Sazuna/UAT_keywords huggingface dataset:
Quijote-PNG: The Information Content of the Halo Mass Function. We study signatures of primordial non-Gaussianity (PNG) in the redshift-space halo field on nonlinear scales using a combination of three summary statistics, namely, the halo mass function (HMF), power spectrum, and bispectrum. The choice of adding the HMF to our previous joint analysis of the power spectrum and bispectrum is driven by a preliminary field-level analysis, in which we train graph neural networks on halo catalogs to infer the PNG f NL parameter. The covariance matrix and the responses of our summaries to changes in model parameters are extracted from a suite of halo catalogs constructed from the QUIJOTE-PNG N-body simulations. We consider the three main types of PNG: local, equilateral, and orthogonal. Adding the HMF to our previous joint analysis of the power spectrum and bispectrum produces two main effects. First, it reduces the equilateral f NL predicted errors by roughly a factor of 2 while also producing notable, although smaller, improvements for orthogonal PNG. Second, it helps break the degeneracy between the local PNG amplitude, ${f}_{\mathrm{NL}}^{\mathrm{local}}$ , and assembly bias, b  ϕ , without relying on any external prior assumption. Our final forecasts for the PNG parameters are ${\rm{\Delta }}{f}_{\mathrm{NL}}^{\mathrm{local}}=40$ , ${\rm{\Delta }}{f}_{\mathrm{NL}}^{\mathrm{equil}}=200$ , ${\rm{\Delta }}{f}_{\mathrm{NL}}^{\mathrm{ortho}}=85$ , on a cubic volume of $1{\left(\mathrm{Gpc}/{\rm{h}}\right)}^{3}$ , with a halo number density of $\bar{n}\sim 5.1\,\times \,{10}^{-5}\,{h}^{3}\,{\mathrm{Mpc}}^{-3}$ , at z = 1, and considering scales up to ${k}_{\max }=0.5\,h\,{\mathrm{Mpc}}^{-1}$ .

Keywords: Non-Gaussianity, Fisher's Information, Large-scale structure of the universe
Centaurus A: Exploring the Nature of the Hard X-Ray/Soft Gamma-Ray Emission with INTEGRAL. The question of the origin of the hard X-ray/soft gamma-ray emission in Centaurus A (Cen A) persists despite decades of observations. Results from X-ray instruments suggest a jet origin since the implied electron temperature (kT  e ) would cause runaway pair production in the corona. In contrast, instruments sensitive to soft gamma rays report electron temperatures indicating that a coronal origin may be possible. In this context, we analyzed archival INTEGRAL/IBIS-ISGRI and SPI data and observations from a 2022 Cen A monitoring program. Our analysis did not find any spectral variability. Thus we combined all observations for long-term average spectra, which were fit with a NuSTAR observation to study the 3.5 keV-2.2 MeV spectrum. Spectral fits using a CompTT model found kT  e  ~ 550 keV, near runaway pair production. The spectrum was also well described by a log-parabola to model synchrotron self-Compton emission from the jet. Additionally, a spectral fit with the 12 yr catalog Fermi/LAT spectrum using a log-parabola can explain the data up to ~3 GeV. Above ~3 GeV, a power-law excess is present, which has been previously reported in LAT/H.E.S.S. analysis. However, including a coronal spectral component can also describe the data well. In this scenario, the hard X-rays/soft gamma rays are due the corona and the MeV to GeV emission is due to the jet.

Keywords: Active galactic nuclei, Gamma-rays
Probing the Solar Interior with Lensed Gravitational Waves from Known Pulsars. When gravitational waves (GWs) from a spinning neutron star arrive from behind the Sun, they are subjected to gravitational lensing that imprints a frequency-dependent modulation on the waveform. This modulation traces the projected solar density and gravitational potential along the path as the Sun passes in front of the neutron star. We calculate how accurately the solar density profile can be extracted from the lensed GWs using a Fisher analysis. For this purpose, we selected three promising candidates (the highly spinning pulsars J1022+1001, J1730-2304, and J1745-23) from the pulsar catalog of the Australia Telescope National Facility. The lensing signature can be measured with 3σ confidence when the signal-to-noise ratio (S/N) of the GW detection reaches 100 (f/300 Hz)-1 over a 1 yr observation period (where f is the GW frequency). The solar density profile can be plotted as a function of radius when the S/N improves to ≳104.

Keywords: Gravitational wave astronomy, The Sun, Gravitational lensing, Pulsars
Peculiar Spectral Property of Coherent Radio Emission from a Hot Magnetic Star: The Case of an Extreme Oblique Rotator. We report ultra-wideband (0.4–4.0 GHz) observation of coherent radio emission via electron cyclotron maser emission (ECME) produced by the hot magnetic star HD 142990. With nearly perpendicular rotation and magnetic dipole axes, it represents an extreme case of oblique rotators. The large obliquity is predicted to cause a complex distribution of stellar wind plasma in the magnetosphere. It has been proposed that such a distribution will give rise to a nontrivial frequency dependence of ECME. Indeed we discovered strong frequency dependence of different pulse properties, such as the appearance of secondary pulses, different cutoff frequencies for pulses observed at different rotational phases, etc. But the unique feature that we observed is that while at sub-gigahertz frequencies, the star appears to produce ECME in the extraordinary mode, at gigahertz frequencies, the mode indicated by the pulse property is the ordinary mode. By considering the physical condition needed by such a scenario, we conclude that the required transition of the magnetoionic mode with frequency is unlikely to occur, and the most promising scenario is refraction caused by the complex plasma distribution surrounding the star. This suggests that the conventional way to deduce the magnetoionic mode based on ECME observed at a given frequency is not a reliable method for stars with large misalignment between their rotation and magnetic axes. We also find that ECME exhibits an upper cutoff at ≲3.3 GHz, which is much smaller than the frequency corresponding to the maximum stellar magnetic field strength.

Keywords: Observational astronomy, Early-type stars, Magnetic stars, Periodic variable stars, Main sequence stars, OB stars, Non-thermal radiation sources, Astrophysical masers, Magnetic variable stars, Radio continuum emission
NGC 6302: The Tempestuous Life of a Butterfly. NGC 6302 (The Butterfly Nebula) is an extremely energetic and rapidly expanding bipolar planetary nebula (PN). If the central source is a single star, then its apparent location in an H-R diagram places it among the most massive, hottest, and presumably rapidly evolving of all central stars of PNe. Our proper motion study of NGC 6302, based on Hubble Space Telescope WFC3 images spanning 11 yr, has uncovered at least four different pairs of uniformly expanding internal lobes ejected at various times and orientations over the past two millennia at speeds ranging from 10-600 km s-1. In addition, we find a pair of collimated off-axis flows in constant motion at ~770 ± 100 km s-1 within which bright [Fe II] feathers are conspicuous. Combining our results with those previously published, we find that the ensemble of flows has an ionized mass &gt;0.1 M ⊙ and its kinetic energy, between 1046 and 1048 erg, lies at the upper end of gravity-powered PNe ejection processes such as stellar mergers or mass accretion. We assemble our results into a plausible historical timeline of ejections from the nucleus and suggest that the ejections are powered by gravitational infall.

Keywords: Ejecta, Stellar wind bubbles, Bipolar nebulae, Planetary nebulae, Shocks
Magnetic Structures and Turbulence in SN 1006 Revealed with Imaging X-Ray Polarimetry. Young supernova remnants strongly modify the surrounding magnetic fields, which in turn play an essential role in accelerating cosmic rays (CRs). The X-ray polarization measurements probe magnetic field morphology and turbulence at the immediate acceleration site. We report the X-ray polarization distribution in the northeastern shell of SN 1006 from a 1 Ms observation with the Imaging X-ray Polarimetry Explorer. We found an average polarization degree of 22.4% ± 3.5% and an average polarization angle of -45.°4 ± 4.°5 (measured on the plane of the sky from north to east). The X-ray polarization angle distribution reveals that the magnetic fields immediately behind the shock in the northeastern shell of SN 1006 are nearly parallel to the shock normal or radially distributed, similar to that in the radio observations, and consistent with the quasi-parallel CR acceleration scenario. The X-ray emission is marginally more polarized than that in the radio band. The X-ray polarization degree of SN 1006 is much larger than that in Cas A and Tycho, together with the relatively tenuous and smooth ambient medium of the remnant, favoring that CR-induced instabilities set the magnetic turbulence in SN 1006, and CR acceleration is environment-dependent.

Keywords: X-ray astronomy, Supernova remnants, Shocks, Polarimetry, Cosmic rays
Needle in a Haystack: Finding Supermassive Black Hole-related Flares in the Zwicky Transient Facility Public Survey. Transient accretion events onto supermassive black holes (SMBHs), such as tidal disruption events (TDEs), Bowen Fluorescence Flares (BFFs), and active galactic nuclei (AGNs), which are accompanied by sudden increases of activity, offer a new window onto the SMBH population, accretion physics, and stellar dynamics in galaxy centers. However, such transients are rare and finding them in wide-field transient surveys is challenging. Here we present the results of a systematic real-time search for SMBH-related transients in Zwicky Transient Facility (ZTF) public alerts, using various search queries. We examined 345 rising events coincident with a galaxy nucleus, with no history of previous activity, of which 223 were spectroscopically classified. Of those, five (2.2%) were TDEs, one (0.5%) was a BFF, and two (0.9%) were AGN flares. Limiting the search to blue events, the fraction of TDEs nearly doubles to 4.1%, and no TDEs are missed. Limiting the search further to candidate post-starburst galaxies increases the relative number of TDEs to 16.7%, but the absolute numbers in such a search are small. The main contamination source is supernovae (95.1% of classified events), of which the majority (82.2% of supernovae) are of Type Ia. In a comparison set of 39 events with limited photometric history, the AGN contamination increases to ~30%. Host galaxy offset is not a significant discriminant of TDEs in current ZTF data, but might be useful in higher-resolution data. Our results can be used to quantify the efficiency of various SMBH-related transient search strategies in optical surveys such as ZTF and the Legacy Survey of Space and Time.

Keywords: Supermassive black holes, Tidal disruption, Active galactic nuclei, Astronomical methods, Supernovae
The Impulsive Acceleration of a Solar Filament Eruption Associated with a B-class Flare. The eruption of magnetic flux ropes (MFRs), often taking filaments together, leads to coronal mass ejections (CMEs). Theoretical studies propose that both the resistive magnetic reconnection and the ideal instability of an MFR system can release magnetic-free energy and accelerate CMEs (i.e., MFRs or filaments) during eruptions. Observations find that the full kinematic evolution of CMEs usually undergoes three phases: the initiation phase, impulsive acceleration phase, and propagation phase. The impulsive acceleration phase often starts and ceases simultaneously with the flare onset time and peak time, respectively. This synchronization can be explained by the positive feedback relationship between the acceleration of CMEs and flare magnetic reconnection, and suggests that the reconnection has the dominant contribution to the acceleration of CMEs. It is rare to see strong evidence that supports the dominant contribution of ideal instability to the acceleration. In this paper, we report an intriguing filament eruption that occurred on 2011 May 11. Its complete acceleration is well recorded by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. The kinematic analysis shows that the impulsive acceleration phase starts and ceases obviously earlier than the flare onset time and peak time, respectively, which means a complete asynchronization between the impulsive acceleration phase and flare rise phase, and strongly supports that the ideal instability plays a dominant role in this impulsive acceleration. Furthermore, the accompanied flare is a B-class one, also implying that the contribution of reconnection is negligible in the energy release process.

Keywords: Solar activity, Solar flares, Solar filament eruptions
Low-mass Quiescent Galaxies Are Small in Isolated Environments: Environmental Dependence of the Mass-Size Relation of Low-mass Quiescent Galaxies. We study the mass-size relation of quiescent galaxies across various environments, with a particular focus on its environmental dependence at the low-mass part of $\mathrm{log}({M}_{\mathrm{star}}/{M}_{\odot })\lesssim 10.0$ . Our sample consists of 13,667 quiescent galaxies with $\mathrm{log}({M}_{\mathrm{star}}/{M}_{\odot })\geqslant 9.4$ and 0.01 &lt; z &lt; 0.04 from the Sloan Digital Sky Survey. We discover that the mass-size relation of low-mass quiescent galaxies (LQGs) with $\mathrm{log}({M}_{\mathrm{star}}/{M}_{\odot })\lesssim 10.0$ depends on their environment, with LQGs in the highest-density environments exhibiting an average size ~70% larger than those in isolated environments. Moreover, the slope of the mass-size relation for LQGs in high-density environments is significantly shallower than that of their counterparts in isolated environments. This is in contrast with high-mass quiescent galaxies with $\mathrm{log}({M}_{\mathrm{star}}/{M}_{\odot })\gtrsim 10.5$ that show a nearly identical mass-size relation across all environments. Combined with additional discoveries that the mass-size relation slopes of LQGs and star-forming galaxies are similar to each other in high-density environments, and that LQGs in higher-density environments exhibit more disk-like structures, our results support the idea that LQGs in high-density environments have evolved from star-forming galaxies through environmental effects, which are capable of causing their quenching and transformation into quiescent galaxies. With the aid of an analysis of merger rates for simulated galaxies from a cosmological galaxy formation simulation, we suggest that the steep slope and low normalization of the mass-size relation of LQGs in the lowest-density environments may originate from recent gas-rich mergers, which occur over 10-30 times more frequently in the progenitors of LQGs in the lowest-density environments than in their counterparts in high-density environments at low redshifts.

Keywords: Galaxy formation, Quenched galaxies, Galaxy environments, Galaxy structure, Galaxy evolution, Galaxy mergers, Early-type galaxies
Turbulent Structure in Supernova Remnants G46.8-0.3 and G39.2-0.3 from THOR Polarimetry. We present the continued analysis of polarization and Faraday rotation for the supernova remnants (SNRs) G46.8-0.3 and G39.2-0.3 in L-band (1-2 GHz) radio continuum in The H I/OH/Recombination line (THOR) survey. In this work, we present our investigation of Faraday depth fluctuations from angular scales comparable to the size of the SNRs down to scales less than our 16″ beam (≲0.7 pc) from Faraday dispersion (σ  ϕ ). From THOR, we find median σ  ϕ  of 15.9 ± 3.2 rad m-2 for G46.8-0.3 and 17.6 ± 1.6 rad m-2 for G39.2-0.3. When comparing to polarization at 6 cm, we find evidence for σ  ϕ  ≳ 30 rad m-2 in localized regions where we detect no polarization in THOR. We combine Faraday depth dispersion with the rotation measure (RM) structure function (SF) and find evidence for a break in the SF on scales less than the THOR beam. We estimate the RM SF of the foreground interstellar medium using the SF of extragalactic radio sources and pulsars to find that the RM fluctuations we measure originate within the SNRs for all but the largest angular scales.

Keywords: Supernova remnants, Interstellar magnetic fields, Interstellar medium, Radio continuum emission, Polarimetry
Investigating the Globally Collapsing Hub-Filament Cloud G326.611+0.811. We present a dynamics study toward the G326.611+0.811 (G326) hub-filament system (HFS) cloud using new APEX observations of both 13CO and C18O (J = 2-1). The G326 HFS cloud constitutes a central hub and at least four hub-composing filaments that are divided into a major branch of filaments (F1 and F2) and a side branch (F3-F5). The cloud holds ongoing high-mass star formation as characterized by three massive dense clumps (i.e., 370-1100 M ⊙ and 0.14-0.16 g cm-2 for C1-C3) with high clump-averaged mass infalling rates (&gt;10-3 M ⊙ yr-1) within the major filament branch, and the associated point sources bright at 70 μm, typical of young protostars. Along the five filaments, velocity gradients are found in both 13CO and C18O (J = 2-1) emission, suggesting that filament-aligned gravitational collapse toward the central hub (i.e., C2) is responsible for the high-mass star formation therein. Moreover, a periodic velocity oscillation along the major filament branch is revealed in both 13CO and C18O (J = 2-1) emission with a characteristic wavelength of ~3.5 pc and an amplitude of ~0.31-0.38 km s-1. We suggest that this pattern of velocity oscillation in G326 could arise from clump-forming gas motion induced by gravitational instabilities. The prevalent velocity gradients, fragmentation of the major branch of filaments, and the ongoing collapse of the three massive dense clumps are indicative that G326 is an HFS undergoing global collapse.

Keywords: Star forming regions, Interstellar filaments, Infrared dark clouds
Sesquinary Catastrophe for Close-in Moons with Dynamically Excited Orbits. We identify a new mechanism that can lead to the destruction of small, close-in planetary satellites. If a small moon close to the planet has a sizable eccentricity and inclination, its ejecta that escape to the planetocentric orbit would often reimpact with much higher velocity due to the satellite's and fragment's orbits precessing out of alignment. If the impacts of returning ejecta result in net erosion, a runaway process can occur that may end in disruption of the satellite, and we term this process "sesquinary catastrophe." We expect the moon to reaccrete, but on an orbit with significantly lower eccentricity and inclination. We find that the large majority of small close-in moons in the solar system have orbits that are immune to sesquinary catastrophe. The exceptions include a number of resonant moonlets of Saturn for which resonances may affect the velocities of reimpact of their own debris. Additionally, we find that Neptune's moon Naiad (and to a lesser degree, Jupiter's Thebe) must have substantial internal strength, in line with prior estimates based on Roche limit stability. We also find that sesquinary instability puts important constraints on the plausible past orbits of Phobos and Deimos or their progenitors.

Keywords: Collisional processes, Natural satellites (Solar system), Natural satellite evolution, Natural satellite dynamics
Illuminating the Dark Side of Cosmic Star Formation. II. A Second Date with RS-NIRdark Galaxies in COSMOS. About 12 billion years ago, the Universe was first experiencing light again after the dark ages, and galaxies filled the environment with stars, metals, and dust. How efficient was this process? How fast did these primordial galaxies form stars and dust? We can answer these questions by tracing the star formation rate density (SFRD) back to its widely unknown high-redshift tail, traditionally observed in the near-infrared (NIR), optical, and UV bands. Thus, objects with a large amount of dust were missing. We aim to fill this knowledge gap by studying radio-selected NIR-dark (RS-NIRdark) sources, i.e., sources not having a counterpart at UV-to-NIR wavelengths. We widen the sample of Talia et al. from 197 to 272 objects in the Cosmic Evolution Survey (COSMOS) field, including also photometrically contaminated sources, which were previously excluded. Another important step forward consists in the visual inspection of each source in the bands from u* to MIPS 24 μm. According to their "environment" in the different bands, we are able to highlight different cases of study and calibrate an appropriate photometric procedure for the objects affected by confusion issues. We estimate that the contribution of RS-NIRdark sources to the cosmic SFRD at 3 &lt; z &lt; 5 is ~10%-25% of that based on UV-selected galaxies.

Keywords: Galaxy formation, Extragalactic radio sources, Star formation, Galaxy evolution, High-redshift galaxies
The SN 2023ixf Progenitor in M101. I. Infrared Variability. Observational evidence points to a red supergiant (RSG) progenitor for SN 2023ixf. The progenitor candidate has been detected in archival images at wavelengths (≥0.6 μm) where RSGs typically emit profusely. This object is distinctly variable in the infrared (IR). We characterize the variability using pre-explosion mid-IR (3.6 and 4.5 μm) Spitzer and ground-based near-IR (JHK  s ) archival data jointly covering 19 yr. The IR light curves exhibit significant variability with rms amplitudes in the range 0.2-0.4 mag, increasing with decreasing wavelength. From a robust period analysis of the more densely sampled Spitzer data, we measure a period of 1091 ± 71 days. We demonstrate using Gaussian process modeling that this periodicity is also present in the near-IR light curves, thus indicating a common physical origin, which is likely pulsational instability. We use a period-luminosity relation for RSGs to derive a value of M  K  = -11.58 ± 0.31 mag. Assuming a late M spectral type, this corresponds to $\mathrm{log}(L/{L}_{\odot })=5.27\pm 0.12$ at T eff = 3200 K and to $\mathrm{log}(L/{L}_{\odot })=5.37\pm 0.12$ at T eff = 3500 K. This gives an independent estimate of the progenitor's luminosity, unaffected by uncertainties in extinction and distance. Assuming the progenitor candidate underwent enhanced dust-driven mass loss during the time of these archival observations, and using an empirical period-luminosity-based mass-loss prescription, we obtain a mass-loss rate of around (2-4) × 10-4 M ☉ yr-1. Comparing the above luminosity with stellar evolution models, we infer an initial mass for the progenitor candidate of 20 ± 4 M ☉, making this one of the most massive progenitors for a Type II SN detected to date.

Keywords: Massive stars, Circumstellar dust, Supernovae, Variable stars
Beyond Spectroscopy. II. Stellar Parameters for over 20 Million Stars in the Northern Sky from SAGES DR1 and Gaia DR3. We present precise photometric estimates of stellar parameters, including effective temperature, metallicity, luminosity classification, distance, and stellar age, for nearly 26 million stars using the methodology developed in the first paper of this series, based on the stellar colors from the Stellar Abundances and Galactic Evolution Survey (SAGES) Data Release 1 and Gaia Early Data Release 3. The optimal design of stellar-parameter sensitive uv filters by SAGES has enabled us to determine photometric-metallicity estimates down to -3.5, similar to our previous results with the SkyMapper Southern Survey (SMSS), yielding a large sample of over five million metal-poor ([Fe/H] ≤ -1.0) stars and nearly one million very metal-poor ([Fe/H] ≤ -2.0) stars. The typical precision is around 0.1 dex for both dwarf and giant stars with [Fe/H] &gt; -1.0, and 0.15-0.25/0.3-0.4 dex for dwarf/giant stars with [Fe/H] &lt; -1.0. Using the precise parallax measurements and stellar colors from Gaia, effective temperature, luminosity classification, distance, and stellar age are further derived for our sample stars. This huge data set in the Northern sky from SAGES, together with similar data in the Southern sky from SMSS, will greatly advance our understanding of the Milky Way, in particular its formation and evolution.

Keywords: Fundamental parameters of stars, Galaxy abundances, Milky Way Galaxy, Ultraviolet surveys