Sazuna/UAT_keywords huggingface dataset:
The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VI. The Core-scale CO Depletion. Studying the physical and chemical properties of cold and dense molecular clouds is crucial for the understanding of how stars form. Under the typical conditions of infrared dark clouds, CO is removed from the gas phase and trapped onto the surface of dust grains by the so-called depletion process. This suggests that the CO-depletion factor (f D ) can be a useful chemical indicator for identifying cold and dense regions (i.e., prestellar cores). We have used the 1.3 mm continuum and C18O (2-1) data observed at the resolution of ~5000 au in the ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES) to construct averaged maps of f D in 12 clumps to characterize the earliest stages of the high-mass star formation process. The average f D determined for 277 of the 294 ASHES cores follows an unexpected increase from the prestellar to the protostellar stage. If we exclude the temperature effect due to the slight variations in the NH3 kinetic temperature among different cores, we explain this result as a dependence primarily on the average gas density, which increases in cores where protostellar conditions prevail. This shows that f D determined in high-mass star-forming regions at the core scale is insufficient to distinguish among prestellar and protostellar conditions for the individual cores and should be complemented by information provided by additional tracers. However, we confirm that the clump-averaged f D values correlate with the luminosity-to-mass ratio of each source, which is known to trace the evolution of the star formation process.

Keywords: Interstellar line emission, Infrared dark clouds, Massive stars, Star forming regions, Astrochemistry, Star formation, Interstellar medium
Continued PSP/WISPR Observations of a Phaethon-related Dust Trail. We present an update to the first white-light detections of a dust trail observed closely following the orbit of asteroid (3200) Phaethon, as seen by the Wide-field Imager for the Parker Solar Probe instrument on the NASA Parker Solar Probe mission. Here, we provide a summary and analysis of observations of the dust trail over nine separate mission encounters between 2018 October and 2021 August that saw the spacecraft approach to within 0.0277 au of the orbit of Phaethon. We find the photometric and estimated dust mass properties to be in line with those in the initial publication, with a visual (V) magnitude of V ~ 16.1 ± 0.3 pixel-1, corresponding to a surface brightness of 26.1 mag arcsec-2, and an estimated mass of dust within the range 1010-1012 kg depending on the assumed dust properties. However, the key finding of this survey is the discovery that the dust trail does not perfectly follow the orbit of Phaethon, with a clear separation noted between them that increases as a function of true anomaly, though the trail may differ from Phaethon's orbit by as little as 1° in periapsis.

Keywords: Meteoroid dust clouds, Near-Earth objects, Asteroids, Small Solar System bodies
A Hidden Population of Massive Black Holes in Simulated Dwarf Galaxies. We explore the characteristics of actively accreting massive black holes (MBHs) within dwarf galaxies in the ROMULUS25 cosmological hydrodynamic simulation. We examine the MBH occupation fraction, X-ray active fractions, and active galactic nucleus (AGN) scaling relations within dwarf galaxies of stellar mass 108 M ⊙ &lt; M star &lt; 1010 M ⊙ out to redshift z = 2. In the local universe, the MBH occupation fraction is consistent with observed constraints, dropping below unity at M star &lt; 3 × 1010 M ⊙, M 200 &lt; 3 × 1011 M ⊙. Local dwarf AGN in ROMULUS25 follow observed scaling relations between AGN X-ray luminosity, stellar mass, and star formation rate, though they exhibit slightly higher active fractions and number densities than comparable X-ray observations. Since z = 2, the MBH occupation fraction has decreased, the population of dwarf AGN has become overall less luminous, and as a result the overall number density of dwarf AGN has diminished. We predict the existence of a large population of MBHs in the local universe with low X-ray luminosities and high contamination from X-ray binaries and the hot interstellar medium that are undetectable by current X-ray surveys. These hidden MBHs make up 76% of all MBHs in local dwarf galaxies and include many MBHs that are undermassive relative to their host galaxy's stellar mass. Their detection relies on not only greater instrument sensitivity but also better modeling of X-ray contaminants or multiwavelength surveys. Our results indicate that dwarf AGN were substantially more active in the past, despite having low luminosity today, and that future deep X-ray surveys may uncover many hidden MBHs in dwarf galaxies out to at least z = 2.

Keywords: Hydrodynamical simulations, Dwarf galaxies, Active galaxies, Supermassive black holes
Manifestation of Gravitational Settling in Coronal Mass Ejections Measured in the Heliosphere. Elemental composition in the solar wind reflects the fractionation processes at the Sun. In coronal mass ejections (CMEs) measured in the heliosphere, the elemental composition can vary between plasma of high and low ionization states as indicated by the average Fe charge state, &lt;QFe&gt;. It is found that CMEs with higher ionized plasma, &lt;QFe&gt; greater than 12, are significantly more enriched in low first ionization potential (FIP) elements compared to their less ionized, &lt;QFe&gt; less than 12, counterparts. In addition, the CME elemental composition has been shown to vary along the solar cycle. However, the processes driving changes in elemental composition in the plasma are not well understood. To gain insight into this variation, this work investigates the effects of gravitational settling in the ejecta to examine how that process can modify signatures of the FIP effect found in CMEs. We examine the absolute abundances of C, N, O, Ne, Mg, Si, S, and Fe in CMEs between 1998 and 2011. Results show that the ejecta exhibits some gravitational settling effects in approximately 33% of all CME periods in plasma where the Fe abundance of the ejecta compared to the solar wind (Fe/HCME:Fe/HSW) is depleted compared to the C abundance (C/HCME:C/HSW). We also find gravitational settling is most prominent in CMEs during solar minimum; however, it occurs throughout the solar cycle. This study indicates that gravitational settling, along with the FIP effect, can become important in governing the compositional makeup of CME source regions.

Keywords: Solar cycle, Solar coronal transients, Solar coronal mass ejections, Chemical abundances
The R-Process Alliance: Abundance Universality among Some Elements at and between the First and Second R-Process Peaks. We present new observational benchmarks of rapid neutron-capture process (r-process) nucleosynthesis for elements at and between the first (A ~ 80) and second (A ~ 130) peaks. Our analysis is based on archival ultraviolet and optical spectroscopy of eight metal-poor stars with Se (Z = 34) or Te (Z = 52) detections, whose r-process enhancement varies by more than a factor of 30 (-0.22 ≤ [Eu/Fe] ≤ +1.32). We calculate ratios among the abundances of Se, Sr through Mo (38 ≤ Z ≤ 42), and Te. These benchmarks may offer a new empirical alternative to the predicted solar system r-process residual pattern. The Te abundances in these stars correlate more closely with the lighter r-process elements than the heavier ones, contradicting and superseding previous findings. The small star-to-star dispersion among the abundances of Se, Sr, Y, Zr, Nb, Mo, and Te (≤0.13 dex, or 26%) matches that observed among the abundances of the lanthanides and third r-process-peak elements. The concept of r-process universality that is recognized among the lanthanide and third-peak elements in r-process-enhanced stars may also apply to Se, Sr, Y, Zr, Nb, Mo, and Te, provided the overall abundances of the lighter r-process elements are scaled independently of the heavier ones. The abundance behavior of the elements Ru through Sn (44 ≤ Z ≤ 50) requires further study. Our results suggest that at least one relatively common source in the early Universe produced a consistent abundance pattern among some elements spanning the first and second r-process peaks. * Based on archival observations made with the NASA/ESA Hubble Space Telescope (program GO-7348, program GO-8342, program GO-9455, program GO-14161, and program GO-14672) and observations collected from the Keck Observatory Archive (program U25H).

Keywords: Ultraviolet astronomy, Stellar abundances, R-process, Nucleosynthesis
Call and Response: A Time-resolved Study of Chromospheric Evaporation in a Large Solar Flare. We studied an X1.6 solar flare produced by NOAA Active Region 12602 on 2014 October 22. The entirety of this event was covered by RHESSI, IRIS, and Hinode/EIS, allowing analysis of the chromospheric response to a nonthermal electron driver. We derived the energy contained in nonthermal electrons via RHESSI spectral fitting and linked the time-dependent parameters of this call to the response in Doppler velocity, density, and nonthermal width across a broad temperature range. The total energy injected was 4.8 × 1030 erg and lasted 352 s. This energy drove explosive chromospheric evaporation, with a delineation in both Doppler and nonthermal velocities at the flow reversal temperature, between 1.35 and 1.82 MK. The time of peak electron injection (14:06 UT) corresponded to the time of highest velocities. At this time, we found 200 km s-1 blueshifts in the core of Fe XXIV, which is typically assumed to be at rest. Shortly before this time, the nonthermal electron population had the shallowest spectral index (≈6), corresponding to the peak nonthermal velocity in Si IV and Fe XXI. Nonthermal velocities in Fe XIV, formed near the flow reversal temperature, were low and not correlated with density or Doppler velocity. Nonthermal velocities in ions with similar temperatures were observed to increase and correlate with Doppler velocities, implying unresolved flows surrounding the flow reversal point. This study provides a comprehensive, time-resolved set of chromospheric diagnostics for a large X-class flare, along with a time-resolved energy injection profile, ideal for further modeling studies.

Keywords: Solar active region velocity fields, Solar flares, Solar ultraviolet emission, Solar extreme ultraviolet emission, Solar transition region, Solar flare spectra, Solar x-ray flares, Solar activity, Solar chromosphere, Active solar chromosphere
Wide-band Timing of GMRT-discovered Millisecond Pulsars. Modeling of frequency-dependent effects, contributed by the turbulence in the free electron density of interstellar plasma, is required to enable the detection of the expected imprints from the stochastic gravitational-wave (GW) background in pulsar timing data. In this work, we present an investigation of temporal variations of interstellar medium for a set of millisecond pulsars (MSPs) with the upgraded Giant Metrewave Radio Telescope (GMRT) aided by large fractional bandwidth at lower observing frequencies. Contrary to the conventional narrowband analysis using a frequency-invariant template profile, we applied PulsePortraiture-based wide-band timing analysis while correcting for the evolution of the pulsar profile with frequency. Implementation of the PulsePortraiture-based wide-band timing method for the GMRT-discovered MSPs to probe the dispersion measure (DM) variations resulted in a DM precision of 10-4 pc cm-3. In general, we achieve similar DM and timing precision from wide-band timing compared to the narrowband timing with matching temporal variations of DMs. This wide-band timing study of newly discovered MSPs over a wide frequency range highlights the effectiveness of profile modeling at low frequencies and probes the potential of using them in a pulsar timing array.

Keywords: Millisecond pulsars, Astronomical techniques, Pulsar timing method, Pulsars
Do Cellular Automaton Avalanche Models Simulate the Quasi-periodic Pulsations of Solar Flares?. Quasi-periodic pulsations (QPPs) with various periods that originate in the underlying magnetohydrodynamic processes of flaring structures are detected repeatedly in solar flare emissions. We apply a 2D cellular automaton (CA) avalanche model to simulate QPPs as a result of a repetitive load/unload mechanism. We show that the frequent occurrence of magnetic reconnections in a flaring loop could induce quasi-periodic patterns in the detected emissions. We find that among 21,070 simulated flares, 813 events last over 50 s, scaled with the temporal resolution of the Yohkoh Hard X-ray Telescope, and about 70% of these rather long-lasting events exhibit QPPs. We also illustrate that the applied CA model provides a wide range of periodicities for QPPs. Furthermore, we observe the presence of multiple periods in nearly 50% of the cases by applying the Lomb-Scargle periodogram. A lognormal distribution is fitted to the unimodal distribution of the periods as a manifestation of an underlying multiplicative mechanism that typifies the effect of the system's independently varying parameters. The global maximum of the periods' lognormal distribution is located at 29.29 ± 0.67 s. We compare statistics of the simulated QPPs with parameters of the host flares and discuss the impacts of flare properties on the periods of QPPs. Considering the intrinsic characteristic of CA models, namely the repetitive load/unload mechanism, and the obtained pieces of evidence, we suggest that CA models may generate QPPs. We also examine the applicability of autoregressive integrated moving average models to describe the simulated and observed QPPs.

Keywords: Lomb-Scargle periodogram, Solar flares, Solar magnetic reconnection, Time series analysis
Detailed Accretion History of the Supermassive Black Hole in NGC 5972 over the Past ≳10<SUP>4</SUP> yr through the Extended Emission-line Region. We present integral field spectroscopic observations of NGC 5972 obtained with the Multi-Unit Spectroscopic Explorer at the Very Large Telescope. NGC 5972 is a nearby galaxy containing both an active galactic nucleus (AGN) and an extended emission-line region (EELR) reaching out to ~17 kpc from the nucleus. We analyze the physical conditions of the EELR using spatially resolved spectra, focusing on the radial dependence of ionization state together with the light-travel time distance to probe the variability of the AGN on ≳104 yr timescales. The kinematic analysis suggests multiple components: (a) a faint component following the rotation of the large-scale disk, (b) a component associated with the EELR suggestive of extraplanar gas connected to tidal tails, and (c) a kinematically decoupled nuclear disk. Both the kinematics and the observed tidal tails suggest a major past interaction event. Emission-line diagnostics along the EELR arms typically evidence Seyfert-like emission, implying that the EELR was primarily ionized by the AGN. We generate a set of photoionization models and fit these to different regions along the EELR. This allows us to estimate the bolometric luminosity required at different radii to excite the gas to the observed state. Our results suggest that NGC 5972 is a fading quasar, showing a steady gradual decrease in intrinsic AGN luminosity, and hence the accretion rate onto the SMBH, by a factor ~100 over the past 5 × 104 yr.

Keywords: AGN host galaxies, Active galactic nuclei
Quasars with Periodic Variability: Capabilities and Limitations of Bayesian Searches for Supermassive Black Hole Binaries in Time-domain Surveys. Supermassive black hole binaries (SMBHBs) are an inevitable consequence of galaxy mergers. At sub-parsec separations, they are practically impossible to resolve, and the most promising technique is to search for quasars with periodic variability. However, searches for quasar periodicity in time-domain data are challenging due to the stochastic variability of quasars. In this paper, we used Bayesian methods to disentangle periodic SMBHB signals from intrinsic damped random walk (DRW) variability in active galactic nuclei light curves. We simulated a wide variety of realistic DRW and DRW+sine light curves. Their observed properties are modeled after the Catalina Real-time Transient Survey (CRTS) and expected properties of the upcoming Legacy Survey of Space and Time (LSST) from the Vera C. Rubin Observatory. Through a careful analysis of parameter estimation and Bayesian model selection, we investigated the range of parameter space for which binary systems can be detected. We also examined which DRW signals can mimic periodicity and be falsely classified as binary candidates. We found that periodic signals are more easily detectable if the period is short or the amplitude of the signal is large compared to the contribution of the DRW noise. We saw similar detection rates both in the CRTS and LSST-like simulations, while the false-detection rate depends on the quality of the data and is minimal in LSST. Our idealized simulations provide an excellent way to uncover the intrinsic limitations in quasar periodicity searches and set the stage for future searches for SMBHBs.

Keywords: Supermassive black holes, Active galactic nuclei
Modeling the Luminosity-dependent Pulse Profile and Emission Geometry of SMC X-2 during a Giant Outburst. One of the brightest X-ray pulsars in the Small Magellanic Cloud is SMC X-2. During its most recent major outburst in 2015, this transient pulsar displayed significant changes in both its accretion state and magnetosphere, particularly when it entered the low-luminosity regime of subcritical accretion. Polestar is a pulse-profile modeling code that helps in delineating the geometry of the emission as the source evolves past outburst and toward lower-luminosity states. Applying Polestar to XMM-Newton and NuSTAR pulse profiles, we constrained the most likely inclination of the spin axis of the pulsar to be i = 87° ± 4°. As the X-ray luminosity declined, an increase in the pulsed fraction was detected from Swift observations, which suggests a transition from fan- to pencil-beam emission during the later stages of the outburst. Additionally, we also performed analysis of the OGLE IV light curves, which showed strong modulation in the optical profiles during the outburst.

Keywords: Small Magellanic Cloud, Accretion, High mass x-ray binary stars, Pulsars
Interpreting the Observed Positive Correlation between the Event-integrated Fluence and the Rollover Energy of Solar Energetic Particle Events by the PAMELA Mission with Coupled Hydromagnetic Wave Excitation and Proton Acceleration at Shocks in the Low Corona. An analytical model for diffusive shock acceleration (DSA) at one-dimensional stationary planar shocks in the lower corona is presented. The model introduces an upstream escape boundary through which a constant flux of protons streaming upstream out of the system is allowed. The nonvanishing flux of streaming protons out of the system limits the maximum attainable energy of DSA and produces a rollover in the high-energy spectra of the shock-accelerated protons. The condition for the rollover energy derived from the model can account for the approximately linear relation between the natural logarithm of event-integrated fluences and the natural logarithm of rollover energies as demonstrated in Bruno et al. Solar energetic particle (SEP) events with higher integrated fluences in principle exhibit higher rollover energies since proton-excited hydromagnetic waves in the turbulent sheath reduce the proton diffusion coefficient and throttle the upstream streaming of protons. The consistency between the observation and the theory of DSA at shocks in the lower corona serves as evidence for the shock origin of protons of the highest energies in large SEP events.

Keywords: Solar energetic particles, Solar coronal mass ejection shocks, Solar particle emission
Extragalactic Magnetism with SOFIA (SALSA Legacy Program). IV. Program Overview and First Results on the Polarization Fraction. We present the first data release of the Survey on extragALactic magnetiSm with SOFIA (SALSA Legacy Program) with a set of 14 nearby (&lt;20 Mpc) galaxies with resolved imaging polarimetric observations using HAWC+ from 53 to 214 μm at a resolution of 5″-18″ (90 pc-1 kpc). We introduce the definitions of and background on extragalactic magnetism and present the scientific motivation and sample selection of the program. Here we focus on the general trends in the emissive polarization fraction. Far-infrared polarimetric observations trace the thermal polarized emission of magnetically aligned dust grains across the galaxy disks with polarization fractions of P = 0%-15% in the cold, T d = [19, 48] K, and dense, ${\mathrm{log}}_{10}({N}_{{\rm{H}}{\rm\small{I}}+{{\rm{H}}}_{2}}[{\mathrm{cm}}^{-2}])=[19.96,22.91]$ , interstellar medium. The spiral galaxies show a median &lt;P 154 μm&gt; = 3.3% ± 0.9% across the disks. We report the first polarized spectrum of starburst galaxies showing a minimum within 89-154 μm. The falling 53-154 μm polarized spectrum may be due to a decrease in the dust grain alignment efficiency produced by variations in dust temperatures along the line of sight in the galactic outflow. We find that the starburst galaxies and the star-forming regions within normal galaxies have the lowest polarization fractions. We find that 50% (seven out of 14) of the galaxies require a broken power law in the P - ${N}_{{\rm{H}}{\rm\small{I}}+{{\rm{H}}}_{2}}$ and P - T d relations with three different trends. Group 1 has a relative increase of anisotropic random B-fields produced by compression or shear of B-fields in the galactic outflows, starburst rings, and inner bars of galaxies, and groups 2 and 3 have a relative increase of isotropic random B-fields driven by star-forming regions in the spiral arms and/or an increase of dust grain alignment efficiency caused by shock-driven regions or evolutionary stages of a galaxy. *SALSA provides a software repository at https://github.com/galmagfields/hawc and publicly available data at http://galmagfields.com/.

Keywords: Interstellar dust, Starburst galaxies, Spiral galaxies, Far infrared astronomy, Active galactic nuclei, Star formation, Interstellar medium, Polarimetry, Extragalactic magnetic fields
Using Bayesian Deep Learning to Infer Planet Mass from Gaps in Protoplanetary Disks. Planet-induced substructures, like annular gaps, observed in dust emission from protoplanetary disks, provide a unique probe for characterizing unseen young planets. While deep-learning-based models have an edge in characterizing a planet's properties over traditional methods, such as customized simulations and empirical relations, they lacks the ability to quantify the uncertainties associated with their predictions. In this paper, we introduce a Bayesian deep-learning network, "DPNNet-Bayesian," which can predict planet mass from disk gaps and also provides the uncertainties associated with the prediction. A unique feature of our approach is that it is able to distinguish between the uncertainty associated with the deep-learning architecture and the uncertainty inherent in the input data due to measurement noise. The model is trained on a data set generated from disk-planet simulations using the FARGO3D hydrodynamics code, with a newly implemented fixed grain size module and improved initial conditions. The Bayesian framework enables the estimation of a gauge/confidence interval over the validity of the prediction, when applied to unknown observations. As a proof of concept, we apply DPNNet-Bayesian to the dust gaps observed in HL Tau. The network predicts masses of 86.0 ± 5.5 M ⊕, 43.8 ± 3.3 M ⊕, and 92.2 ± 5.1 M ⊕, respectively, which are comparable to those from other studies based on specialized simulations.

Keywords: Exoplanet detection methods, Bayesian statistics, Protoplanetary disks, Neural networks