Sazuna/UAT_keywords huggingface dataset:
New Constraint on the Tensor-to-scalar Ratio from the Planck and BICEP/Keck Array Data Using the Profile Likelihood. Motivated by the discrepancy between Bayesian and frequentist upper limits on the tensor-to-scalar ratio parameter r found by the SPIDER collaboration, we investigate whether a similar trend is also present in the latest Planck and BICEP/Keck Array data. We derive a new upper bound on r using the frequentist profile likelihood method. We vary all the relevant cosmological parameters of the ΛCDM model, as well as the nuisance parameters. Unlike the Bayesian analysis using Markov Chain Monte Carlo (MCMC), our analysis is independent of the choice of priors. Using Planck Public Release 4, BICEP/Keck Array 2018, Planck cosmic microwave background lensing, and baryon acoustic oscillation data, we find an upper limit of r &lt; 0.037 at 95% Confidence Level (C.L.), similar to the Bayesian MCMC result of r &lt; 0.038 for a flat prior on r and a conditioned Planck lowlEB covariance matrix.

Keywords: Cosmology, Cosmological parameters, Cosmic microwave background radiation, Cosmic inflation
Discovery of a Radio-loud Narrow-line Seyfert 1 Galaxy at z = 0.9 Reddened with a Strong 2175 Å Bump. We present a broadband spectrophotometric analysis of an unusual quasar, SDSS J160558.86+474300.1, at z = 0.9, found in a systematic search for reddened radio-loud narrow-line Seyfert 1 galaxies (NLS1s). J1605+4743 qualifies for the conventional definition of an NLS1 in its permitted emission line widths and Hβ/[O III] flux ratio. It also shows strong Fe II emissions. J1605+4743 has a steep radio spectrum. With a radio loudness of ~150 (70) before (after) reddening correction, it is among the most radio-loud NLS1s discovered. In addition, the blueshifted emission lines are also found to be weak, suggesting that it can be an exotic "wind-dominated" Seyfert similar to weak-line quasars, especially the ones with strong reddening. As an extreme hybrid central engine, its environment and host galaxy become rather intriguing. We discover in it a proximate 2175 Å absorber with a bump strength similar to the average value of 2175 Å absorbers in the Milky Way, which we suspect can be intrinsic to the quasar. In addition, the quasar seems to have enhanced instead of suppressed star formation at a rate of ≳94 M ⊙ yr-1. The combination of these unusual properties, i.e., the unique extinction, strong Fe II and [O II] lines, weak [O III], Mg II, and Balmer lines, and large radio loudness, might hold important clues to accretion physics, the formation/destruction of dust grains in the environment of active galactic nuclei, and possibly also the coevolution of supermassive black holes and their host galaxies in general.

Keywords: Quasar absorption line spectroscopy, Active galaxies, Emission line galaxies, Extinction, Radio active galactic nuclei
Electron Density Variations in the Interstellar Medium and the Average Frequency Profile of a Scintle from Pulsar Scintillation Spectra. We observed the scintillation pattern of nine bright pulsars at 324 MHz and three at 1.68 GHz and analyzed the wavenumber spectrum, which is related to electron density variations of the plasma turbulence of the interstellar medium (ISM). For all pulsars the frequency section of the autocorrelation function (ACF) of the dynamic spectra to at least 45% of the maximum corresponds to predictions of scattering theories with a range of power-law exponents of the wavenumber spectrum of 3.56 ≤ α ≤ 3.97 with errors ≤0.05 and a mean with standard deviation of 3.76 ± 0.13. The range includes α = 3.67 for the Kolmogorov spectrum. Similar results, although with larger errors, were found from the Fourier transform of the ACFs down to ~10-3 of the maximum. No clear case of a distinction between thin-screen and extended-medium scattering models was found. The average frequency profile of the scintles can be characterized for steep wavenumber spectra with α ≲ 4 by a cusp with a somewhat rounded peak. For flatter spectra, down to at least α ~ 3.56 the cusp with its peak becomes more pronounced and its decay steepens. We discuss our findings in the context of the scattering characteristics of the ISM.

Keywords: Interstellar scattering, Very long baseline interferometry, Radio pulsars, Interstellar scintillation
Unusual Abundances from Planetary System Material Polluting the White Dwarf G238-44. Ultraviolet and optical spectra of the hydrogen-dominated atmosphere white dwarf star G238-44 obtained with FUSE, Keck/HIRES, HST/COS, and HST/STIS reveal 10 elements heavier than helium: C, N, O, Mg, Al, Si, P, S, Ca, and Fe. G238-44 is only the third white dwarf with nitrogen detected in its atmosphere from polluting planetary system material. Keck/HIRES data taken on 11 nights over 24 yr show no evidence for variation in the equivalent width of measured absorption lines, suggesting stable and continuous accretion from a circumstellar reservoir. From measured abundances and limits on other elements, we find an anomalous abundance pattern and evidence for the presence of metallic iron. If the pollution is from a single parent body, then it would have no known counterpart within the solar system. If we allow for two distinct parent bodies, then we can reproduce the observed abundances with a mix of iron-rich Mercury-like material and an analog of an icy Kuiper Belt object with a respective mass ratio of 1.7:1. Such compositionally disparate objects would provide chemical evidence for both rocky and icy bodies in an exoplanetary system and would be indicative of a planetary system so strongly perturbed that G238-44 is able to capture both asteroid and Kuiper Belt-analog bodies near-simultaneously within its &lt;100 Myr cooling age.

Keywords: Stellar abundances, White dwarf stars, Exoplanet systems, Planetary dynamics
The Cavity of 3CR 196.1: Hα Emission Spatially Associated with an X-Ray Cavity. We present a multifrequency analysis of the radio galaxy 3CR 196.1 (z=0.198), associated with the brightest galaxy of the cool-core cluster CIZAJ0815.4-0303. This nearby radio galaxy shows a hybrid radio morphology and an X-ray cavity, all signatures of a turbulent past activity, potentially due to merger events and active galactic nuclei (AGN) outbursts. We present results of the comparison between Chandra and Very Large Telescope Multi-Unit Spectroscopic Explorer data for the inner region of the galaxy cluster, on a scale of tens of kpc. We discovered Hα + [N II]λ6584 emission spatially associated with the X-ray cavity (at ~10 kpc from the galaxy nucleus) instead of with its rim. This result differs from previous discoveries of ionized gas surrounding X-ray cavities in other radio galaxies harbored in galaxy clusters and could represent the first reported case of ionized gas filling an X-ray cavity, either due to different AGN outbursts or to the cooling of warm (104 &lt; T ≤ 107 K) AGN outflows. We also found that the Hα, [N II]λ λ6548, 6584, and [S II]λ λ6718, 6733 emission lines show an additional redward component, at ~1000 km s-1 from rest frame, with no detection in Hβ or [O III]λ λ4960, 5008. We believe the most likely explanation for this redward component is the presence of a background gas cloud as there appears to be a discrete difference of velocities between this component and the rest frame.

Keywords: Radio active galactic nuclei, Galaxy clusters, Active galactic nuclei, Cool cores
Dark Matter-admixed Rotating White Dwarfs as Peculiar Compact Objects. Discoveries of anomalous compact objects challenge our understanding of the standard theory of stellar structures and evolution, so they serve as an excellent laboratory for searching for new physics. Earlier studies on spherically symmetric dark matter (DM)-admixed compact stars could explain a handful of anomalies. In this paper, we investigate the observational signatures of DM-admixed rotating white dwarfs, and make connections to observed peculiar compact objects. We compute the equilibrium structures of DM-admixed rotating white dwarfs using a self-consistent, two-fluid method, with the DM component being a nonrotating degenerate Fermi gas. We find that admixing DM to rotating white dwarfs could: (1) account for some peculiar white dwarfs that do not follow their usual mass-radius relation; (2) allow stable rapid-rotating white dwarfs that are free from thermonuclear runaway to exist, which could explain some soft gamma-ray repeaters/anomalous X-ray pulsars; and (3) produce universal I (moment of inertia)-Love (tidal Love number)-Q (quadrupole moment) relations that span bands above those without DM admixture, thus providing an indirect way of searching for DM in white dwarfs through gravitational-wave detection. To conclude, DM-admixed rotating white dwarfs can account for some peculiar compact objects. Our results suggest a systematic approach to accounting for the unusual compact objects that upcoming surveys could discover.

Keywords: White dwarf stars, Stellar rotation, Dark matter, Gravitational waves
The Impact of Initial-Final Mass Relations on Black Hole Microlensing. Uncertainty in the initial-final mass relation (IFMR) has long been a problem in understanding the final stages of massive star evolution. One of the major challenges of constraining the IFMR is the difficulty of measuring the mass of nonluminous remnant objects (i.e., neutron stars and black holes). Gravitational-wave detectors have opened the possibility of finding large numbers of compact objects in other galaxies, but all in merging binary systems. Gravitational lensing experiments using astrometry and photometry are capable of finding compact objects, both isolated and in binaries, in the Milky Way. In this work we improve the Population Synthesis for Compact object Lensing Events (PopSyCLE) microlensing simulation code in order to explore the possibility of constraining the IFMR using the Milky Way microlensing population. We predict that the Roman Space Telescope's microlensing survey will likely be able to distinguish different IFMRs based on the differences at the long end of the Einstein crossing time distribution and the small end of the microlensing parallax distribution, assuming the small (π  E  ≲ 0.02) microlensing parallaxes characteristic of black hole lenses are able to be measured accurately. We emphasize that future microlensing surveys need to be capable of characterizing events with small microlensing parallaxes in order to place the most meaningful constraints on the IFMR.

Keywords: Gravitational microlensing, Stellar mass black holes, Astrophysical black holes, Stellar evolution
Detailed Calculations of the Efficiency of Planetesimal Accretion in the Core-accretion Model. II. The Effect of Saturn. As part of our ongoing initiative to accurately calculate the accretion rate of planetesimals in the core-accretion model, we demonstrated in a recent article that when the calculations include the gravitational force of the Sun (the original core-accretion model did not include solar gravity), results change considerably (ApJ, 899:45). In this paper, we have advanced our previous study by including the effect of Saturn. To maintain focus on the effect of this planet, and in order to be consistent with previous studies, we did not include the effect of the nebular gas. Results demonstrate that, as expected, Saturn's perturbation decreases the rate of accretion by scattering many planetesimals out of Jupiter's accretion zone. It also increases the velocities with which planetesimals encounter the envelope, which in agreement with our previous findings enhances their breakup due to the ram pressure. Results also show that, because the effect of Saturn in scattering of planetesimals increases with its mass, this planet might not have played a significant role in the accretion of planetesimals by proto-Jupiter during the early stage of its growth. Finally, the late accretion of planetesimals, as obtained in our previous study, appears in our new results as well, implying that, combined with the rapid infall of the gas, it can result in the mixing of material in the outer regions of the envelope, which may explain the enhancement of the envelope's high-Z material.

Keywords: Jupiter, Solar system gas giant planets, Planet formation, Planetesimals
The Small Separation A-star Companion Population: First Results with CHARA/MIRC-X. We present preliminary results from our long-baseline interferometry (LBI) survey to constrain the multiplicity properties of intermediate-mass A-type stars within 80 pc. Previous multiplicity studies of nearby stars exhibit orbital separation distributions well fitted with a lognormal with peaks &gt;15 au, increasing with primary mass. The A-star multiplicity survey of De Rosa et al., sensitive beyond 30 au but incomplete below 100 au, found a lognormal peak around 390 au. Radial velocity surveys of slowly rotating, chemically peculiar Am stars identified a significant number of very close companions with periods ≤5 days, ~0.1 au, a result similar to surveys of O- and B-type primaries. With the improved performance of LBI techniques, we can probe these close separations for normal A-type stars where other surveys are incomplete. Our initial sample consists of 27 A-type primaries with estimated masses between 1.44 and 2.49 M ⊙ and ages 10-790 Myr, which we observed with the MIRC-X instrument at the CHARA Array. We use the open-source software CANDID to detect five companions, three of which are new, and derive a companion frequency of ${0.19}_{-0.06}^{+0.11}$ over mass ratios of 0.25-1.0 and projected separations of 0.288-5.481 au. We find a probability of 10-6 that our results are consistent with extrapolations based on previous models of the A-star companion population over the mass ratios and separations sampled. Our results show the need to explore these very close separations to inform our understanding of stellar formation and evolution processes.

Keywords: Multiple stars, Binary stars, Close binary stars, Intermediate-type stars, Long baseline interferometry, Stellar types, Star formation, Chemically peculiar stars
Exploring Realistic Nanohertz Gravitational-wave Backgrounds. Hundreds of millions of supermassive black hole binaries are expected to contribute to the gravitational-wave signal in the nanohertz frequency band. Their signal is often approximated either as an isotropic Gaussian stochastic background with a power-law spectrum or as an individual source corresponding to the brightest binary. In reality, the signal is best described as a combination of a stochastic background and a few of the brightest binaries modeled individually. We present a method that uses this approach to efficiently create realistic pulsar timing array data sets using synthetic catalogs of binaries based on the Illustris cosmological hydrodynamic simulation. We explore three different properties of such realistic backgrounds that could help distinguish them from those formed in the early universe: (i) their characteristic strain spectrum, (ii) their statistical isotropy, and (iii) the variance of their spatial correlations. We also investigate how the presence of confusion noise from a stochastic background affects detection prospects of individual binaries. We calculate signal-to-noise ratios of the brightest binaries in different realizations for a simulated pulsar timing array based on the NANOGrav 12.5 yr data set extended to a time span of 15 yr. We find that ~6% of the realizations produce systems with signal-to-noise ratios larger than 5, suggesting that individual systems might soon be detected (the fraction increases to ~41% at 20 yr). These can be taken as a pessimistic prediction for the upcoming NANOGrav 15 yr data set, since it does not include the effect of potentially improved timing solutions and newly added pulsars.

Keywords: Supermassive black holes, Millisecond pulsars, Gravitational wave sources, Gravitational wave astronomy, Gravitational waves
LYRA. III. The Smallest Reionization Survivors. The dividing line between galaxies that are quenched by reionization ("relics") and galaxies that survive reionization (i.e., continue forming stars) is commonly discussed in terms of a halo mass threshold. We probe this threshold in a physically more complete and accurate way than has been possible to date, using five extremely high resolution (M target = 4 M ⊙) cosmological zoom-in simulations of dwarf galaxies within the halo mass range (1-4) × 109 M ⊙. The employed LYRA simulation model features resolved interstellar medium physics and individual, resolved supernova explosions. Interestingly, two out of five of the simulated dwarf galaxies lie close to the threshold mass but are neither full reionization relics nor full reionization survivors. These galaxies initially quench at the time of reionization but merely remain quiescent for ~500 Myr. At z ~ 5 they recommence star formation in a synchronous way and remain star-forming until the present day. The parallel timing indicates consistent sound-crossing and cooling times between the halos. While the star formation histories we find are diverse, we show that they are directly related to the ability of a given halo to retain and cool gas. Whereas the latter is most strongly dependent on the mass (or virial temperature) of the host halo at the time of reionization, it also depends on its growth history, the UV background (and its decrease at late times), and the amount of metals retained within the halo.

Keywords: Galaxy formation, Population III stars, Dwarf galaxies, Computational methods, Interstellar medium, Galaxy quenching, Reionization
Lost in Space: Companions' Fatal Dance around Massive Dying Stars. Discoveries of planet and stellar remnant hosting pulsars challenge our understanding, as the violent supernova explosion that forms the pulsar presumably destabilizes the system. Type II supernova explosions lead to the formation of eccentric bound systems, free-floating planets, neutron stars, pulsars, and white dwarfs. Analytical and numerical studies of high mass-loss rate systems based on perturbation theory so far have focused mainly on planet-star systems. In this paper, we extend our understanding of the fate of planet-star and binary systems by assuming a homologous envelope expansion model using a plausible ejection velocity (1000-10,000 km s-1), and envelope and neutron star masses. The investigation covers secondary masses of 1-10 M J for planetary companions and 1-20 M ⊙ for stellar companions. We conduct and analyze over 2.5 million simulations assuming different semimajor axes (2.23-100 au), eccentricities (0-0.8), and true anomalies (0-2π) for the companion. In a homologous expansion scenario, we confirm that the most probable outcome of the explosion is the destabilization of the system, while the retention of a bound system requires a highly eccentric primordial orbit. In general, a higher ejecta velocity results in a lower eccentricity orbit independent of secondary mass. The explanation of close-in pulsar planets requires exotic formation scenarios, rather than survival through the type II supernova explosion model. Postexplosion bound star systems gain a peculiar velocity (&lt;100 km s-1), even though the explosion model is symmetric. The applied numerical model allows us to derive velocity components for dissociating systems. The peculiar velocities of free-floating planets and stellar corpses are in the range of 10-6-275 km s-1.

Keywords: Exoplanet dynamics
The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament. We present 850 μm dust polarization observations of the massive DR21 filament from the B-fields In STar-forming Region Observations (BISTRO) survey, using the POL-2 polarimeter and the SCUBA-2 camera on the James Clerk Maxwell Telescope. We detect ordered magnetic fields perpendicular to the parsec-scale ridge of the DR21 main filament. In the subfilaments, the magnetic fields are mainly parallel to the filamentary structures and smoothly connect to the magnetic fields of the main filament. We compare the POL-2 and Planck dust polarization observations to study the magnetic field structures of the DR21 filament on 0.1-10 pc scales. The magnetic fields revealed in the Planck data are well-aligned with those of the POL-2 data, indicating a smooth variation of magnetic fields from large to small scales. The plane-of-sky magnetic field strengths derived from angular dispersion functions of dust polarization are 0.6-1.0 mG in the DR21 filament and ~0.1 mG in the surrounding ambient gas. The mass-to-flux ratios are found to be magnetically supercritical in the filament and slightly subcritical to nearly critical in the ambient gas. The alignment between column density structures and magnetic fields changes from random alignment in the low-density ambient gas probed by Planck to mostly perpendicular in the high-density main filament probed by James Clerk Maxwell Telescope. The magnetic field structures of the DR21 filament are in agreement with MHD simulations of a strongly magnetized medium, suggesting that magnetic fields play an important role in shaping the DR21 main filament and subfilaments.

Keywords: Interstellar filaments, Star forming regions, Interstellar magnetic fields, Submillimeter astronomy, Polarimetry
A Very Large Array Study of Newly Discovered Southern Latitude Nonthermal Filaments in the Galactic Center: Radio Continuum Total-intensity and Spectral Index Properties. The nonthermal filament (NTF) radio structures clustered within a few hundred parsecs of the Galactic center (GC) are apparently unique to this region of the Galaxy. Recent radio images of the GC using MeerKAT at 1 GHz have revealed a multitude of faint, previously unknown NTF bundles (NTFBs), some of which are comprised of as many as 10 or more individual filaments. In this work we present Very Large Array observations at the C- and X-bands (4-12 GHz) at arcsecond-scale resolutions of three of these newly discovered NTFBs, all located at southern Galactic latitudes. These observations allow us to compare their total-intensity properties with those of the larger NTF population. We find that these targets generally possess properties similar to what is observed in the larger NTF population. However, the larger NTF population generally has steeper spectral indices than what we observe for our chosen targets. The results presented here based on the total-intensity properties of these structures indicate that the NTFs are likely a result of synchrotron emission from relativistic electrons that have been generated either by a nearby compact source or by extended magnetic field structures in which the magnetic field line reconnection has accelerated the electrons. In either scenario, once the relativistic electrons are produced and injected locally into the field they diffuse along the magnetic field lines, producing the filaments.

Keywords: Galactic center, Galactic cosmic rays, Non-thermal radiation sources, Spectral index, Radio astronomy
Numerical Simulations of Oscillations in Solar Corona Excited by Vortex Shedding. We study transverse oscillations of plasma structures in the solar corona excited by vortex shedding solving the full set of the 3D ideal time-dependent magnetohydrodynamic equations. To present how the creation of vortices and excited oscillations depend on the initial flow speed and various values of the magnetic field, we performed a parametric study for two cases, an interaction of a steady flow with a rigid and spatially fixed cylindrical obstacle, and with a cylinder fixed at the boundaries. We show that generated vortices can excite oscillations, e.g., transverse (kink), in the solar corona, for example in coronal loops, filaments, flux ropes, or similar magnetic structures. It has been found that the oscillation period is close to the theoretically predicted value. Moreover, we study the dependence of the Strouhal number with respect to the magnetic field under the conditions of the solar atmosphere.

Keywords: Solar coronal waves