Sazuna/UAT_keywords huggingface dataset:
The SUPERCOLD-CGM Survey. I. Probing the Extended CO(4-3) Emission of the Circumgalactic Medium in a Sample of 10 Enormous Lyα Nebulae at z ∼ 2. To understand how massive galaxies at high z coevolve with enormous reservoirs of halo gas, it is essential to study the coldest phase of the circumgalactic medium (CGM), which directly relates to stellar growth. The SUPERCOLD-CGM survey is the first statistical survey of cold molecular gas on CGM scales. We present Atacama Large Millimeter Array and Atacama Compact Array observations of CO(4-3) and continuum emission from 10 enormous Lyα nebulae (ELANe) around ultraluminous type I quasi-stellar objects (QSOs) at z ~ 2. We detect CO(4-3) in 100% of our targets, with 60% showing extended CO on scales of 15-100 kpc. Q1228+3128 reveals the most extended CO(4-3) reservoir of ~100 kpc and is the only radio-loud target in our sample. The CO reservoir is located along the radio axis, which could indicate a link between the inner radio jet and cold halo gas. For the other five radio-quiet ELANe, four of them show extended CO(4-3) predominantly in the direction of their companions. These extended CO(4-3) reservoirs identify enrichment of the CGM and may potentially contribute to widespread star formation. However, there is no evidence from CO(4-3) for diffuse molecular gas spread across the full extent of the Lyα nebulae. One target in our sample (Q0107) shows significant evidence for a massive CO disk associated with the QSO. Moreover, 70% of our QSO fields contain at least one CO companion, two of which reveal extended CO emission outside the ELANe. Our results provide insight into roles of both the cold CGM and companions in driving the early evolution of massive galaxies.

Keywords: Radio astronomy, Galaxy evolution, Circumgalactic medium
Backward Population Synthesis: Mapping the Evolutionary History of Gravitational-wave Progenitors. One promising way to extract information about stellar astrophysics from a gravitational-wave catalog is to compare the catalog to the outputs of stellar population synthesis modeling with varying physical assumptions. The parameter space of physical assumptions in population synthesis is high-dimensional and the choice of parameters that best represents the evolution of a binary system may depend in an as-yet-to-be-determined way on the system's properties. Here we propose a pipeline to simultaneously infer zero-age main-sequence properties and population synthesis parameter settings controlling modeled binary evolution from individual gravitational-wave observations of merging compact binaries. Our pipeline can efficiently explore the high-dimensional space of population synthesis settings and progenitor system properties for each system in a catalog of gravitational-wave observations. We apply our pipeline to observations in the third LIGO-Virgo Gravitational-Wave Transient Catalog. We showcase the effectiveness of this pipeline with a detailed study of the progenitor properties and population synthesis settings that produce mergers like the observed GW150914. Our pipeline permits a measurement of the variation of population synthesis parameter settings with binary properties, if any; we illustrate the possibility of such capability by presenting inferences for the recent GWTC-3 transient catalog that suggest that the stable mass transfer efficiency parameter may vary with primary black hole mass.

Keywords: Binary stars, Astrostatistics, Gravitational wave sources, Gravitational wave astronomy, Gravitational waves, Markov chain Monte Carlo, Algorithms
Synthetic Population of Binary Cepheids. II. The Effect of Companion Light on the Extragalactic Distance Scale. Because of their period-luminosity relation (PLR), classical Cepheids play a key role in the calibration of the extragalactic distance scale and the determination of the Hubble-Lemaître constant H 0. Recent findings show that the majority of classical Cepheids should be in binary or multiple systems, which might undermine their accuracy, as the extra-and unaccounted for-light from the companions of Cepheids causes a shift in the PLR. We quantify this shift using synthetic populations of binary Cepheids that we developed for this purpose, as described in Paper I of this series. We find that while all PLRs are shifted toward brighter values due to the excess light from the companions, the bias in the relative distance modulus between two galaxies hosting binary Cepheids can be either positive or negative, depending on the percentage of binary Cepheids in them. If the binarity percentage in the two galaxies is similar, the effect of binarity is canceled. Otherwise, it introduces a shift in the distance modulus of the order of millimagnitudes in the near-infrared passbands and Wesenheit indices, and tens of millimagnitudes in the visual domain; its exact value depends on the variant of the synthetic population (a unique combination of metallicity, star formation history, shape and location of the instability strip, and initial parameter distributions). Such shifts in the distance moduli to Type Ia supernova host galaxies introduce an additional statistical error on H 0, which however does not prevent measuring H 0 with a precision of 1%.

Keywords: Small Magellanic Cloud, Large Magellanic Cloud, Cepheid distance, Delta Cepheid variable stars, Detached binary stars, Milky Way Galaxy, Astronomical simulations
Confinedness of an X3.1-class Solar Flare Occurred in NOAA 12192: Analysis from Multi-instrument Observations. The nonassociation of coronal mass ejections with high energetic flares is sparse. For this reason, the magnetic conditions required for the confinedness of major flares is a topic of active research. Using multi-instrument observations, we investigated the evolution and effects of confinedness in an X3.1 flare, which occurred in active region (AR) 12192. The decrease of net fluxes in the brightening regions near the footpoints of the multisigmoidal AR in the photosphere and chromosphere, indicative of flux cancellation favoring tether-cutting reconnection (TCR), is observed using the magnetic field observations of HMI/SDO and SOT/Hinode, respectively. The analysis of spectropolarimetric data obtained by the Interferometric Bidimensional Spectrometer over the brightening regions suggests untwisting of field lines, which further supports TCR. Filaments near the polarity inversion line region, resulting from TCR of low-lying sheared loops, undergo merging and form an elongated filament. The temperature and density differences between the footpoints of the merged filament, revealed by DEM analysis, cause streaming and counterstreaming of the plasma flow along the filament and unload at its footpoints with an average velocity of ≈40 km s-1. This results in a decrease of the mass of the filament (density decreased by &gt;50%), leading to its rise and expansion outward. However, due to strong strapping flux, the filament separates itself instead of erupting. Further, the evolution of nonpotential parameters describes the characteristics of confinedness of the flare. Our study suggests that the sigmoid-filament system exhibits upward catastrophe due to mass unloading but gets suppressed by strong confinement of the external poloidal field.

Keywords: Solar active region magnetic fields, Solar flares, Solar active region filaments, Solar active regions, Solar activity
3D Radiation-hydrodynamic Simulations Resolving Interior of Rapidly Accreting Primordial Protostar. Direct collapse of supermassive stars is a possible pathway to form supermassive black hole seeds at high redshifts. Whereas previous three-dimensional (3D) simulations demonstrate that supermassive stars form via rapid mass accretion, those resolving the stellar interior have been limited. Here, we report 3D radiation-hydrodynamic (RHD) simulations following the evolution of rapidly accreting protostars resolving the stellar interior. We use an adaptive mesh refinement code with our newly developed RHD solver employing an explicit M1 closure method. We follow the early evolution until the stellar mass reaches ~10 M ⊙ from two different initial configurations of spherical and turbulent clouds. We demonstrate that, in both cases, a swollen protostar whose radius is 100-1000 R ⊙ appears, as predicted by the stellar evolution calculations. Its effective temperature remains a few thousand Kelvin, and the radiative feedback by ionizing photons is too weak to disturb the accretion flow up to the epoch examined in this work. In the turbulent case, the protostar rotates rapidly at more than 0.4 times the Keplerian velocity owing to the angular momentum provided by the initial turbulence. The protostar approximates an oblate spheroid, and its equatorial radius is more than twice the polar radius. Our results suggest that we need to consider the rapid stellar rotation to elucidate the realistic 3D protostellar evolution in the supermassive star formation.

Keywords: Early universe, Supermassive black holes, Star formation
Crustal Failure as a Tool to Probe Hybrid Stars. It is currently unknown if neutron stars (NSs) are composed of nucleons only or are hybrid stars, i.e., in addition to nucleonic crusts and outer cores, they also possess quark cores. Quantum chromodynamics allows for such a possibility, but accurate calculations relevant for compact stars are still elusive. Here we investigate some crust-breaking aspects of hybrid stars. We show that the crust-breaking frequency and maximum fiducial ellipticity are sensitive to the quark-hadron density jump and equation of state stiffness. Remarkably, the crust-breaking frequency related to static tides scales linearly with the mass of the star (for a given companion mass), and its slope encompasses information about the microphysics of the star. However, for precise crust-breaking frequency predictions, relativistic corrections to Kepler's third law and the Newtonian tidal field should not be ignored. When a liquid quark core touches an elastic hadronic phase (the result of a significant energy density jump), the maximum ellipticity can increase by around an order of magnitude when compared to a liquid quark core touching a liquid hadronic phase. That is relevant because it would increase the odds of detecting continuous gravitational waves from NSs. Our order-of-magnitude analysis also suggests that a given upper limit to the ellipticity (crust-breaking frequency) could have representatives in stars with either small or intermediate (large) energy density jumps. Therefore, when upper limits to the ellipticity for isolated stars are better constrained or electromagnetic radiation (e.g., gamma-ray precursors) is detected along with gravitational waves in inspiraling binary systems, they may help constrain some aspects of phase transitions in NSs.

Keywords: Neutron stars, Asteroseismology, General relativity
Nonparametric Model for the Equations of State of a Neutron Star from Deep Neural Network. It is of great interest to understand the equation of state (EOS) of the neutron star, whose core includes highly dense matter. However, there are large uncertainties in the theoretical predictions for the EOS of a neutron star. It is useful to develop a new framework, which is flexible enough to consider the systematic error in theoretical predictions and to use them as a best guess at the same time. We employ a deep neural network to perform a nonparametric fit of the EOS of a neutron star using currently available data. In this framework, the Gaussian process is applied to represent the EOSs and the training set data required to close physical solutions. Our model is constructed under the assumption that the true EOS of a neutron star is a perturbation of the relativistic mean-field model prediction. We fit the EOSs of neutron star using two different example data sets, which can satisfy the latest constraints from the massive neutron stars, NICER, and the gravitational wave of the binary neutron stars. Given our assumptions, we find that a maximum neutron star mass is ${2.38}_{-0.13}^{+0.15}{M}_{\odot }$ or ${2.41}_{-0.14}^{+0.15}{M}_{\odot }$ at the 95% confidence level from two different example data sets. It implies that the 1.4M ⊙ radius is ${12.31}_{-0.31}^{+0.29}$ or ${12.30}_{-0.37}^{+0.35}$ km. These results are consistent with results from previous studies using similar priors. It has demonstrated the recovery of the EOS of NS using a nonparametric model.

Keywords: Neutron stars, Nuclear physics, Neural networks
Binary Formation in a 100 μm Dark Massive Core. We report high-resolution ALMA observations toward a massive protostellar core C1-Sa (~30 M ⊙) in the Dragon infrared dark cloud. At the resolution of 140 au, the core fragments into two kernels (C1-Sa1 and C1-Sa2) with a projected separation of ~1400 au along the elongation of C1-Sa, consistent with a Jeans length scale of ~1100 au. Radiative transfer modeling using RADEX indicates that the protostellar kernel C1-Sa1 has a temperature of ~75 K and a mass of 0.55 M ⊙. C1-Sa1 also likely drives two bipolar outflows, one being parallel to the plane of the sky. C1-Sa2 is not detected in line emission and does not show any outflow activity but exhibits ortho-H2D+ and N2D+ emission in its vicinity; thus it is likely still starless. Assuming a 20 K temperature, C1-Sa2 has a mass of 1.6 M ⊙. At a higher resolution of 96 au, C1-Sa1 begins to show an irregular shape at the periphery, but no clear sign of multiple objects or disks. We suspect that C1-Sa1 hosts a tight binary with inclined disks and outflows. Currently, one member of the binary is actively accreting while the accretion in the other is significantly reduced. C1-Sa2 shows hints of fragmentation into two subkernels with similar masses, which requires further confirmation with higher sensitivity.

Keywords: Multiple stars, Binary stars, Infrared dark clouds, Star forming regions, Stellar jets, Massive stars, Molecular clouds, Astrochemistry, Star formation, Interstellar medium, Stellar accretion, Protostars
Merger Conditions of Population III Protostar Binaries. Massive close binary stars with extremely small separations have been observed, and they are possible progenitors of gravitational-wave sources. The evolution of massive binaries in the protostellar accretion stage is key to understanding their formation process. We, therefore, investigate how close the protostars, consisting of a high-density core and a vast low-density envelope, can approach each other but not coalesce. To investigate the coalescence conditions, we conduct smoothed particle hydrodynamics simulations following the evolution of equal-mass binaries with different initial separations. Since Population (Pop) I and III protostars have similar interior structures, we adopt a specific Pop III model with the mass and radius of 7.75 M ⊙ and 61.1 R ⊙ obtained by the stellar evolution calculations. Our results show that the binary separation decreases due to the transport of the orbital angular momentum to spin angular momentum. If the initial separation is less than about 80% of the sum of the protostellar radius, the binary coalesces in a time shorter than the tidal lock timescale. The mass loss up to the merging is ≲3%. After coalescence, the star rotates rapidly, and its interior structure is independent of the initial separation. We conclude that there must be some orbital shrinking mechanism after the protostars contract to enter the zero-age main-sequence stage.

Keywords: Close binary stars, Protostars, Population III stars
Searching for Dwarf Hα Emission-line Galaxies within Voids. I. Survey Methods and First Observations. The population density of dwarf galaxies in low-density voids is likely determined by the dark matter halo mass function and how galaxy formation proceeds in smaller halos. This depends on the nature of dark matter itself, making the dwarf galaxy population a tracer of its properties. While dwarfs have been found in smaller, closer voids, they have proven difficult to find in larger, more distant voids through magnitude-limited spectroscopic surveys. This is because these surveys detect an overwhelmingly large number of objects behind the voids that must be verified spectroscopically, making void surveys prohibitively inefficient and expensive in terms of large-telescope time. Narrowband imaging for emission lines such as Hα reduces the number of background objects, although the overall number remains large. If imaging is done through a filter set with overlapping transmission wings, then object redshift can be estimated from photometry alone. The precision possible is an order of magnitude greater than single-band photometry, with the caveat that the captured line must be identified through other means. Broadband photometry can be used to reject enough objects with emission of an unwanted type to make obtaining spectra of the remaining objects feasible. In this study, we present an Hα survey for dwarf galaxies with M  r ' fainter than -14 mag through the center 4.3 square degrees of the void FN8. Using Sloan $g^{\prime} ,r^{\prime} ,i^{\prime} $ photometry, we exclude enough [O II] and [O III] emitters that follow-up spectra of only a few dozen objects are required to statistically estimate the void population density.

Keywords: Dwarf galaxies, Voids, Mean matter density, Large-scale structure of the universe
High-energy Neutrino Emission Associated with Gravitational-wave Signals: Effects of Cocoon Photons and Constraints on Late-time Emission. We investigate prospects for the detection of high-energy neutrinos produced in the prolonged jets of short gamma-ray bursts (sGRBs). The X-ray light curves of sGRBs show extended emission components lasting for 100-1000 s, which are considered to be produced by prolonged engine activity. Jets produced by such activity should interact with photons in the cocoon formed by the propagation of the jet inside the ejecta of neutron star mergers. We calculate neutrino emission from jets produced by prolonged engine activity, taking account of the interaction between photons provided from the cocoon and cosmic rays accelerated in the jets. We find that IceCube-Gen2, a future neutrino telescope, with second-generation gravitational-wave detectors will probably be able to observe neutrino signals associated with gravitational waves with around 10 years of operation, regardless of the assumed value of the Lorentz factor of the jets. Neutrino observations may enable us to constrain the dissipation region of the jets. We apply this model to GRB 211211A, a peculiar long GRB whose origin may be a binary neutron star merger. Our model predicts that IceCube is unlikely to detect any associated neutrinos, but a few similar events will be able to put a meaningful constraint on the physical quantities of the prolonged engine activities.

Keywords: Neutron stars, Gamma-ray bursts, Neutrino astronomy, Gravitational wave astronomy, Particle astrophysics
The Young and the Wild: What Happens to Protoclusters Forming at Redshift z ≈ 4?. Using one of the largest volumes of the hydrodynamical cosmological simulation suit Magneticum, we study the evolution of protoclusters identified at redshift ≈ 4, with properties similar to the well-observed protocluster SPT2349-56. We identify 42 protoclusters in the simulation as massive and equally rich in substructures as observed, confirming that these observed structures can already be virialized. The dynamics of the internally fast-rotating member galaxies within these protoclusters resemble observations, merging rapidly to form the cores of the brightest cluster galaxies of the assembling clusters. Half of the gas reservoir of these structures is in a hot phase, with the metal enrichment at a very early stage. These systems show a good agreement with the observed amount of cold star-forming gas, largely enriched to solar values. We predict that some of the member galaxies are already quenched at z ≈ 4, rendering them undetectable through measurements of their gas reservoirs. Tracing the evolution of protoclusters reveals that none of the typical mass indicators at high redshift are good tracers to predict the present-day mass of the system. We find that none of the simulated protoclusters at z = 4.3 are among the top ten most massive clusters at redshift z = 0.2, with some barely reaching masses of M ≈ 2 × 1014  M ⊙. Although the average star formation and mass growth rates in the simulated galaxies match observations at high redshift reasonably well, the simulation fails to reproduce the extremely high total star formation rates within the observed protoclusters, indicating that the subgrid models are lacking the ability to reproduce a higher star formation efficiency (or lower depletion timescales).

Keywords: Galaxy clusters, Early universe, High-redshift galaxy clusters, Large-scale structure of the universe, Computational methods
JWST/NIRSpec Measurements of the Relationships between Nebular Emission-line Ratios and Stellar Mass at z   3-6. We analyze the rest-optical emission-line ratios of star-forming galaxies at 2.7 ≤ z &lt; 6.5 drawn from the Cosmic Evolution Early Release Science (CEERS) Survey and their relationships with stellar mass (M *). Our analysis includes both line ratios based on the [N II] λ6583 feature ([N II] λ6583/Hα, ([O III] λ5007/Hβ)/([N II] λ6583/Hα) (O3N2), and [N II] λ6583/[O II] λ3727) and those featuring α-elements ([O III] λ5007/Hβ, [O III] λ5007/[O II] λ3727 (O32), ([O III] λλ4959, 5007 + [O II] λ3727)/Hβ (R23), and [Ne III] λ3869/[O II] λ3727). Given the typical flux levels of [N II] λ6583 and [Ne III] λ3869, which are undetected in the majority of individual CEERS galaxies at 2.7 ≤ z &lt; 6.5, we construct composite spectra in bins of M * and redshift. Using these composite spectra, we compare the relationships between emission-line ratios and M * at 2.7 ≤ z &lt; 6.5 with those observed at lower redshift. While there is significant evolution toward higher excitation (e.g., higher [O III] λ5007/Hβ, O32, O3N2) and weaker nitrogen emission (e.g., lower [N II] λ6583/Hα and [N II] λ6583/[O II] λ3727) between z ~ 0 and z ~ 3, we find in most cases that there is no significant evolution in the relationship between line ratio and M * beyond z ~ 3. The [Ne III] λ3869/[O II] λ3727 ratio is anomalous in showing evidence for significant elevation at 4.0 ≤ z &lt; 6.5 at fixed mass, relative to z ~ 3.3. Collectively, however, our empirical results suggest no significant evolution in the mass-metallicity relationship at 2.7 ≤ z &lt; 6.5. Representative galaxy samples and metallicity calibrations based on existing and upcoming JWST/NIRSpec observations will be required to translate these empirical scaling relations into ones tracing chemical enrichment and gas cycling and to distinguish among descriptions of feedback in galaxy formation simulations at z &gt; 3.

Keywords: Galaxy formation, High-redshift galaxies, Galaxy evolution