Sazuna/UAT_keywords huggingface dataset:
Thermal and Nonthermal Emission from a Peculiar Long-duration GRB 211211A. Long-duration GRB 211211A that lacks a supernova emission even down to very stringent limits at such a low redshift z = 0.076 and is associated with kilonova emission, suggests that its physical origin is from a binary compact star merger. By reanalyzing its data observed with the Gamma-Ray Burst Monitor on board the Fermi mission, we find that both time-integrated and time-resolved spectra can be fitted well by using a 2SBPL plus blackbody (2SBPL+BB) model in the prompt emission. The bulk Lorentz factors (Γph) of the outflow can be inferred by invoking the observed thermal emission at the photosphere radius within a pure fireball model, and we find out that the temporal evolution of Γph seems to be tracking with the light curve. The derived values of Γph are also consistent with the Γph-L  γ,iso/E  γ,iso correlations that had been found in other bursts. Moreover, we also calculate the magnetization factor σ 0 in the central engine and σ ph at the photosphere radius within the framework of a hybrid jet model, and find that the values of both 1 + σ 0 and 1 + σ ph are larger than 1 for different time slices. It suggests that at least the Poynting-flux component is indeed existent in the outflow. If this is the case, one possible physical interpretation of thermal and nonthermal emissions in GRB 211211A is from the contributions of both $\nu \bar{\nu }$ annihilation and the Blandford-Znajek mechanisms in the relativistic jet when a stellar mass black hole resides in the central engine.

Keywords: Gamma-ray bursts
An Ap Star Catalog Based on LAMOST DR9. We present a sample of 2700 Ap stars in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR9 catalog. The candidates are first selected to be in a temperature range typical of Ap stars by using the BP - RP color index from Gaia DR3. Then the 5200 Å flux depression features characteristic of Ap stars are visually checked in LAMOST DR9 spectra. The detailed spectral features are given by applying a modified spectral classification program, MKCLASS. The stellar parameters of these Ap stars, such as the T eff, $\mathrm{log}g$ , [Fe/H], [Si/H], and $v\sin i$ , are either extracted from a hot star catalog or derived through empirical relations and then a statistical analysis is carried out. The evolutionary stages are also discussed. Finally, we discuss the rotation and pulsation features of those that have TESS or Kepler light curves. Among these Ap stars, we find seven new rotation variables, one new roAp star, and a new δ Scuti pulsation of a previously known roAp star.

Keywords: Ap stars, Astronomy data analysis, Chemical abundances, Variable stars, Chemically peculiar stars
The Formation of the Brightest Cluster Galaxy and Intracluster Light in Cosmological N-body Simulations with the Galaxy Replacement Technique. We investigate the formation channels of the intracluster light (ICL) and the brightest cluster galaxy (BCG) in clusters at z = 0. For this, we perform multi-resolution cosmological N-body simulations using the "galaxy replacement technique." We study the formation channels of the ICL and BCG as a function of distance from the cluster center and the dynamical state of the clusters at z = 0. To do this, we trace back the stars of the ICL and BCG, and identify the stellar components in which they existed when they first fell into the clusters. We find that the progenitors of the ICL and BCG in the central region of the cluster fell earlier and with a higher total mass ratio of the progenitors to the cluster compared to the outer region. This causes a negative radial gradient in the infall time and total mass ratio of the progenitors. Although stellar mass of the progenitors does not show the same radial gradient in all clusters, massive galaxies (M gal &gt; 1010 M ⊙ h-1) are the dominant formation channel of the ICL and BCG for all clusters, except for our most relaxed cluster. For clusters that are dynamically more unrelaxed, we find that the progenitors of the ICL and BCG fall into their clusters more recently, and with a higher mass and mass ratio. Furthermore, we find that the diffuse material of massive galaxies and group-mass halos that is formed by preprocessing contributes significantly to the ICL in the outer region of the unrelaxed clusters.

Keywords: Galaxy clusters, Galaxy formation, Galaxy evolution, Computational methods
Size and Spectroscopic Evolution of HectoMAP Quiescent Galaxies. The HectoMAP survey provides a complete, mass-limited sample of 30,231 quiescent galaxies with i-band Hyper Suprime-Cam Subaru Strategic Program (HSC SSP) imaging that spans the redshift range 0.2 &lt; z &lt; 0.6. We combine half-light radii based on HSC SSP imaging with redshifts and D  n 4000 to explore the size-mass relation, ${R}_{e}=A\times {M}_{* }^{\alpha }$ , and its evolution for the entire HectoMAP quiescent population and for two subsets of the data. Newcomers with 1.5 &lt; D  n 4000 &lt; 1.6 at each redshift show a steeper increase in A as the universe ages than the population that descends from galaxies that are already quiescent at the survey limit, z ~ 0.6 (the resident population). In broad agreement with previous studies, evolution in the size-mass relation both for the entire HectoMAP sample and for the resident population (but not for the newcomers alone) is consistent with minor merger driven growth. For the resident population, the evolution in the size-mass relation is independent of the population age at z ~ 0.6. The contrast between the sample of newcomers and the resident population provides insight into the role of commonly termed "progenitor bias" on the evolution of the size-mass relation.

Keywords: Quenched galaxies, Galaxy structure, Galaxy stellar content, Galaxy photometry, Galaxy evolution, Galaxy spectroscopy, Redshift surveys
When Spectral Modeling Meets Convolutional Networks: A Method for Discovering Reionization-era Lensed Quasars in Multiband Imaging Data. Over the last two decades, around 300 quasars have been discovered at z ≳ 6, yet only one has been identified as being strongly gravitationally lensed. We explore a new approach-enlarging the permitted spectral parameter space, while introducing a new spatial geometry veto criterion-which is implemented via image-based deep learning. We first apply this approach to a systematic search for reionization-era lensed quasars, using data from the Dark Energy Survey, the Visible and Infrared Survey Telescope for Astronomy Hemisphere Survey, and the Wide-field Infrared Survey Explorer. Our search method consists of two main parts: (i) the preselection of the candidates, based on their spectral energy distributions (SEDs), using catalog-level photometry; and (ii) relative probability calculations of the candidates being a lens or some contaminant, utilizing a convolutional neural network (CNN) classification. The training data sets are constructed by painting deflected point-source lights over actual galaxy images, to generate realistic galaxy-quasar lens models, optimized to find systems with small image separations, i.e., Einstein radii of θ E ≤ 1″. Visual inspection is then performed for sources with CNN scores of P lens &gt; 0.1, which leads us to obtain 36 newly selected lens candidates, which are awaiting spectroscopic confirmation. These findings show that automated SED modeling and deep learning pipelines, supported by modest human input, are a promising route for detecting strong lenses from large catalogs, which can overcome the veto limitations of primarily dropout-based SED selection approaches.

Keywords: Early universe, Supermassive black holes, Quasars, Strong gravitational lensing, Active galaxies, Active galactic nuclei, Gravitational lensing, Reionization, High-redshift galaxies
ALMA Resolves the First Strongly Lensed Optical/Near-IR-dark Galaxy. We present high-resolution (≲0.″1) Atacama Large Millimeter/submillimeter Array observations of the strongly lensed galaxy HATLASJ113526.2-01460 at redshift z ∼ 3.1, discovered in the GAMA 12th field of the Herschel-ATLAS survey. This gravitationally lensed system is remarkably peculiar, in that neither the background source nor the foreground lens show a clearly detected optical/near-IR Hubble Space Telescope-J band emission. We perform accurate lens modeling and source morphology reconstruction in three different (sub)millimeter continuum bands and in the C[II] and CO(8−7) spectral lines. The modeling indicates a foreground lensing (likely elliptical) galaxy with mass ≳1011 M ⊙ at z ≳ 1.5, while the source (sub)millimeter continuum and line emissions are amplified by factors μ ∼ 6─13. We estimate extremely compact sizes—≲0.5 kpc for the star-forming region and ≲1 kpc for the gas component—with no clear evidence of rotation or ongoing merging events. We perform broadband SED fitting and retrieve the intrinsic demagnified physical properties of the source, which is found to feature a very high star formation rate, ≳103 M ⊙ yr−1, which, given the compact sizes, is on the verge of the Eddington limit for starbursts; the radio luminosity at 6 cm from the available EVLA observations is consistent with star formation activity. The galaxy is found to be extremely rich in gas ∼1011 M ⊙ and dust ≳109 M ⊙. The stellar content ≲1011 M ⊙ places the source well above the main sequence of star-forming galaxies, indicating that the starburst is rather young, with an estimated age ∼108 yr. Our results indicate that the overall properties of HATLASJ113526.2-01460 are consistently explained by in situ galaxy formation and evolution scenarios.

Keywords: Galaxy formation, Submillimeter astronomy, Strong gravitational lensing, High-redshift galaxies
Magnetospheric Multiscale Observations of Markov Turbulence on Kinetic Scales. In our previous studies we have examined solar wind and magnetospheric plasma turbulence, including Markovian character on large inertial magnetohydrodynamic scales. Here we present the results of the statistical analysis of magnetic field fluctuations in the Earth's magnetosheath, based on the Magnetospheric Multiscale mission at much smaller kinetic scales. Following our results on spectral analysis with very large slopes of about -16/3, we apply a Markov-process approach to turbulence in this kinetic regime. It is shown that the Chapman-Kolmogorov equation is satisfied and that the lowest-order Kramers-Moyal coefficients describing drift and diffusion with a power-law dependence are consistent with a generalized Ornstein-Uhlenbeck process. The solutions of the Fokker-Planck equation agree with experimental probability density functions, which exhibit a universal global scale invariance through the kinetic domain. In particular, for moderate scales we have the kappa distribution described by various peaked shapes with heavy tails, which, with large values of the kappa parameter, are reduced to the Gaussian distribution for large inertial scales. This shows that the turbulence cascade can be described by the Markov processes also on very small scales. The obtained results on kinetic scales may be useful for a better understanding of the physical mechanisms governing turbulence.

Keywords: Space plasmas, Magnetohydrodynamics, Heliosphere, Interplanetary turbulence, Solar wind, Interplanetary physics
COSMOS2020: Identification of High-z Protocluster Candidates in COSMOS. We conduct a systematic search for protocluster candidates at z ≥ 6 in the Cosmic Evolution Survey (COSMOS) field using the recently released COSMOS2020 source catalog. We select galaxies using a number of selection criteria to obtain a sample of galaxies that have a high probability of being inside a given redshift bin. We then apply overdensity analysis to the bins using two density estimators, a Weighted Adaptive Kernel estimator and a Weighted Voronoi Tessellation estimator. We have found 15 significant (&gt;4σ) candidate galaxy overdensities across the redshift range 6 ≤ z ≤ 7.7. The majority of the galaxies appear to be on the galaxy main sequence at their respective epochs. We use multiple stellar-mass-to-halo-mass conversion methods to obtain a range of dark matter halo mass estimates for the overdensities in the range of ~1011-1013 M ⊙, at the respective redshifts of the overdensities. The number and the masses of the halos associated with our protocluster candidates are consistent with what is expected from the area of a COSMOS-like survey in a standard Λ cold dark matter cosmology. Through comparison with simulation, we expect that all of the overdensities at z ≃ 6 will evolve into Virgo-/Coma-like clusters at present (i.e., with masses ~1014-1015 M ⊙). Compared to other overdensities identified at z ≥ 6 via narrowband selection techniques, the overdensities presented appear to have ~10× higher stellar masses and star formation rates (SFRs). We compare the evolution in the total SFR and stellar mass content of the protocluster candidates across the redshift range 6 ≤ z ≤ 7.7 and find agreement with the total average SFR from simulations.

Keywords: Large-scale structure of the universe, Galaxy evolution, High-redshift galaxy clusters
Nightside Ionospheric Structure and Composition on Mars Driven by Energetic Electron Precipitation. Ionospheric chemistry plays an unexpectedly important role in the evolution of planetary habitability. This study is dedicated to a detailed modeling of the nightside Martian ionospheric structure and composition, a topic that has been poorly explored due to the absence of relevant measurements, but now becomes tractable owing to the unprecedented measurements made by the Mars Atmosphere and Volatile Evolution. Two-stream kinetic calculations and time-dependent fluid calculations are coupled to derive the nightside density profiles at 100-300 km for a large number of ion species, assuming solar wind electron precipitation as the only viable ionizing source in the ideal nonmagnetized atmosphere. Our calculations indicate the presence of a well-defined ionospheric peak at 146 km with a peak density of 8500 cm-3, as driven by the strong atmospheric "absorption" of precipitating electrons at low altitudes. The distribution of nonterminal species is roughly under chemical equilibrium below 170 km, whereas for terminal species such as NO+ and HCO+, diffusion is effective at essentially all altitudes, in direct contrast to the dayside behavior. In the more realistic magnetized atmosphere, the ionospheric peak seldom exists due to the patchiness of electron precipitation. In particular, our model results agree fairly well with the MAVEN measurements, especially in view of the coincidence between electron depletion and thermal plasma void seen along many MAVEN orbits. Compared to the dayside, the nightside ionospheric composition has a much higher proportion of NO+ and lower proportion of CO2 +, likely indicative of nightside enhancement of atmospheric O and N.

Keywords: Mars, Planetary ionospheres, Planetary atmospheres
Solar Coronal Heating Fueled by Random Bursts of Fine-scale Magnetic Reconnection in Turbulent Plasma Regions. Coronal heating is a longstanding issue in solar physics as well as plasma physics in general. In recent years, significant resolution improvements of satellite observations have contributed to a deeper understanding of small-scale physics, e.g., magnetic reconnection processes on fine scales inside the turbulent geo-magnetosheath. Coronal plasmas feature turbulent complexity of flows and magnetic fields with similar fine scales, and thus electron magnetic reconnection is very likely to be excited in the coronal region working as one of the ways to heat the solar corona, which offers a possible new mechanism for the nanoflare model proposed by Parker. We in this paper simulate and analyze the magnetic reconnection processes on a fine scale of the electron skin depth, with a particle-in-cell treatment, and estimate its contribution to coronal heating. The result shows that the electron magnetic reconnection can provide substantial heating efficiency for heating the corona to its observed temperature, once the reconnection events are reasonably spread.

Keywords: Solar coronal heating, Solar magnetic reconnection
Plasmoids, Flows, and Jets during Magnetic Reconnection in a Failed Solar Eruption. We report a detailed analysis of a failed eruption and flare in active region 12018 on 2014 April 3 using multiwavelength observations from the Solar Dynamics Observatory/Atmospheric Imaging Assembly, IRIS, STEREO, and Hinode/Solar Optical Telescope. At least four jets were observed to emanate from the cusp of this small active region (large bright point) with a null-point topology during the 2 hr prior to the slow rise of a filament. During the filament slow rise multiple plasma blobs were seen, most likely formed in a null-point current sheet near the cusp. The subsequent filament eruption, which was outside the IRIS field of view, was accompanied by a flare but remained confined. During the explosive flare reconnection phase, additional blobs appeared repetitively and moved bidirectionally within the flaring region below the erupting filament. The filament kinked, rotated, and underwent leg-leg reconnection as it rose, yet it failed to produce a coronal mass ejection. Tiny jet-like features in the fan loops were detected during the filament slow rise/preflare phase. We interpret them as signatures of reconnection between the ambient magnetic field and the plasmoids leaving the null-point sheet and streaming along the fan loops. We contrast our interpretation of these tiny jets, which occur within the large-scale context of a failed filament eruption, with the local nanoflare-heating scenario proposed by Antolin et al.

Keywords: Plasma jets, Solar flares, Solar magnetic reconnection, Solar filament eruptions
Radio and γ-Ray Variability in Blazar S5 0716+714: A Year-like Quasi-periodic Oscillation in the Radio Light Curve. The nearly 33 yr long-term radio light curve obtained with the Metsähovi Radio Observatory 14 m telescope at 37 GHz and the recent 12.7 yr γ-ray light curve of the blazar S5 0716+714 at 0.1-300 GeV from the Fermi Large Area Telescope (Fermi-LAT) were analyzed by using the Lomb-Scargle periodogram and the weighted wavelet Z-transform techniques. In the radio light curve, we discovered a possible quasi-periodic oscillation (QPO) signal of about 352 ± 23 days at a confidence level of ~3σ. We recalculated the periodicity and its significance in a chosen time range that has higher variability and denser sampling, and then found that the significance had increased to a confidence level of 99.996% (~4.1σ). This QPO component was further confirmed by fitting a linear autoregressive integrated moving average model to the selected radio light curve. A possible QPO of 960 ± 80 days at a 99.35% level (~2.7σ) was found in the γ-ray light curve, which generally agrees with the earlier QPO claims of S5 0716+714. This paper discusses possible mechanisms for this potential year-like QPO. One possibility is a pure geometrical scenario with blobs moving helically inside the jet. Another is a supermassive binary black hole involving a gravitational wave-driven regime. In the latter scenario, we derived a milliparsec separation in the binary system that undergoes coalescence within a century due to the emission of low-frequency gravitational waves.

Keywords: Blazars, Relativistic jets, Active galactic nuclei, Time series analysis
The Observable Properties of Galaxy Accretion Events in Milky Way-like Galaxies in the FIRE-2 Cosmological Simulations. In the Λ-Cold Dark Matter model of the universe, galaxies form in part through accreting satellite systems. Previous works have built an understanding of the signatures of these processes contained within galactic stellar halos. This work revisits that picture using seven Milky Way-like galaxies in the Latte suite of FIRE-2 cosmological simulations. The resolution of these simulations allows a comparison of contributions from satellites aboveM * ≳ 10 × 7 M ⊙, enabling the analysis of observable properties for disrupted satellites in a fully self-consistent and cosmological context. Our results show that the time of accretion and the stellar mass of an accreted satellite are fundamental parameters that in partnership dictate the resulting spatial distribution, orbital energy, and [α/Fe]-[Fe/H] compositions of the stellar debris of such mergers at present day. These parameters also govern the resulting dynamical state of an accreted galaxy at z = 0, leading to the expectation that the inner regions of the stellar halo (R GC ≲ 30 kpc) should contain fully phase-mixed debris from both lower- and higher-mass satellites. In addition, we find that a significant fraction of the lower-mass satellites accreted at early times deposit debris in the outer halo (R GC &gt; 50 kpc) that are not fully phased-mixed, indicating that they could be identified in kinematic surveys. Our results suggest that, as future surveys become increasingly able to map the outer halo of our Galaxy, they may reveal the remnants of long-dead dwarf galaxies whose counterparts are too faint to be seen in situ in higher-redshift surveys.

Keywords: Galaxy formation, Milky Way stellar halo, Milky Way dynamics, Milky Way Galaxy
Environments of Type Ia Supernovae with Different Relative Equivalent Widths of the Si II Feature in Their Spectra. Although type Ia supernovae (SNe Ia) are very important in many astrophysical fields, such as cosmology, their explosion mechanisms and progenitor systems still remain unclear. In physics, the relative equivalent width (REW) of the Si II 635.5 nm absorption feature reflects the velocity interval of the silicon in the SN ejecta, which may then provide constraints on the explosion mechanisms of SNe Ia. In this paper, we divide the SNe Ia into broad-line (BL) and normal-line (NL) subsamples, based on the REW of the Si II 635.5 nm absorption lines around their maximum lights, and we find that the BL SNe Ia have a dimmer mean brightness than the NL ones, which is possibly a result of their different metallicities. However, based on a pixel statistics study of the environments of the two subsamples, we do not find any significant potential differences in the environments of the BL and NL SNe Ia, which implies that the explosion mechanisms of SNe Ia could be independent of their progenitor populations.

Keywords: Supernova remnants, White dwarf stars, Type Ia supernovae
Strongest Coronal Magnetic Fields in Solar Cycles 23 and 24: Probing, Statistics, and Implications. A strong coronal magnetic field, when present, manifests itself as bright microwave sources at high frequencies produced by the gyroresonant (GR) emission mechanism in thermal coronal plasma. The highest frequency at which this emission is observed is proportional to the absolute value of the strongest coronal magnetic field on the line of sight. Although no coronal magnetic field larger than roughly 2000 G has been expected, recently a field at least 2 times larger has been reported. Here, we report on a search for and a statistical study of such strong coronal magnetic fields using high-frequency GR emission. A historic record of spatially resolved microwave observations at high frequencies, 17 and 34 GHz, is available from the Nobeyama RadioHeliograph for a period covering more than 20 yr (1995-2018). Here, we employ this data set to identify sources of bright GR emission at 34 GHz and perform a statistical analysis of the identified GR cases to quantify the strongest coronal magnetic fields during two solar cycles. We found that although active regions with a strong magnetic field are relatively rare (less than 1% of all active regions), they appear regularly on the Sun. These active regions are associated with prominent manifestations of solar activity.

Keywords: Solar active region magnetic fields, Sunspots, Active sun, Astronomy data analysis, Solar radio emission, Active solar corona