Sazuna/UAT_keywords huggingface dataset:
Broadband X-Ray Timing and Spectral Characteristics of the Accretion-powered Millisecond X-Ray Pulsar MAXIJ1816-195. We studied the broadband X-ray timing and spectral behaviors of the newly confirmed accreting millisecond X-ray pulsar MAXI J1816-195 during its 2022 outburst. We used data from the Insight-HXMT Medium Energy (ME) and High Energy (HE) telescopes, NICER, and NuSTAR that cover the energy range between 0.8 and 210 keV. A coherent timing analysis of solely the Insight-HXMT HE data across the full outburst revealed a complex behavior of the timing residuals, also prominently visible in the independent Insight-HXMT ME and NICER data, particularly at the rising part of the outburst and at the very end in the NICER data. Therefore, we broke down the full outburst into a (noisy) rising part, covering only about five days, from MJD 59737.0 to 59741.9, and a decaying part, lasting for 19 days across MJD 59741.9-59760.6. Fitting for the decaying part, a timing model including a frequency ν and frequency time derivative $\dot{\nu }$ component yielded a value of (+9.0 ± 2.1) × 10-14 Hz s-1 for $\dot{\nu }$ , which could be interpreted as a spinup under our model assumptions. We detected X-ray pulsations up to ~95 keV in a combination of Insight-HXMT HE observations. The pulse profiles were quite stable over the whole outburst and could be well described by a truncated Fourier series using two harmonics, the fundamental and the first overtone. Both components kept alignment in the range 0.8-64 keV. The joint and time-averaged NICER and Insight-HXMT spectra in the energy range 1-150 keV were well fitted by the absorbed Comptonization model compps plus disk blackbody with two additional Gaussian components. Using the bolometric flux and spinup values both evaluated during the decay phase, we determined a magnetic field strength of (0.2-2) × 108 G for MAXI J1816-195.

Keywords: Neutron stars, Millisecond pulsars
SN 2022joj: A Peculiar Type Ia Supernova Possibly Driven by an Asymmetric Helium-shell Double Detonation. We present observations of SN 2022joj, a peculiar Type Ia supernova discovered by the Zwicky Transient Facility. SN 2022joj exhibits an unusually red g ZTF - r ZTF color at early times and a rapid blueward evolution afterward. Around maximum brightness, SN 2022joj shows a high luminosity ( ${M}_{{g}_{\mathrm{ZTF}},\max }\simeq -19.7$ mag), a blue broadband color (g ZTF - r ZTF ≃ -0.2 mag), and shallow Si II absorption lines, consistent with those of overluminous, SN 1991T-like events. The maximum-light spectrum also shows prominent absorption around 4200 Å, which resembles the Ti II features in subluminous, SN 1991bg-like events. Despite the blue optical-band colors, SN 2022joj exhibits extremely red ultraviolet minus optical colors at maximum luminosity (u - v ≃ 0.6 mag and uvw1 - v ≃ 2.5 mag), suggesting a suppression of flux at ~2500-4000 Å. Strong C II lines are also detected at peak. We show that these unusual spectroscopic properties are broadly consistent with the helium-shell double detonation of a sub-Chandrasekhar mass (M ≃ 1 M ☉) carbon/oxygen white dwarf from a relatively massive helium shell (M  s  ≃ 0.04-0.1 M ☉), if observed along a line of sight roughly opposite to where the shell initially detonates. None of the existing models could quantitatively explain all the peculiarities observed in SN 2022joj. The low flux ratio of [Ni II] λ7378 to [Fe II] λ7155 emission in the late-time nebular spectra indicates a low yield of stable Ni isotopes, favoring a sub-Chandrasekhar mass progenitor. The significant blueshift measured in the [Fe II] λ7155 line is also consistent with an asymmetric chemical distribution in the ejecta, as is predicted in double-detonation models.

Keywords: Observational astronomy, Surveys, White dwarf stars, Type Ia supernovae, Supernovae
Spatially Resolved Temperature and Density Structures of Nearby H II Regions. Photoionization models frequently assume constant temperature or density within H II regions. We investigate this assumption by measuring the detailed temperature and density structures of four H II regions in the Large Magellanic Cloud and the Small Magellanic Cloud, using integral-field spectroscopic data from the Wide-Field Spectrograph on the ANU 2.3 m telescope. We analyze the distribution of emission lines of low-ionization, intermediate-ionization, and high-ionization species. We present the complex electron temperature and density structures within H II regions. All four nebulae present a negative gradient in the electron density profile. Both positive and negative temperature gradients are observed in the nebulae. We create a series of nebula models with constant interstellar medium (ISM) pressure and varying temperature and density distributions. A comparison of the line ratios between our H II regions and models suggests that none of the simple nebula models can reproduce the observed temperature and density structures. Comparison between the models and the data suggests that the ISM pressure of nebulae in the LMC and SMC is between log(P/k) = 6 and 7.5. Complex internal structures of the nebulae highlight the importance of future Monte Carlo photoionization codes for accurate nebula modeling, which include a comprehensive consideration of arbitrary geometries of H II regions.

Keywords: H II regions
Cosmological Parameter Constraints from the SDSS Density and Momentum Power Spectra. We extract the galaxy density and momentum power spectra from a subset of early-type galaxies in the Sloan Digital Sky Survey (SDSS) DR7 main galaxy catalog. Using galaxy distance information inferred from the improved fundamental plane described in Yoon and Park, we reconstruct the peculiar velocities of the galaxies and generate number density and density-weighted velocity fields, from which we extract the galaxy density and momentum power spectra. We compare the measured values to the theoretical expectation of the same statistics, assuming an input Λ cold dark matter (CDM) model and using a third-order perturbative expansion. After validating our analysis pipeline with a series of mock data sets, we apply our methodology to the SDSS data and arrive at constraints $f{\sigma }_{8}={0.471}_{-0.080}^{+0.077}$ and ${b}_{1}{\sigma }_{8}={0.920}_{-0.070}^{+0.070}$ at a mean redshift $\bar{z}=0.04$ . Our result is consistent with the Planck cosmological best-fit parameters for the ΛCDM model. The momentum power spectrum is found to be strongly contaminated by small-scale velocity dispersion, which suppresses power by $\sim { \mathcal O }(30 \% )$ on intermediate scales k ~ 0.05 h Mpc-1.

Keywords: Cosmological parameters, Observational cosmology, Large-scale structure of the universe
Solar Radio Spectro-polarimeter (50-500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole Antenna. The Zeeman effect has been routinely used to image and quantify the solar photospheric magnetic field (B). Such a direct measuring technique is not yet available for the corona (Lin et al. 2004). Since almost all transient nonthermal radio emissions from the corona are either partially or fully circularly polarized, observing their polarization signatures over broad frequency ranges would be of help to estimate B as a function of heliocentric height. This article aims to describe the design and development of a Cross-polarized Log-Periodic Dipole Antenna (CLPDA), an integral part of a radio spectro-polarimeter, which works in the 50-500 MHz frequency-range and to explain the tests that were carried out to characterize it. The above frequency range corresponds to a heliocentric height range ≈1.03 &lt; r &lt; 2.5 R ⊙ (R ⊙ = photospheric radius), wherein the numerous coronal nonthermal transients associated with space-weather effects are observed to originate. The CLPDA is used to determine the strength and sense of polarization of the received radio signal. The uncertainty involved in the determination depends on the polarization-isolation (PI) between the two orthogonal components of a CLPDA. Some of the recent advancements made in the antenna design concepts at high frequencies (~GHz) were adopted to reduce the PI at low frequencies (~MHz). Throughout the above frequency range, the CLPDA has a gain, return loss, and PI of ≈6.6 dBi, ≲-10 dB, and ≲-27 dB, respectively. The average PI of the CLPDA varies from -30 to -24 dB over an azimuthal angle range 0° to ±45° within which the observations are performed regularly.

Keywords: Solar radio telescopes, Radio spectroscopy, Spectropolarimetry, Solar radio emission, Solar magnetic fields, Solar corona, Active solar corona, Solar-terrestrial interactions
The Stability of Some Galaxy Disks is Still Perplexing. The problem of how some disk galaxies avoid forming bars remains unsolved. Many galaxy models having reasonable properties continue to manifest vigorous instabilities that rapidly form strong bars and no widely accepted idea has yet been advanced to account for how some disk galaxies manage to avoid this instability. It is encouraging that not all galaxies formed in recent cosmological simulations possess bars, but the dynamical explanation for this result is unclear. The unstable mode that creates a bar is understood as a standing wave in a cavity that reflects off the disk center and the corotation radius, with amplification at corotation. Here we use simulations to address one further idea that may inhibit the feedback loop and therefore contribute to stability, which is to make the disk center dynamically hot and/or to taper away mass from the inner disk, which could be masked by a bulge. Unfortunately, we find that neither strategy makes much difference to the global stability of the disk in the models we have tried. While deep density cutouts do indeed prevent feedback through the center, they still reflect incoming waves and thereby provoke a slightly different instability that again leads to a strong bar.

Keywords: Galaxy dynamics, Galaxy structure, Galaxy evolution, Spiral galaxies
Σ<SUB>SFR</SUB>-M<SUB>∗</SUB> Diagram: A Valuable Galaxy Evolution Diagnostic to Complement (s)SFR-M<SUB>∗</SUB> Diagrams. The specific star formation rate (sSFR) is commonly used to describe the level of galaxy star formation (SF) and to select quenched galaxies. However, since it is a relative measure of the young-to-old population, an ambiguity in its interpretation may arise because a low sSFR can be due to either a substantial previous mass buildup or SF activity that is low. We show, using large samples spanning 0 &lt; z &lt; 2, that the normalization of the star formation rate (SFR) by the physical extent over which SF is taking place (i.e., the SFR surface density, ΣSFR) overcomes this ambiguity. ΣSFR has a strong physical basis, being tied to the molecular gas density and the effectiveness of stellar feedback, so we propose ΣSFR-M * as an important galaxy evolution diagram to complement (s)SFR-M * diagrams. Using the ΣSFR-M * diagram we confirm the Schiminovich et al. result that the level of SF along the main sequence today is only weakly mass-dependent-high-mass galaxies, despite their redder colors, are as active as blue, low-mass ones. At higher redshift, the slope of the "ΣSFR main sequence" steepens, signaling the epoch of bulge buildup in massive galaxies. We also find that ΣSFR based on the optical isophotal radius more cleanly selects both starbursting and spheroid-dominated (early-type) galaxies than the sSFR. One implication of our analysis is that the assessment of the inside-out versus outside-in quenching scenarios should consider both sSFR and ΣSFR radial profiles, because ample SF may be present in bulges with low sSFRs (red color).

Keywords: Galaxy quenching, Galaxy colors, Galaxy evolution, Galaxy radii
High-altitude Spider-type Prominence above the Magnetic Null Point. Rather unique observations of a high-altitude spider-type prominence in 2023 February are presented. The prominence or corresponding filament on the disk was not visible all the time but could appear and disappear in the course of a particular day. However, it persisted during the whole half of a solar rotation, being observable from day to day starting from the east limb of the Sun to the west limb. We show that the prominence was located in sagged coronal field lines just above a coronal magnetic null point. The presence of the null point and magnetic dips above it is confirmed by calculations of the potential magnetic field. The mass of the prominence apparently was appearing due to the condensation of hot coronal plasma after several eruptions that occurred in an active-region complex where the prominence was located. The prominence material flowed down along widely spread large coronal loops as coronal rain and was sometimes swept away by subsequent eruptions.

Keywords: Solar activity, Solar coronal loops, Solar filaments, Solar prominences
A Comprehensive Observational Study of the FRB 121102 Persistent Radio Source. FRB 121102 is the first fast radio burst to be spatially associated with a persistent radio source (QRS 121102), the nature of which remains unknown. We constrain the physical size of QRS 121102 by measuring its flux-density variability with the VLA from 12 to 26 GHz. Any such variability would likely be due to Galactic refractive scintillation and would require the source radius to be ≲1017 cm at the host-galaxy redshift. We found the radio variability to be lower than the scintillation theory predictions for such a small source, leaving open the possibility for non-AGN models for QRS 121102. In addition, we roughly estimated the mass of any potential supermassive black hole (BH) associated with QRS 121102 from the line width of the host-galaxy Hα emission using a new optical spectrum from the Keck Observatory. The line width indicates a supermassive BH mass of ≲104~5 M ⊙, too low for the observed radio luminosity and X-ray luminosity constraints, if QRS 121102 were an AGN. Finally, some dwarf galaxies that host supermassive BHs may be the stripped cores of massive galaxies during tidal interactions with companion systems. We find no nearby galaxy at the same redshift as the QRS 121102 host from low-resolution Keck spectra or the PanSTARRS catalog. In conclusion, we find no evidence supporting the hypothesis that QRS 121102 is an AGN. We instead argue that the inferred size and flat radio spectrum favor a plerion interpretation. We urge continued broadband radio monitoring of QRS 121102 to search for long-term evolution.

Keywords: Extragalactic radio sources, Radio bursts, High energy astrophysics, Radio transient sources
ALMA Gas-dynamical Mass Measurement of the Supermassive Black Hole in the Red Nugget Relic Galaxy PGC 11179. We present 0.″22-resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO(2-1) emission from the circumnuclear gas disk in the red nugget relic galaxy PGC 11179. The disk shows regular rotation, with projected velocities near the center of 400 km s-1. We assume the CO emission originates from a dynamically cold, thin disk and fit gas-dynamical models directly to the ALMA data. In addition, we explore systematic uncertainties by testing the impacts of various model assumptions on our results. The supermassive black hole (BH) mass (M BH) is measured to be M BH = (1.91 ± 0.04 [1σ statistical] ${}_{-0.51}^{+0.11}$ [systematic]) × 109 M ⊙, and the H-band stellar mass-to-light ratio M/L  H  = 1.620 ± 0.004 [1σ statistical] ${}_{-0.107}^{+0.211}$ [systematic] M ⊙/L ⊙. This M BH is consistent with the BH mass-stellar velocity dispersion relation but over-massive compared to the BH mass-bulge luminosity relation by a factor of 3.7. PGC 11179 is part of a sample of local compact early-type galaxies that are plausible relics of z ~ 2 red nuggets, and its behavior relative to the scaling relations echoes that of three relic galaxy BHs previously measured with stellar dynamics. These over-massive BHs could suggest that BHs gain most of their mass before their host galaxies do. However, our results could also be explained by greater intrinsic scatter at the high-mass end of the scaling relations, or by systematic differences in gas- and stellar-dynamical methods. Additional M BH measurements in the sample, including independent cross-checks between molecular gas- and stellar-dynamical methods, will advance our understanding of the co-evolution of BHs and their host galaxies.

Keywords: Supermassive black holes, Molecular gas, Astronomy data modeling, Millimeter astronomy, Extragalactic astronomy, Scaling relations, Galaxy kinematics, Galaxy circumnuclear disk, Submillimeter astronomy, Early-type galaxies
A Spectroscopic Survey of Lyα Emitters and Lyα Luminosity Function at Redshifts 3.7 and 4.8. We present a spectroscopic survey of Lyα emitters (LAEs) at z ~ 3.7 and z ~ 4.8. The LAEs are selected using the narrowband technique based on the combination of deep narrowband and broadband imaging data in two deep fields, and then spectroscopically confirmed with the MMT multifiber spectrograph Hectospec. The sample consists of 71 LAEs at z ~ 3.7 and 69 LAEs at z ~ 4.8 over ~1.5 deg2, making it one of the largest spectroscopically confirmed samples of LAEs at the two redshifts. Their Lyα luminosities are measured using the secure redshifts and deep photometric data, and span a range of ~1042.5-1043.6 erg s-1, so these LAEs represent the most luminous galaxies at the redshifts in terms of Lyα luminosity. We estimate and correct sample incompletenesses and derive reliable Lyα luminosity function (LFs) at z ~ 3.7 and 4.8 based on the two spectroscopic samples. We find that our Lyα LFs are roughly consistent (within a factor of 2-3) with previous measurements at similar redshifts that were derived from either photometric samples or spectroscopic samples. By comparing with previous studies in different redshifts, we find that the Lyα LFs decrease mildly from z ~ 3.1 to z ~ 5.7, supporting the previous claim of the slow LF evolution between z ~ 2 and z ~ 6. At z &gt; 5.7, the LF declines rapidly toward higher redshift, partly due to the effect of cosmic reionization.

Keywords: Lyman-alpha galaxies, High-redshift galaxies, Galaxy properties
The Rapid Optical Variability of the Nearby Radio-loud AGN Pictor A: Introducing the Quaver Pipeline for AGN Science with TESS. The sampling strategy of the Transiting Exoplanet Survey Satellite (TESS) makes TESS light curves extremely valuable for investigating the high cadence optical variability of active galactic nuclei (AGN). However, because the TESS instrument was primarily designed for exoplanet science, the use of the satellite for other applications requires careful treatment of the data. In this paper, we introduce Quaver, a new software tool designed specifically to extract TESS light curves of extended and faint sources presenting stochastic variability. We then use this new tool to extract light curves of the nearby radio-loud AGN Pictor A, and perform a temporal and power spectral analysis of its high-cadence optical variability. The obtained light curves are well fit with a damped random walk (DRW) model, exhibiting both stochastic AGN variations and flaring behavior. The DRW characteristic timescales are τ DRW ~ 3-6 days during more quiet periods, and τ DRW ~ 0.8 day for periods with strong flares, even when the flares themselves are masked from the DRW fit. The observed timescales are consistent with the dynamical, orbital, and thermal timescales expected for the low black hole mass of Pictor A.

Keywords: Radio active galactic nuclei, Active galactic nuclei, Astronomy software
Kinetic-scale Topological Structures Associated with Energy Dissipation in the Turbulent Reconnection Outflow. Assisted by the Magnetospheric Multiscale mission capturing unprecedented high-resolution data in the terrestrial magnetotail, we apply a local streamline-topology classification methodology to investigate the categorization of the magnetic field topological structures at kinetic scales in the turbulent reconnection outflow. It is found that strong correlations exist between the straining and rotational part of the velocity gradient tensor as well as the magnetic field gradient tensor. Strong energy dissipation prefers to occur at regions with high magnetic stress or current density, which is contributed mainly by O-type topologies. These results indicate that the kinetic structures with O-type topology play a more important role in energy dissipation in turbulent reconnection outflow.

Keywords: Space plasmas, Solar magnetic reconnection, Plasma physics, Interplanetary turbulence, Plasma astrophysics
Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT. We present multiwavelength observations by Chandrayaan-2/Solar X-ray Monitor, Solar Dynamics Observatory/Atmospheric Imaging Assembly, and Hinode/X-Ray Telescope (XRT) of a B-class flare observed on 2021 February 25, originating from an active region (AR 12804) near the northwest limb. The microflare lasts for ~30 minutes and is composed of hot loops reaching temperatures of 10 MK. We report excellent agreement (within 20%) for the average effective temperatures obtained at the flare peak from all the three instruments, which have different temperature sensitivities. The XRT filter combination of Be-thin and Be-med provides an excellent opportunity to measure the high temperatures in such microflare events. The elemental abundances during the evolution of the microflare are also studied and observed to drop toward photospheric values at the flare peak time, compared to coronal values during the rise and decay phase. This is consistent with previous XSM studies.

Keywords: Solar corona
The Third Fermi Large Area Telescope Catalog of Gamma-Ray Pulsars. We present 294 pulsars found in GeV data from the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. Another 33 millisecond pulsars (MSPs) discovered in deep radio searches of LAT sources will likely reveal pulsations once phase-connected rotation ephemerides are achieved. A further dozen optical and/or X-ray binary systems colocated with LAT sources also likely harbor gamma-ray MSPs. This catalog thus reports roughly 340 gamma-ray pulsars and candidates, 10% of all known pulsars, compared to ≤11 known before Fermi. Half of the gamma-ray pulsars are young. Of these, the half that are undetected in radio have a broader Galactic latitude distribution than the young radio-loud pulsars. The others are MSPs, with six undetected in radio. Overall, ≥236 are bright enough above 50 MeV to fit the pulse profile, the energy spectrum, or both. For the common two-peaked profiles, the gamma-ray peak closest to the magnetic pole crossing generally has a softer spectrum. The spectral energy distributions tend to narrow as the spindown power $\dot{E}$ decreases to its observed minimum near 1033 erg s‑1, approaching the shape for synchrotron radiation from monoenergetic electrons. We calculate gamma-ray luminosities when distances are available. Our all-sky gamma-ray sensitivity map is useful for population syntheses. The electronic catalog version provides gamma-ray pulsar ephemerides, properties, and fit results to guide and be compared with modeling results.

Keywords: Neutron stars, Rotation powered pulsars, Pulsar timing method, Millisecond pulsars, Radio pulsars, Pulsars, Celestial objects catalogs, Binary pulsars, Gamma-rays