omega_X$ as functions of redshift, the option to work with a direct implementation of $\mu$, $\Sigma$ (instead of converting to $\mu$, $\gamma$ first), along with the option to test models with a scalar field coupled only to dark matter, and the option to include dark energy perturbations when working with $w\ne -1$ backgrounds, to restore consistency with CAMB in the GR limit. This version of MGCAMB comes with a python wrapper to run it directly from the python interface, an implementation in the latest version of CosmoMC, and can be used with Cobaya.

Cosmological first-order phase transitions (1stOPTs) are said to be strongly supercooled when the nucleation temperature is much smaller than the critical temperature. These are often encountered in theories that admit a nearly scale-invariant potential, for which the bounce action decreases only logarithmically with temperature. During supercooled 1stOPTs the equation of state of the universe undergoes a rapid and drastic change, transitioning from vacuum-domination to radiation-domination. The statistical variations in bubble nucleation histories imply that distinct causal patches percolate at slightly different times. Patches which percolate the latest undergo the longest vacuum-domination stage and as a consequence develop large over-densities triggering their collapse into primordial black holes (PBHs). We derive an analytical approximation for the probability of a patch to collapse into a PBH as a function of the 1stOPT duration, $\beta^{-1}$, and deduce the expected PBH abundance. We find that 1stOPTs which take more than $12\%$ of a Hubble time to complete ($\beta/H \lesssim 8$) produce observable PBHs. Their abundance is independent of the duration of the supercooling phase, in agreement with the de Sitter no hair conjecture.

The possibility of forming gravitational-wave sources with high center-of-mass (c.m.) velocities in the vicinity of supermassive black holes requires us to develop a method of deriving the waveform in the observer's frame. Here we show that in the limit where the c.m. velocity is high but the relative velocities of the components of the source are small, we can solve the problem by directly integrating the relaxed Einstein field equation. In particular, we expand the result into multipole components which can be conveniently calculated given the orbit of the source in the observer's frame. Our numerical calculations using arbitrary c.m. velocities show that the result is consistent with the Lorentz transformation of GWs to the leading order of the radiation field. Moreover, we show an example of using this method to calculate the waveform of a scattering event between the high-speed ($\sim 0.1c$) stellar objects embedded in the accretion disk of an active galactic nucleus. Our multipole-expansion method not only has advantages in analyzing the results from stellar-dynamical models but also provides new insight into the multipole properties of the GWs emitted from a high-speed source.

Inspired by the reconstruction scheme of the inflaton field potential $V(\phi)$ from the attractors$n_s(N)$, we investigate the viability of reconstruct the inflationary potential within the framework of k-inflation for a non-linear kinetic term $K(X)=k_{n+1}X^n$ through three expressions for the scalar spectral index $n_s(N)$, namely: (i) $n_s-1=-\frac{2}{N}$, (ii) $n_s-1=-\frac{p}{N}$, and (iii) $n_s-1=-\frac{\beta}{N^q}$. For each reconstructed potential, we determine the values of the parameter space which characterize it by requiring that it must reproduce the observable parameters from PLANCK 2018 and BICEP/Keck results. Furthermore, we analyze the reheating era by assuming a constant equation of state, in which we derive the relations between the reheating duration, the temperature at the end of reheating together with the reheating epoch, and the number of $e$-folds during inflation. In this sense, we unify the inflationary observables in order to narrow the parameter space of each model within the framework of the reconstruction in k-inflation.

While most scintillation-based dark matter experiments search for Weakly Interacting Massive Particles (WIMPs), a sub-GeV WIMP-like particle may also be detectable in these experiments. While dark matter of this type and scale would not leave appreciable nuclear recoil signals, it may instead induce ionization of atomic electrons. Accurate modelling of the atomic wavefunctions is key to investigating this possibility, with incorrect treatment leading to a large suppression in the atomic excitation factors. We have calculated these atomic factors for argon, krypton and xenon and present the tabulated results for use with a range of dark matter models. This is made possible by the separability of the atomic and dark matter form factor, allowing the atomic factors to be calculated for general couplings; we include tables for vector, scalar, pseudovector, and pseudoscalar electron couplings. Additionally, we calculate electron impact total ionization cross sections for xenon using the tabulated results as a test of accuracy. Lastly, we provide an example calculation of the event rate for dark matter scattering on electrons in XENON1T and show that these calculations depend heavily on how the low-energy response of the detector is modelled.

We consider constraints on $p$-wave dark matter in a dark matter spike surrounding the supermassive black hole at the center of M87. Owing to the large mass of the black hole, and resulting large velocity dispersion for the dark matter particles in the spike, it is possible for Fermi-LAT and MAGIC data to place tight constraints on $p$-wave annihilation, which would be far more stringent than those placed by observations of dwarf spheroidal galaxies. Indeed, for optimistic choices of the spike parameters, gamma-ray data would exclude thermal $p$-wave dark matter models with a particle mass $\lesssim {10}~\rm TeV$. But there is significant uncertainty in the properties and parameters of the spike, and for less optimistic scenarios, thermal dark matter candidates would be completely unconstrained. In addition to better understanding the spike parameters, a second key to improving constraints on dark matter annihilation is an accurate astrophysical background model.

We investigate the linear stability of scalarized black holes (BHs) and neutron stars (NSs) in the Einstein-scalar-Gauss-Bonnet (GB) theories against the odd- and even-parity perturbations including the higher multipole modes. We show that the angular propagation speeds in the even-parity perturbations in the $\ell \to \infty$ limit, with $\ell$ being the angular multipole moments, become imaginary and hence scalarized BH solutions suffer from the gradient instability. We show that such an instability appears irrespective of the structure of the higher-order terms in the GB coupling function and is caused purely due to the existence of the leading quadratic term and the boundary condition that the value of the scalar field vanishes at the spatial infinity.~This indicates that the gradient instability appears at the point in the mass-charge diagram where the scalarized branches bifurcate from the Schwarzschild branch. We also show that scalarized BH solutions realized in a nonlinear scalarization model also suffer from the gradient instability in the even-parity perturbations. Our result also suggests the gradient instability of the exterior solutions of the static and spherically-symmetric scalarized NS solutions induced by the same GB coupling functions.

Interplanetary Coronal Mass Ejections (ICMEs) are prominent drivers of space weather disturbances and mainly lead to intense or extreme geomagnetic storms. The reported studies suggested that the planar ICME sheath and planar magnetic clouds (MCs) cause extreme storms. Here, we investigated the severe two-step geomagnetic storm ($Dst \sim -187$ nT) of 25$^{th}$ solar cycle. Our analysis demonstrates flattened (pancaked) ICME structures, i.e., quasi-planar magnetic structures (PMS). The study corroborates our earlier reported finding that the less adiabatic expansion in quasi-PMS transformed ICME enhanced the strength of the southward magnetic field component. It contributes to the efficient transfer of plasma and energy in the Earth's magnetosphere to cause the observed severe storm.

The Rapid Acquisition Atmospheric Detector (RAAD), onboard the LIGHT-1 3U CubeSat, detects photons between hard X-rays and soft gamma-rays, in order to identify and characterize Terrestrial Gamma Ray Flashes (TGFs). Three detector configurations are tested, making use of Cerium Bromide and Lanthanum BromoChloride scintillating crystals coupled to photomultiplier tubes or Multi-Pixel Photon Counters, in order to identify the optimal combination for TGF detection. High timing resolution, a short trigger window, and the short decay time of its electronics allow RAAD to perform accurate measurements of prompt, transient events. Here we describe the overview of the detection concept, the development of the front-end acquisition electronics, as well as the ground testing and simulation the payload underwent prior to its launch on December 21st, 2021. We further present a preliminary analysis of the detector's housekeeping data collected in orbit to evaluate the health of the instrument in operating conditions.