Sazuna/UAT_keywords huggingface dataset:
Pulse Profile Variations Associated with Two Glitches of PSR B1822-09. We reported two new glitches of PSR B1822-09 that were detected at the Shanghai Tian Ma Radio Telescope. The glitches occurred around MJD 58,025 and 58,474.5, respectively. The shapes of the integrated mean pulse profiles in both the radio-bright (B-mode) and the radio-quiet (Q-mode) modes changed after two glitches. Such changes are probably related to the trigger mechanisms of the glitches. According to the Gaussian fitting to the integrated mean pulse profiles, variations of the integrated mean pulse profiles can be attributed to variations of the Gaussian components. The fitting also indicates that there may be changes in only a part of the Gaussian components after glitches. We proposed an interpretation of the relation between the precursor and the interpulse of PSR B1822-09 according to variations of Gaussian components. We analyzed the cumulative distributions of the glitch sizes and the waiting times of all 14 glitches of PSR B1822-09. The cumulative distribution of the glitch sizes can be fitted well by a power law with an index α of 0.985 ± 0.005. The cumulative distribution of the waiting times follows a Poisson model with a mean waiting time λ of 466 ± 66 days. The correlation coefficient between the waiting times and the sizes of the corresponding preceding glitches is 0.906. In contrast, there is no apparent correlation between the waiting times and the sizes of the corresponding trailing glitches.

Keywords: Neutron stars, Pulsars
Three-dimensional General-relativistic Simulations of Neutrino-driven Winds from Rotating Proto-neutron Stars. We explore the effects of rapid rotation on the properties of neutrino-heated winds from proto-neutron stars (PNS) formed in core-collapse supernovae or neutron-star mergers by means of three-dimensional general-relativistic hydrodynamical simulations with M0 neutrino transport. We focus on conditions characteristic of a few seconds into the PNS cooling evolution when the neutrino luminosities obey ${L}_{{\nu }_{e}}+{L}_{{\bar{\nu }}_{e}}\approx 7\times {10}^{51}$ erg s-1, and over which most of the wind mass loss will occur. After an initial transient phase, all of our models reach approximately steady-state outflow solutions with positive energies and sonic surfaces captured on the computational grid. Our nonrotating and slower rotating models (angular velocity relative to Keplerian Ω/ΩK ≲ 0.4; spin period P ≳ 2 ms) generate approximately spherically symmetric outflows with properties in good agreement with previous PNS wind studies. By contrast, our most rapidly spinning PNS solutions (Ω/ΩK ≳ 0.75; P ≈ 1 ms) generate outflows focused in the rotational equatorial plane with much higher mass-loss rates (by over an order of magnitude), lower velocities, lower entropy, and lower asymptotic electron fractions, than otherwise similar nonrotating wind solutions. Although such rapidly spinning PNS are likely rare in nature, their atypical nucleosynthetic composition and outsized mass yields could render them important contributors of light neutron-rich nuclei compared to more common slowly rotating PNS birth. Our calculations pave the way to including the combined effects of rotation and a dynamically important large-scale magnetic field on the wind properties within a three-dimensional GRMHD framework.

Keywords: Neutron stars, High energy astrophysics, R-process, Supernova remnants, Stellar winds, General relativity
The Solar Wind Parker Spiral Angle Distributions and Variations at 1 au. Using the data from the Advanced Composition Explorer (ACE) and Wind spacecraft, we statistically studied the Parker spiral angle (PSA) of the solar wind magnetic field from 1998 to 2019 at 1 au. The PSA occurrences over both a Carrington rotation (CR) and a year can be well fitted by a Gaussian distribution. However, large-scale magnetic structures, such as interplanetary coronal mass ejections (ICMEs), can significantly deviate the PSA distribution of a CR from the Gaussian distribution. The PSA distributions of each CR and each year are affected by the solar activity: They are more concentrated at a relatively higher average PSA at solar maximum. There is also a weak anticorrelation between the yearly solar wind speed (v sw) and the average PSA. MESSENGER, Venus Express, and ACE observations at different heliocentric distances within 1 au show that the dominating polarities of the heliospheric magnetic field change greatly from year to year even when the solar activity is on the same level. Our results suggest that the PSA distribution in addition to the sunspot number can provide some new information on the magnetic field variation of the Sun.

Keywords: Solar activity, Solar wind, Solar magnetic fields, Sunspots
Quasar Standardization: Overcoming Selection Biases and Redshift Evolution. Quasars (QSOs) are extremely luminous active galactic nuclei currently observed up to redshift z = 7.642. As such, they have the potential to be the next rung of the cosmic distance ladder beyond Type Ia supernovae, if they can reliably be used as cosmological probes. The main issue in adopting QSOs as standard candles (similarly to gamma-ray bursts) is the large intrinsic scatter in the relations between their observed properties. This could be overcome by finding correlations among their observables that are intrinsic to the physics of QSOs and not artifacts of selection biases and/or redshift evolution. The reliability of these correlations should be verified through well-established statistical tests. The correlation between the ultraviolet and X-ray fluxes developed by Risaliti &amp; Lusso is one of the most promising relations. We apply a statistical method to correct this relation for redshift evolution and selection biases. Remarkably, we recover the the same parameters of the slope and the normalization as Risaliti &amp; Lusso. Our results establish the reliability of this relation, which is intrinsic to the QSO properties and not merely an effect of selection biases or redshift evolution. Hence, the possibility to standardize QSOs as cosmological candles, thereby extending the Hubble diagram up to z = 7.54.

Keywords: Quasars
Gaia May Detect Hundreds of Well-characterized Stellar Black Holes. Detection of black holes (BHs) with detached luminous companions (LCs) can be instrumental in connecting the BH properties with their progenitors since the latter can be inferred from the observable properties of the LC. Past studies showed the promise of Gaia astrometry in detecting BH-LC binaries. We build on these studies by (1) initializing the zero-age binary properties based on realistic, metallicity-dependent star formation history in the Milky Way (MW); (2) evolving these binaries to current epoch to generate realistic MW populations of BH-LC binaries; (3) distributing these binaries in the MW, preserving the complex age-metallicity-Galactic position correlations; (4) accounting for extinction and reddening using three-dimensional dust maps; and (5) examining the extended Gaia mission's ability to resolve BH-LC binaries. We restrict ourselves to detached BH-LC binaries with orbital period P orb ≤ 10 yr such that Gaia can observe at least one full orbit. We find that (1) the extended Gaia mission can astrometrically resolve ~30-300 detached BH-LC binaries depending on our assumptions of supernova physics and astrometric detection threshold; (2) Gaia's astrometry alone can indicate BH candidates for ~10-100 BH-LC binaries by constraining the dark primary mass ≥3 M ⊙; and (3) distributions of observables, including orbital periods, eccentricities, and component masses, are sensitive to the adopted binary evolution model and hence can directly inform binary evolution models. Finally, we comment on the potential to further characterize these BH binaries through radial velocity measurements and observation of X-ray counterparts.

Keywords: X-ray binary stars, Stellar populations, Compact binary stars, Astrometric binary stars, Astrometry, Detached binary stars, X-ray sources, Astrophysical black holes, Stellar evolution
Bridging the Gap: Categorizing Gravitational-wave Events at the Transition between Neutron Stars and Black Holes. We search for features in the mass distribution of detected compact binary coalescences which signify the transition between neutron stars (NSs) and black holes (BHs). We analyze all gravitational-wave (GW) detections by the LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration (LVK) made through the end of the first half of the third observing run, and find clear evidence for two different populations of compact objects based solely on GW data. We confidently (99.3%) find a steepening relative to a single power law describing NSs and low-mass BHs below ${2.4}_{-0.5}^{+0.5}{M}_{\odot }$ , which is consistent with many predictions for the maximum NS mass. We find suggestions of the purported lower mass gap between the most massive NSs and the least massive BHs, but are unable to conclusively resolve it with current data. If it exists, we find the lower mass gap's edges to lie at ${2.2}_{-0.5}^{+0.7}{M}_{\odot }$ and ${6.0}_{-1.4}^{+2.4}{M}_{\odot }$ . We reexamine events that have been deemed "exceptional" by the LVK collaborations in the context of these features. We analyze GW190814 self-consistently in the context of the full population of compact binaries, finding support for its secondary to be either a NS or a lower mass gap object, consistent with previous claims. Our models are the first to accommodate this event, which is an outlier with respect to the binary BH population. We find that GW200105 and GW200115 probe the edges of, and may have components within, the lower mass gap. As future data improve global population models, the classification of these events will also improve.

Keywords: Neutron stars, Black holes, Gravitational wave sources, Gravitational wave astronomy, Nuclear astrophysics, Gravitational waves, Compact objects, LIGO, Astrophysical black holes
Deep Simultaneous Limits on Optical Emission from FRB 20190520B by 24.4 fps Observations with Tomo-e Gozen. We conduct 24.4 fps optical observations of repeating fast radio burst (FRB) 20190520B using Tomo-e Gozen, a high-speed CMOS camera mounted on the Kiso 105 cm Schmidt telescope, simultaneously with radio observations carried out using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We succeeded in the simultaneous optical observations of 11 radio bursts that FAST detected. However, no corresponding optical emission was found. The optical fluence limits as deep as 0.068 Jy ms are obtained for the individual bursts (0.029 Jy ms on the stacked data) corrected for the dust extinction in the Milky Way. The fluence limit is deeper than those obtained in the previous simultaneous observations for an optical emission with a duration ≳0.1 ms. Although the current limits on radio-optical spectral energy distribution (SED) of FRBs are not constraining, we show that SED models based on observed SEDs of radio variable objects such as optically detected pulsars, and a part of parameter spaces of theoretical models in which FRB optical emission is produced by inverse Compton scattering in a pulsar magnetosphere or a strike of a magnetar blastwave into a hot wind bubble, can be ruled out once a similar fluence limit as in our observation is obtained for a bright FRB with a radio fluence ≳5 Jy ms.

Keywords: Optical observation, Time domain astronomy, Radio transient sources
The Effects of Circumstellar Dust Scattering on the Light Curves and Polarizations of Type Ia Supernovae. Observational signatures of the circumstellar material (CSM) around Type Ia supernovae (SNe Ia) provide a unique perspective on their progenitor systems. The pre-supernova evolution of the SN progenitors may naturally eject CSM in most of the popular scenarios of SN Ia explosions. In this study, we investigate the influence of dust scattering on the light curves and polarizations of SNe Ia. A Monte Carlo method is constructed to numerically solve the process of radiative transfer through the CSM. Three types of geometric distributions of the CSM are considered: spherical shell, axisymmetric disk, and axisymmetric shell. We show that both the distance of the dust from the SN and the geometric distribution of the dust affect the light curve and color evolutions of SN. We found that the geometric location of the hypothetical circumstellar dust may not be reliably constrained based on photometric data alone, even for the best observed cases such as SN 2006X and SN 2014J, due to the degeneracy of CSM parameters. Our model results show that a time sequence of broadband polarimetry with appropriate time coverage from a month to about one year after explosion can provide unambiguous limits on the presence of circumstellar dust around SNe Ia. *Supported by the National Natural Science Foundation of China.

Keywords: Light curves, Type Ia supernovae
Nodal Precession and Tidal Evolution of Two Hot Jupiters: WASP-33 b and KELT-9 b. Hot Jupiters orbiting rapidly rotating stars on inclined orbits undergo tidally induced nodal precession measurable over several years of observations. The Hot Jupiters WASP-33 b and KELT-9 b are particularly interesting targets because they are among the hottest planets found to date, orbiting relatively massive stars. Here, we analyze archival and new data that span 11 and 5 yr for WASP-33 b and KELT-9 b, respectively, in order to model and improve upon their tidal precession parameters. Our work confirms the nodal precession for WASP-33 b and presents the first clear detection of the precession of KELT-9 b. We determine that WASP-33 and KELT-9 have gravitational quadrupole moments $({6.3}_{-0.8}^{+1.2})\times {10}^{-5}$ and $({3.26}_{-0.80}^{+0.93})\times {10}^{-4}$ , respectively. We estimate the planets' precession periods to be ${1460}_{-130}^{+170}$ yr and ${890}_{-140}^{+200}$ yr, respectively, and that they will cease to transit their host stars around the years ${2090}_{-10}^{+17}$ CE and ${2074}_{-10}^{+12}$ CE, respectively. Additionally, we investigate both planets' tidal and orbital evolution, suggesting that a high-eccentricity tidal migration scenario is possible to produce both system architectures and that they will most likely not be engulfed by their hosts before the end of their main-sequence lifetimes.

Keywords: Transits, Hot Jupiters, Exoplanets, Orbital nodes, Tidal interaction
GRB 210121A: Observation of Photospheric Emissions from Different Regimes and the Evolution of the Outflow. GRB 210121A was observed by Insight-HXMT, by the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM), and by the Fermi Gamma-ray Burst Monitor (Fermi/GBM) on 2021 January 21. In this work, photospheric emission from a structured jet is preferred to interpret the prompt emission phase of GRB 210121A, and emissions from different regimes are observed on-axis. Particularly, the emission from the intermediate photosphere is first observed in the first 1.3 s of the prompt emission, while emissions from the other part are dominant by the emissions from the saturated regime. This offers an alternative explanation compared with previous work. Moreover, the emissions that consider the intermediate photosphere can well interpret the changes in the low-energy photon index α during the pulses. In addition, the evolution of the outflow is extracted from a time-resolved analysis, and a correlation of ${{\rm{\Gamma }}}_{0}\propto {L}_{0}^{0.25\pm 0.5}$ is obtained, which implies that the jet may be mainly launched by neutrino annihilation in a hyper-accretion disk.

Keywords: Gamma-ray bursts
Factors That Determine the Power-law Index of an Energy Distribution of Solar Flares. The power-law index of an occurrence frequency distribution of flares as a function of energy is one of the most important indicators to evaluate the contribution of small-scale flares to coronal heating. For a few decades, many studies tried to derive the power-law index using various instruments and methods. However, these results are various and the cause of this uncertainty is unknown due to the variety of observation conditions. Therefore, we investigated the dependence of the index on the solar activity, coronal features, released energy range, and active region properties such as magnetic flux, twist, and size. Our findings are (1) annual power-law index derived from time series of total solar irradiance (Sun-as-a-star observation analysis) has a negative correlation with sunspot number; (2) power-law index in active region is smaller than that of the quiet Sun and coronal holes; (3) power-law index is almost constant in the energy range of 1025 ≲ E ≲ 1030 erg; and (4) active regions that have more magnetic free energy density, unsigned magnetic flux, and shear angle tend to have smaller power-law indices. Based on the results and energy-scaling law of Petschek-type reconnection, we suggest that the power-law index of sunspot-scale events is smaller than that of granule-scale events. Moreover, we indicated that sunspot-scale events follow CSHKP flare model whereas granule-scale events follow Parker's nanoflare model.

Keywords: Solar flares, Solar coronal heating, Solar active regions, Solar physics, Solar corona, Solar activity
An Improved GPU-based Ray-shooting Code for Gravitational Microlensing. We present an improved inverse-ray-shooting code based on graphics processing units (GPUs) to generate microlensing magnification maps. In addition to introducing GPUs to accelerate the calculations, we also invest effort into two aspects: (i) A standard circular lens plane is replaced by a rectangular one to reduce the number of unnecessary lenses as a result of an extremely prolate rectangular image plane. (ii) An interpolation method is applied in our implementation, achieving significant acceleration when dealing with the large number of lenses and light rays required by high-resolution maps. With these applications, we have greatly reduced the running time while maintaining high accuracy: The speed was increased by about 100 times compared with an ordinary GPU-based inverse-ray-shooting code and a GPU-D code when handling a large number of lenses. If a high-resolution situation with up to 10,0002 pixels, resulting in almost 1011 light rays, is encountered, the running time can also be reduced by two orders of magnitude.

Keywords: Gravitational microlensing, Gravitational lensing
Formation of the SDC13 Hub-filament System: A Cloud-Cloud Collision Imprinted on the Multiscale Magnetic Field. Hub-filament systems (HFSs) are potential sites of protocluster and massive star formation, and play a key role in mass accumulation. We report JCMT POL-2 850 μm polarization observations toward the massive HFS SDC13. We detect an organized magnetic field near the hub center with a cloud-scale "U-shape" morphology following the western edge of the hub. Together with larger-scale APEX 13CO and PLANCK polarization data, we find that SDC13 is located at the convergent point of three giant molecular clouds (GMCs) along a large-scale, partially spiral-like magnetic field. The smaller "U-shape" magnetic field is perpendicular to the large-scale magnetic field and the converging GMCs. We explain this as the result of a cloud-cloud collision. Within SDC13, we find that local gravity and velocity gradients point toward filament ridges and hub center. This suggests that gas can locally be pulled onto filaments and overall converges to the hub center. A virial analysis of the central hub shows that gravity dominates the magnetic and kinematic energy. Combining large- and small-scale analyses, we propose that SDC13 is initially formed from a collision of clouds moving along the large-scale magnetic field. In the post-shock regions, after the initial turbulent energy has dissipated, gravity takes over and starts to drive the gas accretion along the filaments toward the hub center.

Keywords: Interstellar filaments, Interstellar dynamics, Infrared dark clouds, Star forming regions, Molecular clouds, Interstellar magnetic fields, Giant molecular clouds, Star formation, Interstellar medium, Submillimeter astronomy, Polarimetry, Collapsing clouds
Mixed-mode Asteroseismology of Red Giant Stars Through the Luminosity Bump. Most current models of low-mass red giant stars do not reproduce the observed position of the red giant branch luminosity bump, a diagnostic of the maximum extent of the convective envelope during the first dredge up. Global asteroseismic parameters, the large frequency separation and frequency of maximum oscillation power, measured for large samples of red giants, show that modeling convective overshoot below the convective envelope helps match the modeled luminosity bump positions to observations; however, these global parameters cannot be used to probe envelope overshoot in a star-by-star manner. Red giant mixed modes, which behave like acoustic modes at the surface and like gravity modes in the core, contain important information about the interior structure of the star, especially near the convective boundary. Therefore, these modes may be used to probe interior processes, such as overshoot. Using a grid of red giant models with varying mass, metallicity, surface gravity, overshoot treatment, and amount of envelope overshoot, we find that changing the overshoot amplitude (and prescription) of overshoot below the convection zone in red giant stellar models results in significant differences in the evolution of the models' dipole mixed-mode oscillation frequencies, the average mixed-mode period spacing (&lt;ΔP&gt;), and gravity-mode phase offset term (ϵ  g ).

Keywords: Red giant branch, Stellar evolution, Stellar physics, Asteroseismology, Red giant bump
Simulating Solar Near-surface Rossby Waves by Inverse Cascade from Supergranule Energy. Rossby waves are found at several levels in the Sun, most recently in its supergranule layer. We show that Rossby waves in the supergranule layer can be excited by an inverse cascade of kinetic energy from the nearly horizontal motions in supergranules. We illustrate how this excitation occurs using a hydrodynamic shallow-water model for a 3D thin rotating spherical shell. We find that initial kinetic energy at small spatial scales inverse cascades quickly to global scales, exciting Rossby waves whose phase velocities are similar to linear Rossby waves on the sphere originally derived by Haurwitz. Modest departures from the Haurwitz formula originate from nonlinear finite amplitude effects and/or the presence of differential rotation. Like supergranules, the initial small-scale motions in our model contain very little vorticity compared to their horizontal divergence, but the resulting Rossby waves are almost all vortical motions. Supergranule kinetic energy could have mainly gone into gravity waves, but we find that most energy inverse cascades to global Rossby waves. Since kinetic energy in supergranules is three or four orders of magnitude larger than that of the observed Rossby waves in the supergranule layer, there is plenty of energy available to drive the inverse-cascade mechanism. Tachocline Rossby waves have previously been shown to play crucial roles in causing seasons of space weather through their nonlinear interactions with global flows and magnetic fields. We briefly discuss how various Rossby waves in the tachocline, convection zone, supergranule layer, and corona can be reconciled in a unified framework.

Keywords: Solar physics, Solar photosphere, Solar motion