Sazuna/UAT_keywords huggingface dataset:
The Baltimore Oriole's Nest: Cool Winds from the Inner and Outer Parts of a Star-forming Galaxy at z = 1.3. Strong galactic winds are ubiquitous at z ≳ 1. However, it is not well-known where inside galaxies these winds are launched from. We study the cool winds (~104 K) in two spatial regions of a massive galaxy at z = 1.3, which we nickname the "Baltimore Oriole's Nest." The galaxy has a stellar mass of 1010.3±0.3 M ⊙, is located on the star-forming main sequence, and has a morphology indicative of a recent merger. Gas kinematics indicate a dynamically complex system with velocity gradients ranging from 0 to 60 km s-1. The two regions studied are: a dust-reddened center (Central region), and a blue arc at 7 kpc from the center (Arc region). We measure the Fe II and Mg II absorption line profiles from deep Keck/DEIMOS spectra. Blueshifted wings up to 450 km s-1 are found for both regions. The Fe II column densities of winds are 1014.7±0.2 cm-2 and 1014.6±0.2 cm-2 toward the Central and Arc regions, respectively. Our measurements suggest that the winds are most likely launched from both regions. The winds may be driven by the spatially extended star formation, the surface density of which is around 0.2 M ⊙ yr-1 · kpc-2 in both regions. The mass outflow rates are estimated to be 4 M ⊙ yr-1 and 3 M ⊙ yr-1 for the Central and Arc regions, with uncertainties of one order of magnitude or more. The findings of this work and a few previous studies suggest that the cool galactic winds at z ≳ 1 might be commonly launched from the entire spatial extents of their host galaxies, due to extended galaxy star formation.

Keywords: Galactic winds, Galaxy formation, Stellar feedback
Detailed Thermal and Nonthermal Processes in an A-class Microflare. How microflares behave and differ from large flares is an important question in flare studies. Although they have been extensively investigated, microflares are not fully understood in terms of their detailed energy release processes and the role of energetic electrons. A recent study on an A-class microflare suggests the existence of a nonthermal component down to 6.5 keV, indicating that accelerated electrons play an important role in microflares, as in large flares. Here, we revisit this event, and present a comprehensive, quantitative analysis of the energy release and plasma heating processes. Using careful differential emission measure (DEM) analysis, we calculate the thermal X-ray fluxes. By subtracting this multithermal component from the observed data, we confirm the existence of the remaining nonthermal component. In addition, we analyze the clear evaporation process and report the first imaging evidence for a low-energy cutoff of energetic electrons in EM maps of &gt;10 MK plasma, which first appeared as two coronal sources significantly above the chromospheric footpoints. Detailed calculations of electron transport, based on the electron parameters and the evolution of loop dynamics, provide strong evidence of a beam-driven plasma heating process with a low-energy cutoff consistent with that derived independently from DEM analysis. This study reveals the important role of electron thermalization and low-energy cutoffs in the physical processes of microflares.

Keywords: Solar atmosphere, Solar flares, The Sun, Solar x-ray emission, Non-thermal radiation sources, Solar corona, Solar x-ray flares, Solar chromospheric heating, Solar particle emission, Solar chromosphere
The Eel Pulsar Wind Nebula: A PeVatron-candidate Origin for HAWC J1826-128 and HESS J1826-130. HAWC J1826-128 is one of the brightest Galactic TeV γ-ray sources detected by the High Altitude Water Cherenkov (HAWC) observatory, with photon energies extending up to nearly ~100 TeV. This HAWC source spatially coincides with the H.E.S.S. TeV source HESS J1826-130 and the "Eel" pulsar wind nebula (PWN), which is associated with the GeV pulsar PSR J1826-1256. In the X-ray band, Chandra and XMM-Newton revealed that the Eel PWN is composed of both a compact nebula (~15″) and diffuse X-ray emission (~6' × 2') extending away from the pulsar. Our NuSTAR observation detected hard X-ray emission from the compact PWN up to ~20 keV and evidence of the synchrotron burn-off effect. In addition to the spatial coincidence between HESS J1826-130 and the diffuse X-ray PWN, our multiwavelength spectral energy distribution (SED) analysis using X-ray and γ-ray data establishes a leptonic origin of the TeV emission associated with the Eel PWN. Furthermore, our evolutionary PWN SED model suggests (1) a low PWN B-field of ~1 μG, (2) a significantly younger pulsar age (t ~ 5.7 kyr) than the characteristic age (τ = 14.4 kyr), and (3) a maximum electron energy of ${E}_{\max }=2$ PeV. The low B-field, as well as the putative supersonic motion of the pulsar, may account for the asymmetric morphology of the diffuse X-ray emission. Our results suggest that the Eel PWN may be a leptonic PeVatron particle accelerator powered by the ~6 kyr old pulsar PSR J1826-1256 with a spin-down power of 3.6 × 1036 erg s-1.

Keywords: X-ray astronomy, Gamma-ray observatories, High energy astrophysics, Rotation powered pulsars, X-ray telescopes, Gamma-ray telescopes, Pulsars, Gamma-ray astronomy
Studying Interstellar Turbulence Driving Scales Using the Bispectrum. We demonstrate the utility of the bispectrum, the Fourier three-point correlation function, for studying driving scales of magnetohydrodynamic (MHD) turbulence in the interstellar medium. We calculate the bispectrum by implementing a parallelized Monte Carlo direct measurement method, which we have made publicly available. In previous works, the bispectrum has been used to identify nonlinear scaling correlations and break degeneracies in lower-order statistics like the power spectrum. We find that the bicoherence, a related statistic which measures phase coupling of Fourier modes, identifies turbulence-driving scales using density and column density fields. In particular, it shows that the driving scale is phase-coupled to scales present in the turbulent cascade. We also find that the presence of an ordered magnetic field at large scales enhances phase coupling as compared to a pure hydrodynamic case. We therefore suggest the bispectrum and bicoherence as tools for searching for non-locality for wave interactions in MHD turbulence.

Keywords: Magnetohydrodynamics, Interplanetary turbulence, Astrostatistics techniques, Plasma astrophysics, Astrostatistics, Interstellar plasma, Interstellar medium, Astrophysical fluid dynamics
Survival of the Fittest: Numerical Modeling of SN 2014C. Initially classified as a Type Ib supernova (SN), ~100 days after the explosion SN 2014C made a transition to a Type II SN, presenting a gradual increase in the Hα emission. This has been interpreted as evidence of interaction between the SN shock wave and a massive shell previously ejected from the progenitor star. In this paper we present numerical simulations of the propagation of the SN shock through the progenitor star and its wind, as well as the interaction of the SN ejecta with the massive shell. To determine with high precision the structure and location of the shell, we couple a genetic algorithm to a hydrodynamic and a bremsstrahlung radiation transfer code. We iteratively modify the density stratification and location of the shell by minimizing the variance between X-ray observations and synthetic predictions computed from the numerical model, allowing the shell structure to be completely arbitrary. By assuming spherical symmetry, we found that our best-fit model has a shell mass of 2.6 M ⊙; extends from 1.6 × 1016 cm to 1.87 × 1017 cm, implying that it was ejected ~ 60/(v  w /100 km s-1) yr before the SN explosion; and has a density stratification with an average behavior ~r -3 but presenting density fluctuations larger than one order of magnitude. Finally, we predict that if the density stratification follows the same power-law behavior, the SN will break out from the shell by mid-2022, i.e., 8.5 yr after explosion.

Keywords: Stellar physics, Supernova dynamics, High energy astrophysics
A Possible Gamma-Ray Enhancement Event in Tycho's Supernova Remnant. We report a possible γ-ray enhancement event detected from Tycho's supernova remnant (SNR), the outcome of a type Ia supernova explosion that occurred in the year 1572. The event lasted for 1.5 yr and showed a factor of 3.6 flux increase mainly in the energy range of 4-100 GeV, while notably accompanied with two 478 GeV photons. Several young SNRs (including Tycho's SNR) were previously found to show peculiar X-ray structures with flux variations in one- or several-year timescales, such an event at γ-ray energies is for the first time seen. The year-long timescale of the event suggests a synchrotron radiation process, but the hard γ-ray emission requires extreme conditions of either ultrahigh energies for the electrons up to ~10 PeV (well above the cosmic-ray knee energy) or high inhomogeneity of the magnetic field in the SNR. This event in Tycho's SNR is likely analogous to the γ-ray flares observed in the Crab Nebula, the comparably short timescales of them both requiring a synchrotron process, and similar magnetohydrodynamic processes such as magnetic reconnection would be at work as well in the SNR to accelerate particles to ultrarelativistic energies. The event, if confirmed, helps reveal the more complicated side of the physical processes that can occur in young SNRs.

Keywords: Supernova remnants, Gamma-rays, High energy astrophysics
Longitudinally Asymmetric Stratospheric Oscillation on a Tidally Locked Exoplanet. Using a three-dimensional general circulation model, we show that the atmospheric dynamics on a tidally locked Earth-like exoplanet, simulated with the planetary and orbital parameters of Proxima Centauri b, support a longitudinally asymmetric stratospheric wind oscillation (LASO), analogous to Earth's quasi-biennial oscillation (QBO). In our simulations, the LASO has a vertical extent of 35-55 km, a period of 5-6.5 months, and a peak-to-peak wind speed amplitude of -70 to +130 m s-1 with a maximum at an altitude of 41 km. Unlike the QBO, the LASO displays longitudinal asymmetries related to the asymmetric thermal forcing of the planet and to interactions with the resulting stationary Rossby waves. The equatorial gravity wave sources driving the LASO are localized in the deep convection region at the substellar point and in a jet exit region near the western terminator, unlike the QBO, for which these sources are distributed uniformly around the planet. Longitudinally, the western terminator experiences the highest wind speeds and undergoes reversals earlier than other longitudes. The antistellar point only experiences a weak oscillation with a very brief, low-speed westward phase. The QBO on Earth is associated with fluctuations in the abundances of water vapor and trace gases such as ozone, which are also likely to occur on exoplanets if these gases are present. Strong fluctuations in temperature and the abundances of atmospheric species at the terminators will need to be considered when interpreting atmospheric observations of tidally locked exoplanets.

Keywords: Exoplanet dynamics, Extrasolar rocky planets, Exoplanets, Exoplanet atmospheric variability, Exoplanet atmospheres
The SAMI Galaxy Survey: The Internal Orbital Structure and Mass Distribution of Passive Galaxies from Triaxial Orbit-superposition Schwarzschild Models. Dynamical models are crucial for uncovering the internal dynamics of galaxies; however, most of the results to date assume axisymmetry, which is not representative of a significant fraction of massive galaxies. Here, we build triaxial Schwarzschild orbit-superposition models of galaxies taken from the SAMI Galaxy Survey, in order to reconstruct their inner orbital structure and mass distribution. The sample consists of 161 passive galaxies with total stellar masses in the range 109.5-1012 M ⊙. We find that the changes in internal structures within 1R e are correlated with the total stellar mass of the individual galaxies. The majority of the galaxies in the sample (73% ± 3%) are oblate, while 19% ± 3% are mildly triaxial and 8% ± 2% have triaxial/prolate shape. Galaxies with $\mathrm{log}{M}_{\star }/{M}_{\odot }\gt 10.50$ are more likely to be non-oblate. We find a mean dark matter fraction of f DM = 0.28 ± 0.20, within 1R e. Galaxies with higher intrinsic ellipticity (flatter) are found to have more negative velocity anisotropy β  r  (tangential anisotropy). β  r  also shows an anticorrelation with the edge-on spin parameter ${\lambda }_{\mathrm{Re},\mathrm{EO}}$ , so that β  r  decreases with increasing ${\lambda }_{\mathrm{Re},\mathrm{EO}}$ , reflecting the contribution from disk-like orbits in flat, fast-rotating galaxies. We see evidence of an increasing fraction of hot orbits with increasing stellar mass, while warm and cold orbits show a decreasing trend. We also find that galaxies with different (V/σ - h 3) kinematic signatures have distinct combinations of orbits. These results are in agreement with a formation scenario in which slow- and fast-rotating galaxies form through two main channels.

Keywords: Galaxy structure, Galaxy dynamics, Galaxy kinematics, Galaxy evolution
Multi-instrument Comparative Study of Temperature, Number Density, and Emission Measure during the Precursor Phase of a Solar Flare. We present a multi-instrument study of the two precursor brightenings prior to the M6.5 flare (SOL2015-06-22T18:23) in the NOAA Active Region 12371, with a focus on the temperature (T), electron number density (n), and emission measure (EM). The data used in this study were obtained from four instruments with a variety of wavelengths, i.e., the Solar Dynamics Observatory's Atmospheric Imaging Assembly (AIA), in six extreme ultraviolet (EUV) passbands; the Expanded Owens Valley Solar Array (EOVSA) in microwave (MW); the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in hard X-rays (HXR); and the Geostationary Operational Environmental Satellite (GOES) in soft X-rays (SXR). We compare the temporal variations of T, n, and EM derived from the different data sets. Here are the key results. (1) GOES SXR and AIA EUV have almost identical EM variations (1.5-3 × 1048 cm-3) and very similar T variations, from 8 to 15 million Kelvin (MK). (2) Listed from highest to lowest, EOVSA MW provides the highest temperature variations (15-60 MK), followed by RHESSI HXR (10-24 MK), then GOES SXR and AIA EUV (8-15 MK). (3) The EM variation from the RHESSI HXR measurements is always less than the values from AIA EUV and GOES SXR by at most 20 times. The number density variation from EOVSA MW is greater than the value from AIA EUV by at most 100 times. The results quantitatively describe the differences in the thermal parameters at the precursor phase, as measured by different instruments operating at different wavelength regimes and for different emission mechanisms.

Keywords: Solar flares, The Sun, Solar physics, Solar x-ray flares, Solar radio flares, Solar particle emission
Electron Acceleration by Moderate-Mach-number Low-β Shocks: Particle-in-Cell Simulations. Particle acceleration is ubiquitous at shock waves, occurring on scales ranging from supernova remnants in the universe to coronal-mass-ejection-driven shocks and planetary bow shocks in the heliosphere. The most promising mechanism responsible for the almost universally observed power-law spectra is diffusive shock acceleration (DSA). However, how electrons are preaccelerated by different shocks to the energy required by the DSA theory is still unclear. In this paper, we perform two-dimensional particle-in-cell plasma simulations to investigate how the magnetic field orientations, with respect to simulation planes, affect electron preacceleration in moderate-Mach-number low- β shocks. Simulation results show that instabilities can be different as the simulation planes capture different trajectories of particles. For magnetic fields perpendicular to the simulation plane, electron cyclotron drift instability dominates in the foot. Electrons can be trapped by the electrostatic wave and undergo shock-surfing acceleration. For magnetic fields lying in the simulation plane, whistler waves produced by modified two-stream instability dominate in the foot and scatter the electrons. In both cases, electrons undergo multistage acceleration in the foot, shock surface, and immediate downstream, during which process shock-surfing acceleration takes place as part of the preacceleration mechanism in moderate-Mach-number quasi-perpendicular shocks.

Keywords: Shocks, Plasma astrophysics
A Spectroscopic View of the JWST/GTO Strong Lensing Cluster A1489. We discuss a spectroscopic survey of the strong lensing cluster A1489 that includes redshifts for 195 cluster members along with central velocity dispersions for 188 cluster members. The caustic technique applied to the redshift survey gives the dynamical parameters M 200 = (1.25 ± 0.09) × 1015 M ⊙, R 200 = 1.97 ± 0.05 Mpc, and a cluster line-of-sight velocity dispersion of 1150 ± 72 km s-1 within R 200. These parameters are very similar to those of other strong lensing systems with comparably large Einstein radii. We use the spectroscopy and deep photometry to demonstrate that A1489 is probably dynamically active; its four brightest cluster galaxies have remarkably different rest-frame radial velocities. Like other massive strong lensing clusters, the velocity dispersion function for members of A1489 shows an excess for dispersions ≳250 km s-1. The central dispersions also provide enhanced constraints on future lensing models.

Keywords: Galaxy clusters, Redshift surveys
Characterizing the γ-Ray Variability of Active Galactic Nuclei with the Stochastic Process Method. Gamma-ray astronomy in the time domain has been by now progressed further as the variabilities of active galactic nuclei (AGNs) on different timescales have been reported a lot. We study the γ-ray variabilities of 23 jetted AGNs by applying a stochastic process method to the ~12.7 yr long-term light curve (LC) obtained by the Fermi-Large Area Telescope (Fermi-LAT). In this method, the stochastically driven damped simple harmonic oscillator (SHO) and the damped random-walk (DRW) models are used to model the long-term LCs. Our results show that the long-term variabilities of 23 AGNs can be characterized well by both SHO and DRW models. However, the SHO model is restricted in the overdamped mode, and the parameters are poorly constrained. The SHO power spectral densities (PSDs) are the same as those of the typical DRW PSD. In the plot of the rest-frame timescale that corresponds to the broken frequency in the PSD versus black hole mass, the intrinsic, characteristic γ-ray timescales of 23 AGNs occupy almost the same space with the optical variability timescales obtained from the accretion disk emission. This suggests a connection between the jet and the accretion disk. As with the optical variability of the AGN accretion disk, the γ-ray timescale is also consistent with the thermal timescale caused by the thermal instability in the standard accretion disk of AGNs.

Keywords: Jets, Light curves, Active galactic nuclei, Gamma-rays, Time series analysis
Mixing the Solar Wind Proton and Electron Scales. Theory and 2D-PIC Simulations of Firehose Instability. Firehose-like instabilities (FIs) are cited in multiple astrophysical applications. Of particular interest are the kinetic manifestations in weakly collisional or even collisionless plasmas, where these instabilities are expected to contribute to the evolution of macroscopic parameters. Relatively recent studies have initiated a realistic description of FIs, as induced by the interplay of both species, electrons and protons, dominant in the solar wind plasma. This work complements the current knowledge with new insights from linear theory and the first disclosures from 2D-PIC simulations, identifying the fastest growing modes near the instability thresholds and their long-run consequences on the anisotropic distributions. Thus, unlike previous setups, these conditions are favorable to those aperiodic branches that propagate obliquely to the uniform magnetic field, with (maximum) growth rates higher than periodic, quasi-parallel modes. Theoretical predictions are, in general, confirmed by the simulations. The aperiodic electron FI (a-EFI) remains unaffected by the proton anisotropy, and saturates rapidly at low-level fluctuations. Regarding the FI at proton scales, we see a stronger competition between the periodic and aperiodic branches. For the parameters chosen in our analysis, the aperiodic proton FI (a-PFI) is excited before than the periodic proton FI (p-PFI), with the latter reaching a significantly higher fluctuation power. However, both branches are significantly enhanced by the presence of anisotropic electrons. The interplay between EFIs and PFIs also produces a more pronounced proton isotropization.

Keywords: Space plasmas, Solar wind, Plasma astrophysics
Constraining Black Hole Natal Kicks with Astrometric Microlensing. Multiple pieces of evidence suggest that neutron stars receive large kicks when formed from the remnant of a collapsing star. However, the evidence for whether black holes (BHs) receive natal kicks is less clear, reliant on weak constraints from the analysis of BH X-ray binaries and massive runaway and walkaway stars. Here we show, for the first time, that recent microlensing detections offer a new method for measuring the kicks BHs receive at birth. When a BH is identified through both photometric and astrometric microlensing and when the lensed star has a known distance and proper motion, the mass, distance, and proper motion of the BH can be determined. We study the runaway velocities for components of eccentric binaries disrupted during a supernova (SN), finding the peculiar velocity correlates strongly with the kick a BH received at birth, typically within 20%, even when the natal kick is smaller than the orbital velocity. Therefore, by measuring the peculiar velocity of a BH or other compact object that formed from a binary which disrupted during core collapse, we are in effect measuring the natal kick that object received. We focus on MOA-2011-BLG-191/OGLE-2011-BLG-0462, an isolated, single BH detected by microlensing, and consider a range of possible formation scenarios, including its formation from the disruption of a binary during a SN event. We determine that MOA-2011-BLG-191/OGLE-2011-BLG-0462 has a Milky Way orbit consistent with a thick-disk population, but if it was formed within the kinematic thin disk it received a natal kick ≲100 km s-1.

Keywords: Black hole physics, Binary stars
SDSS-IV MaNGA: Exploring the Local Scaling Relations for N/O. We present, for the first time, the relationship between local stellar mass surface density, Σ*, and N/O derived from SDSS-IV MaNGA data, using a sample of 792,765 high signal-to-noise ratio star-forming spaxels. Using a combination of phenomenological modeling and partial correlation analysis, we find that Σ* alone is insufficient to predict the N/O in MaNGA spaxels and that there is an additional dependence on the local star formation rate surface density, ΣSFR. This effect is a factor of 3 stronger than the dependence of 12+log(O/H) on ΣSFR. Surprisingly, we find that the local N/O scaling relations also depend on the total galaxy stellar mass at fixed Σ* and the galaxy size at fixed stellar mass. We find that more compact galaxies are more nitrogen rich, even when Σ* and ΣSFR are controlled for. We show that ~50% of the variance of N/O is explained by the total stellar mass and size. Thus, the evolution of nitrogen in galaxies is set by more than just local effects and does not simply track the buildup of oxygen in galaxies. The precise form of the N/O-O/H relation is therefore sensitive to the sample of galaxies from which it is derived. This result casts doubt on the universal applicability of nitrogen-based strong-line metallicity indicators derived in the local universe.

Keywords: Galaxy properties, Interstellar abundances, Chemical abundances, Scaling relations, Chemical enrichment, Galaxy abundances, Galaxy evolution