Papers for Thursday, Jun 02 2022

The Oort cloud and the scattered disk are the two primary reservoirs for long-period and short-period comets, respectively. In this review, we assess the known observational constraints on these reservoirs' properties and their formation. In addition, we discuss how the early orbital evolution of the giant planets generated the modern scattered disk from the early, massive planetesimal disk and how $\sim$5\% of this material was captured into the Oort cloud. We review how the Sun's birth environment and dynamical history within the Milky Way alters the formation and modern structure of the Oort cloud. Finally, we assess how the coming decade's anticipated observing campaigns may provide new insights into the formation and properties of the Oort cloud and scattered disk.

Convection is ubiquitous in stars and occurs under many different conditions. Here we explore convection in main-sequence stars through two lenses: dimensionless parameters arising from stellar structure and parameters which emerge from the application of mixing length theory. We first define each quantity in terms familiar both to the 1D stellar evolution community and the hydrodynamics community. We then explore the variation of these quantities across different convection zones, different masses, and different stages of main-sequence evolution. We find immense diversity across stellar convection zones. Convection occurs in thin shells, deep envelopes, and nearly-spherical cores; it can be efficient of inefficient, rotationally constrained or not, transsonic or deeply subsonic. This atlas serves as a guide for future theoretical and observational investigations by indicating which regimes of convection are active in a given star, and by describing appropriate model assumptions for numerical simulations.

We show that if comets (or any small icy planetesimals such as Kuiper belt objects) are composed of pebble piles, their internal radiogenic as well as geochemical heating results in considerably different evolutionary outcomes compared to similar past studies. We utilize a 1D thermo-physical evolution code, modified to include state-of-the-art empirical measurements of pebble thermal conductivity and compression, the latter obtained through a new laboratory experiment presented here for the first time. Results indicate that due to the low pebble thermal conductivity, the peak temperatures attained during evolution are much higher than in any previous study given the same formation time. Assuming meteoritic radiogenic abundances, we find that only extremely small, sub-kilometre comets have the potential to retain the primordial, uniform and thermally unprocessed composition from which they formed. Comets with radii in excess of about 20 km are typically swept by rapid and energetically powerful aqueous hydration reactions. Across the full range of comet sizes and formation times, evolutions result in the processing and differentiation of various volatile species, and a radially heterogeneous nucleus stucture. Our computations however also indicate that the assumed fraction of radionuclides is a pivotal free parameter, because isotopic analyses of the only available cometary samples suggest that no 26Al was ever present in comet 81P/Wild 2. We show that if comets formed early in the protoplanetary disc (within 1-3 Myr), the radionuclide abundances indeed must be much smaller than those typically assumed based on meteoritic samples. We discuss the importance of our findings for the formation, present-day attributes and future research of comets.

We present new analysis of infrared transmission spectroscopy of the cloud-free hot-Saturn WASP-96b performed with the Hubble and Spitzer Space Telescopes (HST and Spitzer). The WASP-96b spectrum exhibits the absorption feature from water in excellent agreement with synthetic spectra computed assuming a cloud-free atmosphere. The HST-Spitzer spectrum is coupled with Very Large Telescope (VLT) optical transmission spectroscopy which reveals the full pressure-broadened profile of the sodium absorption feature and enables the derivation of absolute abundances. We confirm and correct for a spectral offset of $\Delta R_{{\rm p}}/R_{\ast}=(-4.29^{+0.31}_{-0.37})\,\times10^{-3}$ of the VLT data relative to the HST-Spitzer spectrum. This offset can be explained by the assumed radius for the common-mode correction of the VLT spectra, which is a well-known feature of ground-based transmission spectroscopy. We find evidence for a lack of chromospheric and photometric activity of the host star which, therefore, make a negligible contribution to the offset. We measure abundances for Na and O that are consistent with solar to supersolar, with abundances relative to solar values of $21^{+27}_{-14}$ and $7^{+11}_{-4}$, respectively. We complement the transmission spectrum with new thermal emission constraints from Spitzer observations at 3.6 and $4.5\mu$m, which are best explained by the spectrum of an atmosphere with a temperature decreasing with altitude. A fit to the spectrum assuming an isothermal blackbody atmosphere constrains the dayside temperature to be $T_{\rm{p}}$=$1545$$\pm$$90$K.

We present band 6 ALMA observations of a heavily-obscured radio-loud ($L_{1.4\ \mathrm{GHz}}=10^{25.4}$ W Hz$^{-1}$) AGN candidate at $z_\mathrm{phot}=6.83\pm0.06$ found in the 1.5 deg$^2$ COSMOS field. The ALMA data reveal detections of exceptionally strong [CII]158$\mu$m ($z_\mathrm{[CII]}=6.8532$) and underlying dust continuum emission from this object (COS-87259), where the [CII] line luminosity, line width, and 158$\mu$m continuum luminosity are comparable to that seen from $z\sim7$ sub-mm galaxies and quasar hosts. The 158$\mu$m continuum detection suggests a total infrared luminosity of $9\times10^{12}$ $L_\odot$ with corresponding very large obscured star formation rate (1300 $M_\odot$/yr) and dust mass ($2\times10^9$ $M_\odot$). The apparent strong Balmer break seen between the VIRCam and IRAC photometry suggests that COS-87259 is an extremely massive reionization era galaxy with $M_\ast\approx1.7\times10^{11}$ $M_\odot$. Moreover, the MIPS, PACS, and SPIRE detections imply that this object harbors an AGN that is heavily obscured ($\tau_{_{\mathrm{9.7\mu m}}}=2.3$) with a bolometric luminosity of approximately $5\times10^{13}$ $L_\odot$. Such a very high AGN luminosity suggests this object is powered by an $\approx$1.6 $\times$ 10$^9$ $M_\odot$ black hole if accreting near the Eddington limit, and is effectively a highly-obscured version of an extremely UV-luminous ($M_{1450}\approx-27.3$) $z\sim7$ quasar. Notably, these $z\sim7$ quasars are an exceedingly rare population ($\sim$0.001 deg$^{-2}$) while COS-87259 was identified over a relatively small field. Future very wide-area surveys with, e.g., Roman and Euclid have the potential to identify many more extremely red yet UV-bright $z\gtrsim7$ objects similar to COS-87259, providing richer insight into the occurrence of intense obscured star formation and supermassive black hole growth among this population.

Massive elliptical galaxies can display structures that deviate from a pure elliptical shape, such as a twist of the principal axis or variations in the axis ratio with galactocentric distance. Although satisfactory lens modeling is generally achieved without accounting for these azimuthal structures, the question about their impact on inferred lens parameters remains, in particular, on time delays as they are used in time-delay cosmography. This paper aims at characterizing these effects and quantifying their impact considering realistic amplitudes of the variations. We achieved this goal by creating mock lensing galaxies with morphologies based on two data sets: observational data of local elliptical galaxies, and hydrodynamical simulations of elliptical galaxies at a typical lens redshift. We then simulated images of the lensing systems with space-based data quality and modeled them in a standard way to assess the impact of a lack of azimuthal freedom in the lens model. We find that twists in lensing galaxies are easily absorbed in homoeidal lens models by a change in orientation of the lens up to 10{\deg} with respect to the reference orientation at the Einstein radius, and of the shear by up to 20{\deg} with respect to the input shear orientation. The ellipticity gradients, on the other hand, can introduce a substantial amount of shear that may impact the radial mass model and consequently bias $H_0$, up to 10 km/s/Mpc. However, we find that light is a good tracer of azimuthal structures, meaning that direct imaging should be capable of diagnosing their presence. This in turn implies that such a large bias is unlikely to be unaccounted for in standard modeling practices. Furthermore, the overall impact of twists and ellipticity gradients averages out at a population level. For the galaxy populations we considered, the cosmological inference remains unbiased.

White dwarf (WD) stars evolve simply and predictably, making them reliable age indicators. However, self-consistent validation of the methods for determining WD total ages has yet to be widely performed. This work uses 1565 wide ( > 100 au) WD+WD binaries and 24 new triples containing at least two WDs to test the accuracy and validity of WD total age determinations. For these 1589 wide double-WD binaries and triples, we derive total ages of each WD using photometric data from all-sky surveys, in conjunction with Gaia parallaxes and current hydrogen-atmosphere WD models. Ignoring initial-to-final-mass relations and considering only WD cooling ages, we find that roughly 21-36% of the more massive WDs in a system have a shorter cooling age. Since more massive WDs should be born as more massive main-sequence stars, we attribute this unphysical disagreement as evidence of prior mergers or the presence of an unresolved companion, suggesting that roughly 21-36% of wide WD+WD binaries were once triples. Among the 423 wide WD+WD pairs that pass high-fidelity cuts, we find that 25% total age uncertainties are generally appropriate for WDs with masses > 0.63 Msun and temperatures < 12,000 K, and provide suggested inflation factors for age uncertainties for higher-mass WDs. Overall, WDs return reliable stellar ages, but we detail cases where total ages are least reliable, especially for WDs < 0.63 Msun.

Saturn's Moon Titan receives volatiles into the top of its atmosphere-including atomic oxygen-sourced from cryovolcanoes on Enceladus. Similar types of atmosphere exchange from one body to another, such as O2 and O3 sourced from TRAPPIST-1 d, could be introduced into the upper atmosphere of TRAPPIST-1 e and might be interpreted as biosignatures. We simulate this potential false-positive for life on TRAPPIST-1 e, by applying an external influx of water and oxygen into the top of the atmosphere using a coupled 1-D photochemical-climate model (Atmos), to predict atmospheric composition. In addition, synthetic spectral observations are produced using the Planetary Spectrum Generator for the James Webb Space Telescope, Origins Space Telescope, Habitable Exoplanet Observatory and Large Ultra-violet/Optical/Infrared Surveyor to test the detectability of abiotic-generated O2 and O3 in the presence of abiotic and biotic surface fluxes of CH4. We determine that the incoming flux of material needed to trigger detection of abiotic O2/O3 by any of these observatories is more than two orders of magnitude (1E12 molecules/cm2/s) above what is physically plausible.

Technosignatures refer to observational manifestations of technology that could be detected through astronomical means. Most previous searches for technosignatures have focused on searches for radio signals, but many current and future observing facilities could also constrain the prevalence of some non-radio technosignatures. This search could thus benefit from broader participation by the astronomical community, as contributions to technosignature science can also take the form of negative results that provide statistically meaningful quantitative upper limits on the presence of a signal. This paper provides a synthesis of the recommendations of the 2020 TechnoClimes workshop, which was an online event intended to develop a research agenda to prioritize and guide future theoretical and observational studies technosignatures. The paper provides a high-level overview of the use of current and future missions to detect exoplanetary technosignatures at ultraviolet, optical, or infrared wavelengths, which specifically focuses on the detectability of atmospheric technosignatures, artificial surface modifications, optical beacons, space engineering and megastructures, and interstellar flight. This overview does not derive any new quantitative detection limits but is intended to provide additional science justification for the use of current and planned observing facilities as well as to inspire astronomers conducting such observations to consider the relevance of their ongoing observations to technosignature science. This synthesis also identifies possible technology gaps with the ability of current and planned missions to search for technosignatures, which suggests the need to consider technosignature science cases in the design of future mission concepts.

Early Mars had rivers, but the cause of Mars' wet-to-dry transition remains unknown. Past climate on Mars can be probed using the spatial distribution of climate-sensitive landforms. We analyzed global databases of water-worked landforms and identified changes in the spatial distribution of rivers over time. These changes are simply explained by comparison to a simplified meltwater model driven by an ensemble of global climate model simulations, as the result of $\gtrsim$10 K global cooling, from global average surface temperature (T) $\ge$ 268 K to T $\sim$ 258 K, due to a weaker greenhouse effect. In other words, river-forming climates on Early Mars were warm and wet first, and cold and wet later. Surprisingly, analysis of the greenhouse effect within our ensemble of global climate model simulations suggests that this shift was primarily driven by waning non-CO2 radiative forcing, and not changes in CO2 radiative forcing.

In this work we make use of a general relativistic method to estimate the mass-to-distance ratio M/D = 3.54^{+0.2}_{-0.2} X 10^4 M_{sun}/Mpc of the black hole hosted at the core of the active galactic nucleus of TXS 2226-184, along with its Right Ascension offset and the recession redshift (velocity) of the galaxy. Our statistical fit is based on the frequency shift of photons emitted by water masers and their orbital positions when circularly revolving around the black hole center within the accretion disk of the active galactic nucleus. By taking into account a previously reported distance to the galaxy, we compare the result of the black hole mass fit to an estimate based on a mass-luminosity correlation. We find that the black hole mass at the core of TXS 2226-184 obtained with the aid of the statistical fit using the general relativistic method, M = 3.67 ^{+0.2}_{-0.2} X 10^6 M_{sun}, is approximately 0.6 times the black hole mass, M_{BH} = 6.24^{+3.6}_{-2.3} X 10^6 M_{sun}, computed with the mass-luminosity correlation.

We investigate the spatial distribution of the satellites of isolated host galaxies in the IllustrisTNG100-1 simulation. In agreement with a previous, similar analysis of the Illustris-1 simulation, the satellites are typically poor tracers of the mean host mass density. Unlike the Illustris-1 satellites, here the spatial distribution of the complete satellite sample is well-fitted by an NFW profile; however, the concentration is a factor of ~2 lower than that of the mean host mass density. The spatial distribution of the brightest 50% and faintest 50% of the satellites are also well-fitted by NFW profiles, but the concentrations differ by a factor of ~2. When the sample is subdivided by host color and luminosity, the number density profiles for blue satellites generally fall below the mean host mass density profiles while the number density profiles for red satellites generally rise above the mean host mass density profiles. These opposite, systematic offsets combine to yield a moderately good agreement between the mean mass density profile of the brightest blue hosts and the corresponding number density profile of their satellites. Lastly, we subdivide the satellites according to the redshifts at which they joined their hosts. From this, we find that neither the oldest one third of the satellites nor the youngest one third of the satellites faithfully trace the mean host mass density.

Asteroseismology has become widely accepted as a benchmark for accurate and precise fundamental stellar properties. It can therefore be used to validate and calibrate stellar parameters derived from other approaches. Meanwhile, one can leverage archival and ongoing large-volume surveys in photometry, spectroscopy, and astrometry to infer stellar parameters over a wide range of evolutionary stages, independently of asteroseismology. Our pipeline, $\texttt{SEDEX}$, compares the spectral energy distribution predicted by the MARCS and BOSZ model spectra with 32 photometric bandpasses, combining data from 9 major, large-volume photometric surveys. We restrict the analysis to targets with available spectroscopy to lift the temperature-extinction degeneracy. Validation of our method and results with CHARA interferometry, HST CALSPEC spectrophotometry, and asteroseismology, shows that we achieve high precision and accuracy. We present improved interstellar extinction ($\sigma_{A_V} \simeq$ 0.08 mag) and stellar radii ($\sigma_R/R \simeq$ 3.6%) for $\sim$1.5 million stars in the low- to high-extinction ($A_V \lesssim 6 $ mag) fields observed by the APOGEE, GALAH, and RAVE spectroscopic surveys. We derive global extinctions for 191 Gaia DR2 open clusters. We confirm the differential extinction in NGC 6791 ($A_V=0.2$ to $0.6$ mag) and NGC 6819 ($A_V=0.4$ to $0.6$ mag) that have been subject to extensive asteroseismic analysis.

We present the results from a dense multi-wavelength (optical/UV, IR, and X-ray) follow-up campaign of the nuclear transient AT 2017gge, covering a total of 1698 days from the transient's discovery. The bolometric light-curve, the black body temperature and radius, as well as the broad H and He I $\lambda$5876 emission lines and their evolution with time, are all consistent with a TDE nature. A soft X-ray flare is detected with a delay of ~200 days with respect to the optical/UV peak and it is rapidly followed by the emergence of a broad He II $\lambda$4686 and by a number of long-lasting high ionization coronal emission lines. An IR echo, resulting from dust re-radiation of the optical/UV TDE light is observed after the X-ray flare and the associated near-IR spectra show a transient broad feature in correspondence of the He I $\lambda$10830. The data are well explained by a scenario in which a TDE occurs in a gas and dust rich environment and its optical/UV, soft X-ray, and IR emission have different origins and locations. The optical emission may be produced by stellar debris stream collisions prior to the accretion disk formation, which is instead responsible for the soft X-ray flare, emitted after the end of the circularization process.

It has been demonstrated that planets belonging to the same close-in, compact multiple-planet system tend to exhibit a striking degree of uniformity in their sizes. A similar trend has also been found to hold for the masses of such planets, but considerations of such intra-system mass uniformity have generally been limited to statistical samples wherein a majority of systems have constituent planetary mass measurements obtained via analysis of transit timing variations (TTVs). Since systems with strong TTV signals typically lie in or near mean motion resonance, it remains to be seen whether intra-system mass uniformity is still readily emergent for non-resonant systems with non-TTV mass provenance. We thus present in this work a mass uniformity analysis of 17 non-TTV systems with masses measured via radial velocity (RV) measurements. Using the Gini index, a common statistic for economic inequality, as our primary metric for uniformity, we find that our sample of 17 non-TTV systems displays intra-system mass uniformity at a level of $\sim 2.5 \sigma$ confidence. We provide additional discussion of possible statistical and astrophysical underpinnings for this result. We also demonstrate the existence of a correlation ($r = 0.25$) between characteristic solid surface density ($\Sigma_0$) of the minimum mass extrasolar nebula (MMEN) and system mass Gini index, suggesting that more massive disks may generally form systems with more unequal planetary masses.

Hydrodynamic and magnetohydrodynamic (MHD) turbulence in the early Universe can drive gravitational waves (GWs) and imprint their spectrum onto that of GWs, which might still be observable today. We study the production of the GW background from freely decaying MHD turbulence for helical and nonhelical initial magnetic fields. To understand the produced GW spectra, we develop a simple model on the basis of the evolution of the magnetic stress tensor. We find that the GW spectra obtained in this model reproduce those obtained in numerical simulations if we consider the time evolution of the low frequency tail of the stress spectrum from numerical simulations. We also show that the shapes of the produced GW frequency spectra are different for helical and nonhelical cases for the same initial magnetic energy spectra. Such differences can help distinguish helical and nonhelical initial magnetic fields from a polarized background of GWs -- especially when the expected circular polarization cannot be detected directly.

Some of the small-scale solar magnetic flux can be attributed to a small-scale dynamo (SSD) operating in the near-surface convection. The SSD fields have consequences for solar granular convection, basal flux, as well as chromospheric heating. A similar SSD mechanism is expected to be active in the near-surface convection of other cool main-sequence stars, but this has never been investigated. We aim to investigate changes in stratification and convection due to inclusion of SSD fields for F3V, G2V, K0V and M0V spectral types in the near-surface convection. 3D magnetohydrodynamic (MHD) models of the four stellar boxes, covering the subsurface convection zone up to the lower photosphere in a small cartesian box, are studied using the \textit{MURaM} radiative-MHD simulation code. The SSD runs are compared against reference hydrodynamic runs. An SSD is found to efficiently produce magnetic field with energies ranging between 5\% to 80\% of the plasma kinetic energy at different depths. This ratio tends to be larger for larger $T_{\mathrm{eff}}$. The relative change in density and gas pressure stratification for the deeper convective layers due to SSD magnetic fields is negligible, except for the F-star. For the F-star, there is a substantial reduction in convective velocities due to Lorentz force feedback from magnetic fields, which, in turn, reduces the turbulent pressure. SSD in near-surface convection for cool main-sequence stars introduces small but significant changes in thermodynamic stratification (especially for the F-star) due to reduction in convective velocities.

Using the publicly available eROSITA Final Equatorial Depth Survey (eFEDS) data, we detect the stacked X-ray emissions at the position of 463 filaments at a significance of 3.8 sigma. The filaments were identified with galaxies in the Sloan Digital Sky Survey survey, ranging from 30 Mpc to 100 Mpc in length at 0.2 < z < 0.6. The stacking of the filaments is performed with the eFEDS X-ray count-rate maps in the energy range between 0.4 - 2.3 keV after masking the resolved galaxy groups and clusters and the identified X-ray point sources from the ROSAT, Chandra, XMM, and eROSITA observations. In addition, the diffuse X-ray foreground and background emissions are removed by subtracting the signal in the region between 10 - 20 Mpc from the filament spines. For the stacked signal, we perform an X-ray spectral analysis, indicating the signal is associated with a thermal emission. Assuming the plasma emission with the Astrophysical Plasma Emission Code (APEC) model and a beta-model gas distribution with beta=2/3, the detected X-ray signal can be interpreted as an emission from hot gas in the filaments with an average gas temperature of 0.8 (+0.3, -0.2) keV and a gas overdensity of 41 +- 11 at the center of the filaments.

We have combined X-ray observations from Chandra with Sunyaev-Zel'dovich (SZ) effect data from Planck and Bolocam to measure intra-cluster medium pressure profiles from 0.03R$_{500}$ $\le$ R $\le$ 5R$_{500}$ for a sample of 21 low-$z$ galaxy clusters with a median redshift $\langle z \rangle = 0.08$ and a median mass $\langle \textrm{M}_{500} \rangle = 6.1 \times 10^{14}$ M$_{\odot}$ and a sample of 19 mid-$z$ galaxy clusters with $\langle z \rangle = 0.50$ and $\langle \textrm{M}_{500} \rangle = 10.6 \times 10^{14}$ M$_{\odot}$. The mean scaled pressure in the low-$z$ sample is lower at small radii and higher at large radii, a trend that is accurately reproduced in similarly selected samples from The300 simulations. This difference appears to be primarily due to dynamical state at small radii, evolution at intermediate radii, and a combination of evolution and mass dependence at large radii. Furthermore, the overall flattening of the mean scaled pressure profile in the low-$z$ sample compared to the mid-$z$ sample is consistent with expectations due to differences in mass accretion rate and the fractional impact of feedback mechanisms. In agreement with previous studies, the fractional scatter about the mean scaled pressure profile reaches a minimum of $\simeq 20$ per cent near 0.5R$_{500}$. This scatter is consistent between the low-$z$ and mid-$z$ samples at all radii, suggesting it is not strongly impacted by sample selection, and this general behavior is reproduced in The300 simulations. Finally, analytic functions that approximately describe the mass and redshift trends in mean pressure profile shape are provided.

AGN feedback stands for the dramatic impact that a SMBH can make on its environment. It has become an essential element of models that describe the formation and evolution of baryons in massive virialized halos. The baryons' radiative losses in the cores of these halos might lead to massive cooling and vigorous star formation on the order of 10-1000 Msun/yr, whereas observations show that the star formation rates are considerably less. It has now become clear from an observational, theoretical and simulation perspective that the activity of the central SMBH compensates for gas cooling losses and prevents very high star formation rates in massive galaxies, which otherwise would be much brighter than observed today. While AGN feedback is important over a broad range of halo masses, the most massive objects like galaxy groups and clusters truly provide outstanding laboratories for understanding the intrinsic details of AGN feedback. Partly, this is because in the nearby massive objects we can directly see what AGN feedback is doing to its surrounding hot halo in exquisite details, as opposed to less massive systems. Yet another reason is that in the most massive objects, the magnitude of AGN feedback has to be extremely large, providing the most stringent constraints. In a nutshell, the AGN feedback paradigm in groups and clusters postulates that (i) a SMBH in the center of a halo can release a vast amount of energy, (ii) this energy can be intercepted and thermalized by the gaseous atmosphere and (iii) the system self-regulates so that the energy released scales with the properties of the halo. A combination of multi-wavelength observations provides compelling evidence of the AGN feedback importance. Similarly, theoretical arguments suggest that self-regulation might be a natural property of a system consisting of a gaseous atmosphere and a SMBH at the bottom of the potential well.

We present the stability analysis of two regions, OMC-3 and OMC-4, in the massive and long molecular cloud complex of Orion A. We obtained $214~\mu$m HAWC+/SOFIA polarization data, and we make use of archival data for the column density and C$^{18}$O (1-0) emission line. We find clear depolarization in both observed regions and that the polarization fraction is anti-correlated with the column density and the polarization-angle dispersion function. We find that the filamentary cloud and dense clumps in OMC-3 are magnetically supercritical and strongly subvirial. This region should be in the gravitational collapse phase and is consistent with many young stellar objects (YSOs) forming in the region. Our histogram of relative orientations (HROs) analysis shows that the magnetic field is dynamically sub-dominant in the dense gas structures of OMC-3. We present the first polarization map of OMC-4. We find that the observed region is generally magnetically subcritical except for an elongated dense core, which could be a result of projection effect of a filamentary structure aligned close to the line-of-sight. The relative large velocity dispersion and the unusual positive shape parameters at high column densities in the HROs analysis suggest that our viewing angle may be close to axes of filamentary substructures in OMC-4. The dominating strong magnetic field in OMC-4 is unfavorable for star formation and is consistent with much fewer YSOs than in OMC-3.

The Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts (PASSAGES) project aims to identify a population of extremely luminous galaxies using the Planck All-Sky Survey and to explore the nature of their gas fuelling, induced starburst, and the resulting feedback that shape their evolution. Here, we report the identification of 22 high redshift luminous dusty star forming galaxies (DSFGs) at $z=1.1-3.3$ drawn from a candidate list constructed using the Planck Catalog of Compact Sources (PCCS) and WISE All-Sky Survey. They are confirmed through follow-up dust continuum imaging and CO spectroscopy using AzTEC and the Redshift Search Receiver (RSR) on the Large Millimeter Telescope Alfonso Serrano (LMT). Their apparent IR luminosities span $(0.1-3.1)\times 10^{14} L_\odot$ (median of $1.2\times10^{14}L_\odot$), making them some of the most luminous galaxies found so far. They are also some of the rarest objects in the sky with a source density of $\lesssim0.01$ deg$^{-2}$. Our Atacama Large Millimeter/submillimeter Array (ALMA) 1.1 mm continuum observations with $\theta$ $\approx$ 0.4" resolution show clear ring or arc morphologies characteristic of strong lensing. Their lensing-corrected luminosity of $L_{\rm IR}\gtrsim 10^{13}L_\odot$ ($SFR\gtrsim10^3 M_\odot$ yr$^{-1}$) indicates that they are the magnified versions of the most intrinsically luminous DSFGs found at these redshifts. Our spectral energy distribution (SED) analysis finds little detectable AGN activity despite their enormous luminosity, and any AGN activity present must be extremely heavily obscured.

We use archival Herschel data to examine the singly ionized carbon ([CII]) content of 14 star forming dwarf galaxies in the Virgo cluster. We use spectral energy distribution (SED) fits to far infrared, mid infrared, near infrared, optical and ultraviolet data to derive the total infrared continuum (TIR) for these galaxies. We compare the [CII]/TIR ratio for dwarf galaxies in the central part of Virgo to those in the southern part of the cluster and to galaxies with similar TIR luminosities and metallicities in the Herschel Dwarf Galaxy Survey (DGS) sample of field dwarf galaxies to look for signs of [CII] formation independent of star formation. Our analysis indicates that the sample of Virgo dwarfs in the central part of the cluster has significantly higher values of [CII]/TIR than the sample from the southern part of the cluster and the sample from the DGS, while the southern sample is consistent with the DGS. This [CII]/TIR excess implies that a significant fraction of the [CII] in the dwarf galaxies in the cluster center has an origin other than star formation and is likely to be due to environmental processes in the central part of the cluster. We also find a surprisingly strong correlation between [CII]/TIR and the local ram pressure felt by the dwarf galaxies in the cluster. In this respect, we claim that the excess [CII] we see in these galaxies is likely to be due to formation in ram pressure shocks.

The ability to collect unprecedented amounts of astronomical data has enabled the studying scientific questions that were impractical to study in the pre-information era. This study uses large datasets collected by four different robotic telescopes to profile the large-scale distribution of the spin directions of spiral galaxies. These datasets cover the Northern and Southern hemispheres, in addition to data acquired from space by the Hubble Space Telescope. The data were annotated automatically by a fully symmetric algorithm, as well as manually through a long labor-intensive process, leading to a dataset of nearly $10^6$ galaxies. The data shows possible patterns of asymmetric distribution of the spin directions, and the patterns agree between the different telescopes. The profiles also agree when using automatic or manual annotation of the galaxies, showing very similar large-scale patterns. Combining all data from all telescopes allows the most comprehensive analysis of its kind to date in terms of both the number of galaxies and the footprint size. The results show a statistically significant profile that is consistent across all telescopes. The instruments used in this study are DECam, HST, SDSS, and Pan-STARRS. The paper also discusses possible sources of bias, and analyzes the design of previous work that showed different results. Further research will be required to understand and validate these preliminary observations.

iPTF14hls is a luminous Type II supernova (SN) with a bumpy light curve that remains debated for its origin. It maintains roughly a constant effective temperature and luminosity since discovery for about 600 days, followed by a slow decay. On $\sim 1000$\ days post discovery the light curve transitions to a very steep decline. A spectrum taken during this steep decline phase shows clear signatures of shock interaction with dense circumstellar medium (CSM). Here we explore the possibility of iPTF14hls as an interaction-powered SN. The light curve of iPTF14hls can be fitted with wind-like CSMs. Analytic modeling indicates that iPTF14hls may have undertaken six episodes of mass loss during the last $\sim 200\mathrm{yr}$. Assuming that the 1954 eruption triggered the last mass-loss episode, the stellar-wind velocity is determined to be $40-70\mathrm{km}\mathrm{s}^{-1}$, depending on different models. Mass loss rates are in the range $% 0.4-3.3M_{\odot }\mathrm{yr}^{-1}$. The inferred total mass of ejecta and CSMs ($M_{\mathrm{ej}}+M_{\mathrm{CSMs}}\simeq 245M_{\odot }$) supports the idea that iPTF14hls may be a candidate for a (pulsational) pair-instability SN. Discovery and observations of more similar stellar explosions will help understand these peculiar SNe.

We present a detailed study of the high mass X-ray binary Vela X-1, using observations performed by Insight-HXMT in 2019 and 2020, concentrating on timing analysis and spectral studies including pulse phase-resolved spectroscopy. The cyclotron line energy is found to be at ~21-27 keV and 43-50 keV for the fundamental and first harmonic, respectively. We present the evolution of spectral parameters and find that two line centroid energy ratio E2/E1 evolved from ~2 before MJD 58900 to ~1.7 after that. The harmonic cyclotron line energy has no relation to the luminosity but the fundamental line energy shows a positive correlation with X-ray luminosity, suggesting that Vela X-1 is located in the sub-critical accreting regime. In addition, the pulse phase-resolved spectroscopy in Vela X-1 is performed. Both the CRSF and continuum parameters show strong variability over the pulse phase with the ratio of two line energies about 2 near the peak phases, and down to ~1.6 around off-peak phases. Long-term significant variations of the absorption column density and its evolution over the pulse phase may imply the existence of the clumpy wind structure near the neutron star.

Accretion disks are an essential component in the paradigm of the formation of low-mass stars. Recent observations further identify disks surrounding low-mass pre-main-sequence stars perturbed by flybys. Whether disks around more massive stars evolve in a similar manner becomes an urgent question. We report the discovery of a Keplerian disk of a few solar masses surrounding a 32 solar-mass protostar in the Sagittarius C cloud around the Galactic Center. The disk is gravitationally stable with two embedded spirals. A combined analysis of analytical solutions and numerical simulations demonstrates that the most likely scenario to form the spirals is through external perturbations induced by a close flyby, and one such perturber with the expected parameters is identified. The massive, early O-type star embedded in this disk forms in a similar manner with respect to low-mass stars, in the sense of not only disk-mediated accretion, but also flyby-impacted disk evolution.

We have carried out a study of the interstellar medium (ISM) toward a shell-like supernova remnant SNR Puppis A by using the NANTEN CO and ATCA HI data. We synthesized a comprehensive picture of the SNR radiation by combining the ISM data with the gamma ray and X-ray distributions. The ISM, both atomic and molecular gas, is dense and highly clumpy, and is distributed along the northeastern edge of the SNR shell. The CO distribution revealed an enhanced line intensity ratio of CO($J$ = 2-1)/($J$ = 1-0) transitions as well as CO line broadening, which indicate shock heating/acceleration. Further, the velocity distribution of CO and HI shows signs of expansion at $\sim$10 km s$^{-1}$ in the receding part of the shell. The ISM interacting with the SNR has large mass of $\sim$10$^{4}$ $M_{\odot}$ which is dominated by HI, showing good spatial correspondence with the Fermi-LAT gamma ray image. This favors the hadronic origin of the gamma rays, while additional contribution of the leptonic component is not excluded. The distribution of the X-ray ionization timescales within the shell suggests that the shock front ionized various parts of the ISM at epochs ranging over a few to ten 1000 yr. We therefore suggest that the age of the SNR is around 10$^{4}$ yr as given by the largest ionization timescale. We estimate the total cosmic ray energy $W_{\rm p}$ to be 10$^{47}$ erg, which is well placed in the cosmic ray escaping phase of an age-$W_{\rm p}$ plot including more than ten SNRs.

The semi-analytical model A-SLOTH (Ancient Stars and Local Observables by Tracing Halos) is the first public code that connects the formation of the first stars and galaxies to observables. After several successful projects with this model, we publish the source code and describe the public version in this paper. The model is based on dark matter merger trees that can either be generated based on Extended Press-Schechter theory or that can be imported from dark matter simulations. On top of these merger trees, A-SLOTH applies analytical recipes for baryonic physics to model the formation of both metal-free and metal-poor stars and the transition between them with unprecedented precision and fidelity. A-SLOTH samples individual stars and includes radiative, chemical, and mechanical feedback. It is calibrated based on six observables, such as the optical depth to Thomson scattering, the stellar mass of the Milky Way and its satellite galaxies, the number of extremely-metal poor stars, and the cosmic star formation rate density at high redshift. A-SLOTH has versatile applications with moderate computational requirements. It can be used to constrain the properties of the first stars and high-z galaxies based on local observables, predicts properties of the oldest and most metal-poor stars in the Milky Way, can serve as a subgrid model for larger cosmological simulations, and predicts next-generation observables of the early Universe, such as supernova rates or gravitational wave events.

With an unprecedented astrometric and photometric data precision, Gaia EDR3 gives us, for the first time, the opportunity to systematically detect and map in the optical bands, the low mass populations of the star forming regions (SFRs) in the Milky Way. We provide a catalogue of the Gaia EDR3 data (photometry, proper motions and parallaxes) of the young stellar objects (YSOs) identified in the Galactic Plane (|b|<30 deg) within about 1.5 kpc. The catalogue of the SFRs to which they belong is also provided to study the properties of the very young clusters and put them in the context of the Galaxy structure. We applied the machine learning unsupervised clustering algorithm DBSCAN on a sample of Gaia EDR3 data photometrically selected on the region where very young stars (t<10 Myr) are expected to be found, with the aim to identify co-moving and spatially consistent stellar clusters. A subsample of 52 clusters, selected among the 7323 found with DBSCAN, has been used as template data set, to identify very young clusters from the pattern of the observed color-absolute magnitude diagrams through a pattern match process. We find 124440 candidate YSOs clustered in 354 SFRs and stellar clusters younger than 10 Myr and within about 1.5 Kpc. In addition, 65863 low mass members of 322 stellar clusters located within about 500 pc and with ages 10 Myr<t<100 Myr were also found. The selected YSOs are spatially correlated with the well known SFRs. Most of them are associated with well concentrated regions or complex structures of the Galaxy and a substantial number of them have been recognized for the first time. The massive SFRs, such as, for example, Orion, Sco-Cen and Vela, located within 600-700 pc trace a very complex three-dimensional pattern, while the farthest ones seem to follow a more regular pattern along the Galactic Plane.

Globular clusters (GCs) are thought to harbor the long-sought population of intermediate-mass black holes (IMBHs). We present a systematic search for a putative IMBH in 81 Milky Way GCs, based on archival Chandra X-ray observations. We find in only six GCs a significant X-ray source positionally coincident with the cluster center, which have 0.5-8 keV luminosities between $\sim1\times 10^{30}~{\rm erg~s^{-1}}$ to $\sim 4\times10^{33}~{\rm erg~s^{-1}}$. However, the spectral and temporal properties of these six sources can also be explained in terms of binary stars. The remaining 75 GCs do not have a detectable central source, most with $3\sigma$ upper limits ranging between $10^{29-32}~{\rm erg~s^{-1}}$ over 0.5-8 keV, which are significantly lower than predicted for canonical Bondi accretion. To help understand the feeble X-ray signature, we perform hydrodynamic simulations of stellar wind accretion onto a $1000~{\rm M_\odot}$ IMBH from the most-bound orbiting star, for stellar wind properties consistent with either a main-sequence (MS) star or an asymptotic giant branch (AGB) star. We find that the synthetic X-ray luminosity for the MS case ($\sim 10^{19}\rm~erg~s^{-1}$) is far below the current X-ray limits. The predicted X-ray luminosity for the AGB case ($\sim 10^{34}\rm~erg~s^{-1}$), on the other hand, is compatible with the detected central X-ray sources, in particular the ones in Terzan 5 and NGC 6652. However, the probability of having an AGB star as the most-bound star around the putative IMBH is very low. Our study strongly suggests that it is very challenging to detect the accretion-induced X-ray emission from IMBHs, even if they were prevalent in present-day GCs.

Telescope pupil fragmentation from spiders generates specific aberrations observed at various telescopes and expected on the large telescopes under construction. This so-called island effect induces differential pistons, tips and tilts on the pupil petals, deforming the instrumental PSF, and is one of the main limitations to the detection of exoplanets with high-contrast imaging. These aberrations have different origins such as the low-wind effect or petaling errors in the adaptive-optics reconstruction. In this paper, we propose to alleviate the impact of the aberrations induced by island effects on high-contrast imaging by adapting the coronagraph design in order to increase its robustness to petal-level aberrations. Following a method first developed for errors due to primary mirror segmentation (segment phasing errors, missing segments...), we develop and test Redundant Apodized Pupils (RAP), i.e. apodizers designed at the petal-scale, then duplicated and rotated to mimic the pupil petal geometry. We apply this concept to the ELT architecture, made of six identical petals, to yield a 10^-6 contrast in a dark region from 8 to 40lambda/D. Both amplitude and phase apodizers proposed in this paper are robust to differential pistons between petals, with minimal degradation to their coronagraphic PSFs and contrast levels. In addition, they are also more robust to petal-level tip-tilt errors than apodizers designed for the whole pupil, with which the limit of contrast of 10^-6 in the coronagraph dark zone is achieved for constraints up to 2 rad RMS of these petal-level modes. The RAP concept proves its robustness to island effects (low-wind effect and post-adaptive optics petaling), with an application to the ELT architecture. It can also be considered for other 8- to 30-meter class ground-based units such as VLT/SPHERE, Subaru/SCExAO, GMT/GMagAO-X, or TMT/PSI.

Recent interstellar detections include a significant number of molecules containing vinyl (C2H3) and ethyl (C2H5) groups in their structure. For several of these molecules, there is not a clear experimental or theoretical evidence that support their formation from simpler precursors. We carried out a systematic search of viable reactions starting from closed shell hydrocarbons containing two carbon atoms (ethane, C2H6; ethylene, C2H4; and acetylene, C2H2) with the goal of determining viable chemical routes for the formation of vinyl and ethyl molecules on top of interstellar dust grains. Our results show that both H and OH radicals are key in converting acetylene and ethylene into more complex radicals that are susceptible to continue reacting and forming interstellar complex organic molecules. The relevant reactions, for example OH additions, present rate constants above 10$^{1}$ s$^{-1}$ that are likely competitive with OH diffusion on grains. Similarly, H atom addition to acetylene and ethylene is a very fast process with rate constants above 10$^{4}$ s$^{-1}$ in all cases, and greatly enhanced by quantum tunneling. Hydrogen abstraction reactions are less relevant, but may play a role in specific cases involving the OH radical. Reactions with other radicals NH2, CH3 are likely to have a much lesser impact in the chemistry of ethyl and vinyl bearing molecules.

The spin precession of binary black holes (BBHs) that originate from isolated high-mass binary stars is determined by the interplay of phenomena such as tides, winds, accretion, common-envelope evolution, natal kicks, and stellar core-envelope coupling. In previous work, we identified regions of the parameter space that may produce BBHs with large misalignments from natal kicks and high spin magnitudes from three mechanisms - tides, accretion, or inheritance via minimal core-envelope coupling. Here, we explore the spin precession of such BBHs using five parameters that describe the amplitude and frequency with which the orbital angular momentum precesses and nutates about the total angular momentum, modulating the gravitational-wave emission. Precession is generally possible for sufficiently strong natal kicks provided at least one of the black holes is spinning. Nutation is a consequence of spin-spin coupling and depends on the three spin-up mechanisms. Tidal synchronization can leave a distinct correlation between the aligned effective spin and the nutation frequency, but does not produce large nutations. When a black hole accretes $\gtrsim 20\%$ of its companion's envelope, the precession frequency and amplitude are large. A much smaller amount of accretion, e.g., $\approx 2\%$, is needed to provide a large precession frequency and amplitude when the accretor is a Wolf-Rayet (WR) star. The inheritance of high natal WR spins ($\gtrsim 5\%$ of their maximum breakup value) via minimal core-envelope coupling is the most promising mechanism for producing nutating BBHs, implying that a measurement of nutation from gravitational-wave observations may suggest isolated-binary origin with minimal core-envelope coupling.

We extend here a previous investigation on the characteristics of Galactic carbon stars using more accurate EDR3 astrometry measurements. Based on a much larger statistics, we confirm that N- and SC-type carbon stars share a very similar luminosity function, while the luminosities of J-type stars (Mbol) are fainter by half a magnitude on average. R-hot type carbon stars have luminosities throughout the RGB, which favours the hypothesis of an external origin for their carbon enhancement. Moreover, the kinematic properties of a significant fraction of the R-hot stars are compatible with the thick-disc population, in contrast with that of N- and SC-type stars, which would belong mostly to the thin disk. We also derive the luminosity function of a large number of Galactic extrinsic and intrinsic (O-rich) S stars and show that the luminosities of the latter are typically higher than the predicted onset of the third dredge-up during the AGB for solar metallicity. This result is consistent with these stars being genuine thermally pulsing AGB stars. On the other hand, using the so-called Gaia-2MASS diagram, we show that the overwhelming majority of the carbon stars identified in the LAMOST survey as AGB stars are probably R-hot and/or CH-type stars. Finally, we report the identification of 2660 new carbon stars candidates that we identified through their 2MASS photometry, their Gaia astrometry, and their location in the Gaia-2MASS diagram.

Here we point out that an observation of Ultra-High Energy Cosmic Ray (UHECR) photons, "GZK photons", could provide an upper limit on the level of the Extra-Galactic Radio Background, depending on the level of UHECR proton primaries (to be determined after a few years of data taking by the Pierre Auger Observatory upgrade AugerPrime). We also update our 2005 prediction of the range of GZK photon fluxes expected from proton primaries.

We report the discovery of high velocity candidates among RR~Lyrae stars found in the Milky Way halo. We identified 9 RR~Lyrae stars with Galactocentric velocities exceeding the local escape velocity based on the assumed Galaxy potential. Based on close examination of their orbits', we ruled out their ejection location in the Milky Way disk and bulge. The spatial distribution revealed that seven out of 9 pulsators overlap with the position of the Sagittarius stellar stream. Two out of these seven RR~Lyrae stars can be tentatively linked to the Sagittarius dwarf spheroidal galaxy on the basis of their orbits. Focusing on the high-velocity tail of the RR~Lyrae velocity distribution we estimate the escape velocity in the Solar neighborhood to be $v_{\rm esc}=512^{+94}_{-37}$\,km\,s$^{-1}$~($4$ to $12$\,kpc), and beyond the Solar neighborhood as $v_{\rm esc}=436^{+44}_{-22}$\,km\,s$^{-1}$~and $v_{\rm esc}=393^{+53}_{-26}$\,km\,s$^{-1}$~(for distances between $12$ to $20$\,kpc and $20$ to $28$\,kpc), respectively. We utilized three escape velocity estimates together with the local circular velocity to estimate the Milky Way mass. The resulting measurement $M_{\rm 200}=0.83^{+0.29}_{-0.16} \cdot 10^{12}$\,M$_{\odot}$ falls on the lower end of the current Milky Way mass estimates, but once corrected for the likely bias in the escape velocity (approximately $10$ percent increase of the escape velocity), our mass estimate yields $M_{\rm 200}=1.26^{+0.40}_{-0.22} \cdot 10^{12}$\,M$_{\odot}$, which is in agreement with estimates based on different diagnostics of the Milky Way mass. The MW mass within $20$\,kpc then corresponds to $M_{\rm MW} \left(r < 20\,\text{kpc} \right)=1.9^{+0.2}_{-0.1} \times 10^{11}$\,M$_{\odot}$ without correction for bias, and $M_{\rm MW} \left(r < 20\,\text{kpc} \right)=2.1^{+0.2}_{-0.1} \times 10^{11}$\,M$_{\odot}$ corrected for a likely offset in escape velocities.

Context. HD 95086 is a young nearby Solar System analog hosting a giant exoplanet orbiting at 57 au from the star between an inner and outer debris belt. The existence of additional planets has been suggested as the mechanism that maintains the broad cavity between the two belts. Aims. We present a dedicated monitoring of HD 95086 with the VLT/SPHERE instrument to refine the orbital and atmospheric properties of HD 95086 b, and to search for additional planets in this system. Methods. SPHERE observations, spread over ten epochs from 2015 to 2019 and including five new datasets, were used. Combined with archival observations, from VLT/NaCo (2012-2013) and Gemini/GPI (2013-2016), the extended set of astrometric measurements allowed us to refine the orbital properties of HD 95086 b. We also investigated the spectral properties and the presence of a circumplanetary disk around HD 95086 b by using the special fitting tool exploring the diversity of several atmospheric models. In addition, we improved our detection limits in order to search for a putative planet c via the K-Stacker algorithm. Results. We extracted for the first time the JH low-resolution spectrum of HD 95086 b by stacking the six best epochs, and confirm its very red spectral energy distribution. Combined with additional datasets from GPI and NaCo, our analysis indicates that this very red color can be explained by the presence of a circumplanetary disk around planet b, with a range of high-temperature solutions (1400-1600 K) and significant extinction (Av > 10 mag), or by a super-solar metallicity atmosphere with lower temperatures (800-1300 K), and small to medium amount of extinction (Av < 10 mag). We do not find any robust candidates for planet c, but give updated constraints on its potential mass and location.

Searching for periodic non-accelerated signals in presence of ideal white noise using the fully phase-coherent Fast Folding Algorithm (FFA) is theoretically established as a more sensitive search method than the Fast Fourier Transform (FFT) search with incoherent harmonic summing. In this paper, we present a comparison of the performance of an FFA search implementation using RIPTIDE and an FFT search implementation using PRESTO, over a range of signal parameters with white noise and with real telescope noise from the GHRSS survey with the uGMRT. We find that FFA search with appropriate de-reddening of time series, performs better than FFT search with spectral whitening for long period pulsars in real GHRSS noise conditions. We describe an FFA search pipeline implemented for the GHRSS survey looking for pulsars over a period range of 0.1 s to 100 s and up to dispersion measure of 500 pc cm$^{-3}$. We processed GHRSS survey data covering $\sim$ 1500 degree$^2$ of the sky with this pipeline. We re-detected 43 known pulsars with better signal-to-noise in the FFA search than in the FFT search. We also report discovery of two new pulsars including a long period pulsar having a short duty-cycle with this FFA search pipeline. The population of long period pulsars with periods of several seconds or higher can help to constrain the pulsar death-line.

Large neutrino detectors like IceCube monitor for core-collapse supernovae using low energy (MeV) neutrinos, with a reach to a supernova neutrino burst to the Magellanic Cloud. However, some models predict the emission of high energy neutrinos (GeV-TeV) from core-collapse supernovae through the interaction of ejecta with circumstellar material and (TeV-PeV) through choked jets. In this paper, we explore the detection horizon of IceCube for core-collapse supernovae using high-energy neutrinos from these models. We examine the potential of two high-energy neutrino data samples from IceCube, one that performs best in the northern sky and one that has better sensitivity in the southern sky. We demonstrate that by using high-energy neutrinos from core-collapse supernovae, the detection reach can be extended to the Mpc range, far beyond what is accessible through low-energy neutrinos. Looking ahead to IceCube-Gen2, this reach will be extended considerably.

The mechanisms that maintain turbulence in the interstellar medium (ISM) are still not identified. This work investigates how we can distinguish between two fundamental driving mechanisms: the accumulated effect of stellar feedback versus the energy injection from Galactic scales. We perform a series of numerical simulations describing a stratified star forming ISM subject to self-consistent stellar feedback. Large scale external turbulent driving of various intensities is added to mimic galactic driving mechanisms. We analyse the resulting column density maps with a technique called Multi-scale non-Gaussian segmentation that separates the coherent structures and the Gaussian background. This effectively discriminates between the various simulations and is a promising method to understand the ISM structure. In particular the power spectrum of the coherent structures flattens above 60 pc when turbulence is driven only by stellar feedback. When large-scale driving is applied, the turn-over shifts to larger scales. A systematic comparison with the Large Magellanic Cloud (LMC) is then performed. Only 1 out of 25 regions has a coherent power spectrum which is consistent with the feedback-only simulation. A detailed study of the turn-over scale leads us to conclude that regular stellar feedback is not enough to explain the observed ISM structure on scales larger than 60 pc. Extreme feedback in the form of supergiant shells likely plays an important role but cannot explain all the regions of the LMC. If we assume ISM structure is generated by turbulence, another large scale driving mechanism is needed to explain the entirety of the observations.

In gravitational microlensing formalism and for modeling binary light curves, the key step is solving the binary lens equation. Currently, a combination of the Newton's and Laguerre's methods which was first introduced by Skowron \& Gould (SG) is used while modeling binary light curves. In this paper, we first introduce a fast root-finding algorithm for univariate polynomials based on the Aberth-Ehrlich (AE) method which was first developed in 1967 as an improvement over the Newton's method. AE algorithm has proven to be much faster than Newton's, Laguerre's and Durand-Kerner methods and unlike other root-finding algorithms, it is able to produce all the roots simultaneously. After improving the basic AE algorithm and discussing its properties, we will optimize it for solving binary lens equations, which are fifth degree polynomials with complex coefficients. Our method is about $1.8$ to $2.0$ times faster than the SG algorithm. Since, for calculating magnification factors for point-like or finite source stars, it is necessary to solve the binary lens equation and find the positions of the produced images in the image plane first, this new method will improve the speed and accuracy of binary microlensing modeling.

The effect of large magnetic Prandtl number Pm (the ratio of viscosity to resistivity) on the turbulent transport and energetics of the magnetorotational instability (MRI) is poorly understood, despite the realization of this regime in astrophysical environments as disparate as discs from binary neutron star mergers, the inner regions of low mass X-ray binaries and active galactic nuclei, and the interiors of protoneutron stars. We investigate the MRI dynamo and associated turbulence in the regime $\text{Pm}>1$ by carrying out fully compressible, 3D MHD shearing box simulations using the finite-volume code \textsc{PLUTO}, focusing mostly on the case of Keplerian shear relevant to accretion discs. We find that when the magnetic Reynolds number is kept fixed, the turbulent transport (as measured by the stress-to-thermal-pressure ratio $\alpha$) scales with the magnetic Prandtl number as $\alpha \sim \text{Pm}^{\delta}$, with $\delta \sim 0.5-0.7$ up to $\text{Pm} \sim 128$. However, this scaling weakens as the magnetic Reynolds number is increased. Importantly, compared to previous studies, we find a new effect at very large Pm -- the turbulent energy and stress begin to plateau, no longer depending on ${\rm Pm}$. To understand these results we have carried out a detailed analysis of the turbulent dynamics in Fourier space, focusing on the effect increasing Pm has on the transverse cascade -- a key non-linear process induced by the disc shear flow that is responsible for the sustenance of MRI turbulence. Finally, we find that the scaling of turbulent transport with Pm is sensitive to the box vertical-to-radial aspect ratio, as well as to the background shear: tall boxes exhibit weaker scaling compared to cubic boxes, while MRI turbulence in sub-Keplerian shear flows (characteristic of protoneutron stars) exhibits stronger scaling than it does in Keplerian discs.

How filaments form and erupt are topics about which solar researchers have wondered since more than a century and that are still open to debate. We present observations of a filament formation, its failed eruption, and the associated flare (SOL2019-05-09T05:51) that occurred in active region (AR) 12740 using data from SDO, STEREO-A, IRIS, and NSO/GONG. AR 12740 was a decaying region formed by a very disperse following polarity and a strong leading spot, surrounded by a highly dynamic zone where moving magnetic features (MMFs) were seen constantly diverging from the spot. Our analysis indicates that the filament was formed by the convergence of fibrils at a location where magnetic flux cancellation was observed. Furthermore, we conclude that its destabilization was also related to flux cancellation associated to the constant shuffling of the MMFs. A two-ribbon flare occurred associated to the filament eruption; however, because the large-scale magnetic configuration of the AR was quadrupolar, two additional flare ribbons developed far from the two main ones. We model the magnetic configuration of the AR using a force-free field approach at the AR scale size. This local model is complemented by a global potential-field source-surface one. Based on the local model, we propose a scenario in which the filament failed eruption and flare are due to two reconnection processes, one occurring below the erupting filament, leading to the two-ribbon flare, and another one above it between the filament flux-rope configuration and the large-scale closed loops. Our computation of the reconnected magnetic flux added to the erupting flux rope, compared to that of the large-scale field overlying it, lets us conclude that the latter was large enough to prevent the filament eruption. A similar conjecture can be drawn from the computation of the magnetic tension derived from the global field model.

Many astrophysical environments, from star clusters and globular clusters to the disks of Active Galactic Nuclei, are characterized by frequent interactions between stars and the compact objects that they leave behind. Here, using a suite of $3-D$ hydrodynamics simulations, we explore the outcome of close interactions between $1M_{\odot}$ stars and binary black holes (BBHs) in the gravitational wave regime, resulting in a tidal disruption event (TDE) or a pure scattering, focusing on the accretion rates, the back reaction on the BH binary orbital parameters and the increase in the binary BH effective spin. We find that TDEs can make a significant impact on the binary orbit, which is often different from that of pure scattering. Binaries experiencing a prograde (retrograde) TDE tend to be widened (hardened) by up to $\simeq 20\%$. Initially circular binaries become more eccentric by $\lesssim 10\%$ by a prograde or retrograde TDE, whereas the eccentricity of initially eccentric binaries increases (decreases) by a retrograde (prograde) TDE by $\lesssim 5\%$. Overall a single TDE can generally result in changes of the gravitational wave-driven merger time scale by order unity. The accretion rates of both black holes are very highly super-Eddington, showing modulations (preferentially for retrograde TDEs) on a time scale of the orbital period, which can be a characteristic feature of BBH-driven TDEs. Prograde TDEs result in the effective spin parameter $\chi$ to vary by $\lesssim 0.02$ while $\chi\gtrsim -0.005$ for retrograde TDEs.

Objects from the Sixth catalog of orbits of visual binary stars (ORB6) are investigated to validate Gaia EDR3 parallaxes and provide mass estimates for the respected systems. We show that 2/3 of binaries with 0.2 -- 0.5 arcsec separation are left without parallax solution in EDR3. A special attention is paid to 521 pairs with parallax known separately for both components. 16 entries are deemed optical pairs. At once we give examples of solid binary stars with large discrepancy of reported parallaxes, which are underestimated at least by a factor of 3 for stars with large RUWE. Parallaxes are needed to estimate stellar masses. Since nearly 30\% of ORB6 entries lack full 5 or 6-parameter solution in EDR3, we attempt to enrich the astrometric data. Distant companions of ORB6 entries are revealed in EDR3 by analysis of stellar proper motion and Hipparcos parallaxes. In certain cases intrinsic EDR3 parallaxes of binary components are less reliable than of the outer companions. Gaia DR2, TGAS and Hipparcos parallaxes are used when EDR3 data is unavailable. Synthetic mass-luminosity relation in G band for main sequence stars is obtained to provide mass estimates along with dynamical mass calculated via Kepler's Third Law.

We present photometric and spectroscopic data of the unusual interacting supernova (SN) 2021foa. It rose to an absolute magnitude peak of $M_r=-18$ mag in 20 days. The initial light curve decline shows some luminosity fluctuations before a long-lasting flattening. A faint source ($M_r\sim -14$ mag) was detected in the weeks preceding the main event, showing a slow-rising luminosity trend. The $r$-band absolute light curve is very similar to those of SN 2009ip-like events, with a faint and shorter duration brightening (`Event A') followed by a much brighter peak (`Event B'). The early spectra of SN 2021foa show a blue continuum with narrow ($v_{FWHM}\sim$400 km s$^{-1}$) H emission lines, that, two weeks later, reveal a complex profile, with a narrow P Cygni on top of an intermediate-width ($v_{FWHM}\sim$2700 km s$^{-1}$) component. At +12 days metal lines in emission appear, while \Hei lines become very strong, with \Hei~$\lambda$5876 reaching half of the \Ha luminosity, much higher than in previous SN 2009ip-like objects. We propose SN 2021foa to be a transitional event between the H-rich SN 2009ip-like SNe and the He-rich Type Ibn SNe.

The radiative loss interpretation for the broken power-law spectra of blazars is often questioned since the difference between the indices does not support this inference. Using the blazar Mkn 421 as a case study, we performed a detailed analysis of its characteristic photon energy where the spectral index changes significantly. We used the observations of the source by Swift-XRT from 2008 to 2019 to identify the characteristic photon energy and the corresponding spectral indices. The spectra in the energy range 0.3-10.0 keV can be well fitted by a log parabola as well as a smooth broken power-law. From the smooth broken power-law spectral fit we show that the spectral indices before and after the characteristic photon energy are strongly anti-correlated. Further, the spectral curvature measured at the characteristic photon energy indicates an anti-correlation with the low energy spectral index while the high energy spectral index shows a positive correlation. These findings are at variance with a simple radiative loss interpretation for the characteristic photon energy, and alternative scenarios are thus discussed. Though these scenarios are in principle capable of reproducing the correlation results, they deviate significantly from the observed properties.

We present a study of the size--mass relation for local post-starburst (PSB) galaxies at $z\lesssim0.33$ selected from the Sloan Digital Sky Survey Data Release 8. We find that PSB galaxies with stellar mass ($M_*$) at $10^9~M_{\odot}<M_*<10^{12}~M_{\odot}$ have their galaxy size smaller than or comparable with those of quiescent galaxies (QGs). After controlling redshift and stellar mass, the sizes of PSBs are $\sim 13\%$ smaller on average than those of QGs, such differences become larger and significant towards the low-$M_*$ end, especially at $10^{9.5}~M_{\odot} \lesssim M_*\lesssim 10^{10.5}~M_{\odot}$ where PSBs can be on average $\sim 19\%$ smaller than QGs. In comparison with predictions of possible PSB evolutionary pathways from cosmological simulations, we suggest that a fast quenching of star formation following a short-lived starburst event (might be induced by major merger) should be the dominated pathway of our PSB sample. Furthermore, by cross-matching with group catalogs, we confirm that local PSBs at $M_*\lesssim10^{10}~M_{\odot}$ are more clustered than more massive ones. PSBs resided in groups are found to be slightly larger in galaxy size and more disk-like compared to field PSBs, which is qualitatively consistent with and thus hints the environment-driven fast quenching pathway for group PSBs. Taken together, our results support multiple evolutionary pathways for local PSB galaxies: while massive PSBs are thought of as products of fast quenching following a major merger-induced starburst, environment-induced fast quenching should play a role in the evolution of less massive PSBs, especially at $M_*\lesssim 10^{10}~M_{\odot}$.

New light fundamental fields are natural candidates for all or a fraction of dark matter. Self-gravitating structures of such fields might be common objects in the universe, and could comprise even galactic haloes. These structures would interact gravitationally with black holes, process of the utmost importance, since it dictates their lifetime, the black hole motion and possible gravitational radiation emission. Here, we study the dynamics of a black hole piercing through a much larger fully relativistic boson star, made of a complex minimally coupled massive scalar without self-interactions. As the black hole pierces through the bosonic structure, it is slowed down by accretion and dynamical friction, giving rise to gravitational wave emission. Since we are interested in studying the interaction with large and heavy scalar structures, we consider mass ratios up to $q\sim 10$ and length ratios ${\cal L} \sim 62$. Somewhat surprisingly, for all our simulations, the black hole accretes more than 95% of the boson star material, even if an initially small black hole collides with large velocity. This is a consequence of an extreme "tidal capture" process, which binds the black hole and the boson star together, for these mass ratios. We find evidence of a "gravitational atom" left behind as a product of the process.

We study neutrinos gravitationally scattered off a rotating supermassive black hole which is surrounded by a thin accretion disk with a realistic magnetic field. Neutrinos are supposed to be Dirac particles having a nonzero magnetic moment. Neutrinos, while being scattered, move along arbitrary trajectories not restricted by the equatorial plane. We exactly account for the influence of both gravity and magnetic field on the neutrino motion and its spin evolution. We find the measurable fluxes of outgoing neutrinos taking into account the neutrino spin precession in the external field in curved spacetime. These fluxes turn out to be significantly suppressed for some parameters of the system. Finally, we discuss the possibility to observe the predicted phenomena for core-collapsing supernova neutrinos in our Galaxy.

Two of the most fundamental problems at the nexus of Einstein's classical General Relativity (GR) and Quantum Field Theory (QFT) are: (1) complete gravitational collapse, presumed in classical GR to lead to a Black Hole (BH) horizon and interior singularity, which generate a number of paradoxes for quantum theory; and (2) the origin and magnitude of the cosmological dark energy driving the accelerated expansion of the Universe. In this Snowmass white paper it is proposed that these twin puzzles on disparate scales are related, and that their resolution depends upon taking full account of the conformal anomaly of quantum matter in gravitational fields. The topological term in the anomaly leads naturally to the introduction of an abelian $3$-form gauge field, whose field strength can account for a variable gravitational condensate with the vacuum dark energy equation of state $p=-\rho$, the magnitude of which depends upon macroscopic boundary conditions rather than ultraviolet cutoffs. The resulting Effective Field Theory (EFT) of low energy quantum gravity results in a non-singular `BH' interior and physical surface replacing the classical event horizon, which is a gravitational condensate star free of any information paradox. The development and predictions of this EFT can be tested by gravitational waves and observational cosmology in the coming decade.

Equation of states (EOS) of the spin-polarized nuclear matter (NM) is studied within the Hartree-Fock (HF) formalism using the realistic density dependent nucleon-nucleon interaction. With a nonzero fraction $\Delta$ of spin-polarized baryons in NM, the spin- and spin-isospin dependent parts of the HF energy density give rise to the \emph{spin symmetry} energy that behaves in about the same manner as the \emph{isospin symmetry} energy, widely discussed in literature as the nuclear symmetry energy. The present HF study shows a strong correlation between the spin symmetry energy and nuclear symmetry energy over the whole range of baryon densities. The important contribution of the spin symmetry energy to the EOS of the spin-polarized NM is found to be comparable with that of the nuclear symmetry energy to the EOS of the isospin-polarized or asymmetric (neutron-rich) NM. Based on the HF energy density, the EOS of the spin-polarized ($\beta$-stable) np$e\mu$ matter is obtained for the determination of the macroscopic properties of neutron star (NS). A realistic density dependence of the spin-polarized fraction $\Delta$ have been suggested to explore the impact of the spin symmetry energy to the gravitational mass $M$ and radius $R$, as well as the tidal deformability of NS. Given the empirical constrains inferred from a coherent Bayesian analysis of gravitational wave signals of the NS merger GW170817 and the observed masses of the heaviest pulsars, the strong impacts of the spin symmetry energy $W$, nuclear symmetry energy $S$, and nuclear incompressibility $K$ to the EOS of nucleonic matter in magnetar were revealed.

Proportional electroluminescence (EL) in noble gases is the physical effect routinely used in two-phase (liquid-gas) detectors for dark matter searches to record the primary ionization signal in the gas phase induced by particle scattering in the liquid phase. In this work, the time properties of visible-light EL in two-phase argon detectors have for the first time been systematically studied. In particular, two unusual slow components in the EL signal, with time constants of about 4-5 $\mu$s and 50 $\mu$s, were observed. Their puzzling property is that their contributions and time constants increase with electric field, which is not expected in any of the known mechanisms of photon and electron emission in two-phase media. In addition, a specific threshold behavior of the slow components was revealed: they emerged at a threshold in reduced electric field of about 5 Td regardless of the gas phase density, which is 1 Td above the onset of standard (excimer) EL. It is shown that this threshold is related to higher atomic excited states Ar$^{*}(3p^{5}4p)$. An unexpected temperature dependence of slow components was also observed: their contribution decreased with temperature, practically disappearing at room temperature. We show that the puzzling properties of slow components can be explained in the framework of hypothesis that these are produced in the charge signal itself due to trapping of drifting electrons on metastable negative argon ions.

Dielectric axion haloscopes, such as the \mbox{{\sc Madmax}} experiment, are promising concepts for the direct search for dark matter axions. A reliable simulation is a fundamental requirement for the successful realisation of the experiments. Due to the complexity of the simulations, the demands on computing resources can quickly become prohibitive. In this paper, we show for the first time that modern deep learning techniques can be applied to aid the simulation and optimisation of dielectric haloscopes.

We investigate a possible depiction of the famous SN 1054 event in specially minted coins produced in the Eastern Roman Empire in 1054 A.D. On these coins, we investigate if the head of the Emperor, Constantine IX, might represent the Sun with a bright 'star' on either side - Venus in the east and SN 1054 in the west, perhaps also representing the newly split Christian churches. We explore the idea that the eastern star represents the stable and well-known Venus and the Eastern Orthodox Church, while the western star represents the short-lived 'new star' and the 'fading' Western Catholic church. We examined 36 coins of this rare Constantine IX Class IV batch. While no exact date could be associated to any of these coins, they most likely were minted during the last six months of Constantine IX's rule in 1054. We hypothesise that the stance of the church concerning the order of the Universe, as well as the chaos surrounding the Great Schism, played a crucial role in stopping the official reporting of an obvious event in the sky, yet a dangerous omen. A temporal coincidence of all these events could be a reasonable explanation as well.