Sazuna/UAT_keywords huggingface dataset:
The Nuclear Region of NGC 1365: Star Formation, Negative Feedback, and Outflow Structure. High-resolution observations of ionized and molecular gas in the nuclear regions of galaxies are indispensable for delineating the interplay of star formation, gaseous inflows, stellar radiation, and feedback processes. Combining our new Atacama Large Millimeter/submillimeter Array band 3 mapping and archival Very Large Telescope/MUSE data, we present a spatially resolved analysis of molecular and ionized gas in the central 5.4 kpc region of NGC 1365. We find the star formation rate/efficiency (SFR/SFE) in the inner circumnuclear ring is about 0.4/1.1 dex higher than in the outer regions. At a linear resolution of 180 pc, we obtain a superlinear Kennicutt-Schmidt law, demonstrating a steeper slope (1.96 ± 0.14) than previous results presumably based on lower-resolution observations. Compared to the northeastern counterpart, the southwestern dust lane shows lower SFE, but denser molecular gas and larger virial parameters. This is consistent with an interpretation of negative feedback from an active galactic nucleus (AGN) and/or starburst, in the sense that the radiation/winds can heat and interact with the molecular gas even in relatively dense regions. After subtracting the circular motion component of the molecular gas and the stellar rotation, we detect two prominent noncircular motion components of molecular and ionized hydrogen gas, reaching a line-of-sight velocity of up to 100 km s-1. We conclude that the winds or shocked gas from the central AGN may expel the low-density molecular gas and diffuse ionized gas on the surface of the rotating disk.

Keywords: Starburst galaxies, Seyfert galaxies, Galaxy kinematics
Comprehensive Laboratory Measurements Resolving the LMM Dielectronic Recombination Satellite Lines in Ne-like Fe xvii Ions. We investigated experimentally and theoretically dielectronic recombination (DR) populating doubly excited configurations $3l3l^{\prime}$ (LMM) in Fe xvii, the strongest channel for soft X-ray line formation in this ubiquitous species. We used two different electron beam ion traps and two complementary measurement schemes for preparing the Fe xvii samples and evaluating their purity, observing negligible contamination effects. This allowed us to diagnose the electron density in both EBITs. We compared our experimental resonant energies and strengths with those of previous independent work at a storage ring as well as those of configuration interaction, multiconfiguration Dirac-Fock calculations, and many-body perturbation theory. This last approach showed outstanding predictive power in the comparison with the combined independent experimental results. From these we also inferred DR rate coefficients, unveiling discrepancies from those compiled in the OPEN-ADAS and AtomDB databases.

Keywords: Spectral line lists, Theoretical techniques, Atomic physics, Laboratory astrophysics, Experimental techniques, Dielectronic recombination, Atomic data benchmarking
The GADOT Galaxy Survey: Dense Gas and Feedback in Herschel-selected Starburst Galaxies at Redshifts 2 to 6. We report the detection of 23 OH+ 1 → 0 absorption, emission, or P-Cygni-shaped lines and CO(J = 9→8) emission lines in 18 Herschel-selected z = 2-6 starburst galaxies with the Atacama Large Millimeter/submillimeter Array and the NOrthern Extended Millimeter Array, taken as part of the Gas And Dust Over cosmic Time Galaxy Survey. We find that the CO(J = 9→8) luminosity is higher than expected based on the far-infrared luminosity when compared to nearby star-forming galaxies. Together with the strength of the OH+ emission components, this may suggest that shock excitation of warm, dense molecular gas is more prevalent in distant massive dusty starbursts than in nearby star-forming galaxies on average, perhaps due to an impact of galactic winds on the gas. OH+ absorption is found to be ubiquitous in massive high-redshift starbursts, and is detected toward 89% of the sample. The majority of the sample shows evidence for outflows or inflows based on the velocity shifts of the OH+ absorption/emission, with a comparable occurrence rate of both at the resolution of our observations. A small subsample appears to show outflow velocities in excess of their escape velocities. Thus, starburst-driven feedback appears to be important in the evolution of massive galaxies in their most active phases. We find a correlation between the OH+ absorption optical depth and the dust temperature, which may suggest that warmer starbursts are more compact and have higher cosmic-ray energy densities, leading to more efficient OH+ ion production. This is in agreement with a picture in which these high-redshift galaxies are "scaled-up" versions of the most intense nearby starbursts.

Keywords: Starburst galaxies, Interstellar line emission, Interstellar line absorption, Millimeter astronomy, Active galaxies, Infrared excess galaxies, Galaxy evolution, Submillimeter astronomy, High-redshift galaxies
Solar Wind Discontinuity Transformation at the Bow Shock. Solar wind plasma at the Earth's orbit carries transient magnetic field structures including discontinuities. Their interaction with the Earth's bow shock can significantly alter discontinuity configuration and stability. We investigate such an interaction for the most widespread type of solar wind discontinuities—rotational discontinuities (RDs). We use a set of in situ multispacecraft observations and perform kinetic hybrid simulations. We focus on the RD current density amplification that may lead to magnetic reconnection. We show that the amplification can be as high as two orders of magnitude and is mainly governed by three processes: the transverse magnetic field compression, global thinning of RD, and interaction of RD with low-frequency electromagnetic waves in the magnetosheath, downstream of the bow shock. The first factor is found to substantially exceed simple hydrodynamic predictions in most observed cases, the second effect has a rather moderate impact, while the third causes strong oscillations of the current density. We show that the presence of accelerated particles in the bow shock precursor highly boosts the current density amplification, making the postshock magnetic reconnection more probable. The pool of accelerated particles strongly affects the interaction of RDs with the Earth's bow shock, as it is demonstrated by observational data analysis and hybrid code simulations. Thus, shocks should be distinguished not by the inclination angle, but rather by the presence of foreshocks populated with shock reflected particles. Plasma processes in the RD-shock interaction affect magnetic structures and turbulence in the Earth's magnetosphere and may have implications for the processes in astrophysics.

Keywords: Interplanetary discontinuities, Planetary bow shocks
The Luminous and Double-peaked Type Ic Supernova 2019stc: Evidence for Multiple Energy Sources. We present optical photometry and spectroscopy of SN 2019stc (=ZTF19acbonaa), an unusual Type Ic supernova (SN Ic) at a redshift of z = 0.117. SN 2019stc exhibits a broad double-peaked light curve, with the first peak having an absolute magnitude of Mr = -20.0 mag, and the second peak, about 80 rest-frame days later, Mr = -19.2 mag. The total radiated energy is large, Erad ≈ 2.5 × 1050 erg. Despite its large luminosity, approaching those of Type I superluminous supernovae (SLSNe), SN 2019stc exhibits a typical SN Ic spectrum, bridging the gap between SLSNe and SNe Ic. The spectra indicate the presence of Fe-peak elements, but modeling of the first light-curve peak with radioactive heating alone leads to an unusually high nickel mass fraction of fNi ≈ 0.31 (MNi ≈ 3.2 M⊙). Instead, if we model the first peak with a combined magnetar spin-down and radioactive heating model we find a better match with Mej ≈ 4 M⊙, a magnetar spin period of Pspin ≈ 7.2 ms, and magnetic field of B ≈ 1014 G, and fNi ≲ 0.2 (consistent with SNe Ic). The prominent second peak cannot be naturally accommodated with radioactive heating or magnetar spin-down, but instead can be explained as circumstellar interaction with ≈0.7 M⊙ of hydrogen-free material located ≈400 au from the progenitor. Accounting for the ejecta mass, circumstellar shell mass, and remnant neutron star mass, we infer a CO core mass prior to explosion of ≈6.5 M⊙. The host galaxy has a metallicity of ≈0.26 Z⊙, low for SNe Ic but consistent with SLSNe. Overall, we find that SN 2019stc is a transition object between normal SNe Ic and SLSNe.

Keywords: Type Ic supernovae, Supernovae
ARTEMIS Observations of Plasma Waves in Laminar and Perturbed Interplanetary Shocks. The "Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun" mission provides a unique opportunity to study the structure of interplanetary shocks and the associated generation of plasma waves with frequencies between ∼50 and 8000 Hz due to its long duration electric and magnetic field burst waveform captures. We compare wave properties and occurrence rates at 11 quasi-perpendicular interplanetary shocks with burst data within 10 minutes (∼3200 proton gyroradii upstream, ∼1900 downstream) of the shock ramp. A perturbed shock is defined as possessing a large amplitude whistler precursor in the quasi-static magnetic field with an amplitude greater than 1/3 the difference between the upstream and downstream average magnetic field magnitudes; laminar shocks lack these large precursors and have a smooth, step function-like transition. In addition to wave modes previously observed, including ion acoustic, whistler, and electrostatic solitary waves, waves in the ion acoustic frequency range that show rapid temporal frequency change are common. Three shocks had burst captures in the ramp; of these, the two laminar shocks contained a wide range of large amplitude wave modes in the ramp whereas the one perturbed shock contained no such waves. Thus, energy dissipation through wave-particle interactions is more prominent in these two laminar shocks than in the perturbed shock. Based on observations from all 11 shocks, the wave occurrence rates for laminar shocks are higher in the transition region, especially the ramp, than downstream. In contrast, perturbed shocks have approximately 2-3 times the wave occurrence rate downstream than laminar shocks.

Keywords: Space plasmas, Interplanetary shocks, Plasma physics, Interplanetary turbulence, Interplanetary discontinuities, Solar wind, Interplanetary magnetic fields
Model Light Curves for Type Ib and Ic Supernovae. Using the Monte Carlo code SEDONA, multiband photometry and spectra are calculated for supernovae derived from stripped helium stars with presupernova masses of 2.2 to 10.0 M⊙. The models are representative of evolution in close binaries and have previously been exploded using a parameterized one-dimensional model for neutrino transport. A subset, those with presupernova masses in the range of 2.2-5.6 M⊙, have many properties in common with observed Type Ib and Ic supernovae, including a median ejected mass near 2 M⊙, explosion energies near 1 × 1051 erg, typical 56Ni masses of 0.07-0.09 M⊙, peak times of about 20 days, and a narrow range for the V - R color index 10 days post-V-maximum near 0.3 mag. The median peak bolometric luminosity, near 1042.3 erg s-1, is fainter, however, than several observational tabulations, and the brightest explosion has a bolometric luminosity of only 1042.50 erg s-1. The brightest absolute B, V, and R magnitudes at peak are -17.2, -17.8, and -18.0. These limits are fainter than some allegedly typical Type Ib and Ic supernovae and could reflect problems in our models or in the observational analysis. Helium stars with lower and higher masses also produce interesting transients that may have been observed, including fast, faint, blue transients and long, red, faint Type Ic supernovae. New models are specifically presented for SN 2007Y, SN 2007gr, SN 2009jf, LSQ 13abf, SN 2008D, and SN 2010X.

Keywords: Type Ic supernovae, Core-collapse supernovae, Close binary stars, Type Ib supernovae, Light curves, Spectroscopy
The Changing-look Blazar B2 1420+32. Blazars are active galactic nuclei with their relativistic jets pointing toward the observer, comprising two major subclasses, flat-spectrum radio quasars (FSRQs) and BL Lac objects. We present multiwavelength photometric and spectroscopic monitoring observations of the blazar B2 1420+32, focusing on its outbursts in 2018-2020. Multiepoch spectra show that the blazar exhibited large-scale spectral variability in both its continuum and line emission, accompanied by dramatic gamma-ray and optical variability by factors of up to 40 and 15, respectively, on week to month timescales. Over the last decade, the gamma-ray and optical fluxes increased by factors of 1500 and 100, respectively. B2 1420+32 was an FSRQ with broad emission lines in 1995. Following a series of flares starting in 2018, it transitioned between BL Lac and FSRQ states multiple times, with the emergence of a strong Fe pseudocontinuum. Two spectra also contain components that can be modeled as single-temperature blackbodies of 12,000 and 5200 K. Such a collection of "changing-look" features has never been observed previously in a blazar. We measure gamma-ray-optical and interband optical lags implying emission-region separations of less than 800 and 130 gravitational radii, respectively. Since most emission-line flux variations, except the Fe continuum, are within a factor of 2-3, the transitions between FSRQ and BL Lac classifications are mainly caused by the continuum variability. The large Fe continuum flux increase suggests the occurrence of dust sublimation releasing more Fe ions in the central engine and an energy transfer from the relativistic jet to subrelativistic emission components.

Keywords: Black hole physics, Quasars, Blazars, Radio loud quasars, Active galactic nuclei, Time domain astronomy
The Decay of α-configuration Sunspots. To better understand the decay of different types of sunspots, we studied the decay of eight α-configuration sunspots by using the data that were acquired by the Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory. We followed their decay for about four days and analyzed the evolution of their photospheric area and magnetic field parameters. We found that the area and total magnetic flux of α sunspots show a near-linear decrease during their decay. Meanwhile, the area decay rate of an individual sunspot is not constant. The area decay of a sunspot can be divided into two stages, a slow and a rapid decay process. Moreover, according to the difference of the area decay of the penumbra and umbra, the α sunspots decay can be classified in three ways: the penumbra and umbra decay synchronously, the penumbra decays first, and the umbra decays first. In addition, the flux decay of the penumbra is lagging behind the decay of the penumbral area. This finding suggests that the vertical magnetic field of the sunspot penumbra increases significantly in the early stage of sunspot decay.

Keywords: Solar photosphere, Sunspots, Solar magnetic fields
Conditions for Justifying Single-fluid Approximation for Charged and Neutral Dust Fluids and a Smoothed Particle Magnetohydrodynamics Method for Dust-Gas Mixture. We describe a numerical scheme for magnetohydrodynamics simulations of dust-gas mixture by extending smoothed particle magnetohydrodynamics. We employ the single-species particle approach to describe dust-gas mixture with several modifications from the previous studies. We assume that the charged and neutral dust can be treated as single-fluid, that the electromagnetic force acts on the gas, and that that acting on the charged dust is negligible. The validity of these assumptions in the context of protostar formation is not obvious and is extensively evaluated. By investigating the electromagnetic force and electric current with terminal velocity approximation, it is found that as the dust size increases, the contribution of dust to them becomes smaller and negligible. We conclude that our assumption that the electromagnetic force on the dusts is negligible is valid for the dust size with ad ≳ 10 μm. On the other hand, they do not produce the numerical artifact for the dust ad ≲ 10 μm in the envelope and disk, where the perfect coupling between gas and dust is realized. However, we also found that our assumptions may break down in outflow (or under an environment with very strong magnetic field and low density) for the dust ad ≲ 10 μm. We conclude that our assumptions are valid in almost all cases where macroscopic dust dynamics is important in the context of protostar formation. We conduct numerical tests of dusty waves, dusty magnetohydrodynamics shocks, and gravitational collapse of magnetized cloud cores with our simulation code. The results show that our numerical scheme well reproduces the dust dynamics in the magnetized medium.

Keywords: Astrophysical dust processes, Star formation, Magnetohydrodynamical simulations
870 μm Dust Continuum of the Youngest Protostars in Ophiuchus. We present a 0.15 arcsec resolution (21 au) ALMA 870 μm continuum survey of 25 pointings containing 31 young stellar objects in the Ophiuchus molecular clouds. Using the dust continuum as a proxy for dust mass and circumstellar disk radius in our sample, we report mean masses of ${2.8}_{-1.3}^{+2.1}$ and ${2.5}_{-1.1}^{+9.2}$ M⊕ and mean radii of ${23.5}_{-1.2}^{+1.8}$ and ${16.5}_{-0.9}^{+2.8}$ au, for Class I and Flat spectrum protostars, respectively. In addition, we calculate the multiplicity statistics of the dust surrounding young stellar objects in Ophiuchus. The multiplicity fraction and companion star fraction of the combined Class I and Flats based solely on this work are 0.25 ± 0.09 and 0.33 ± 0.10, respectively, which are consistent with the values for Perseus and Orion. While we see clear differences in mass and radius between the Ophiuchus and Perseus/Orion protostellar surveys, we do not see any significant differences in the multiplicities of the various regions. We posit that there are some differences in the conditions for star formation in Ophiuchus that strongly affect disk size (and consequently disk mass), but does not affect system multiplicity, which could imply important variation in planet formation processes.

Keywords: Pre-main sequence stars, Young stellar objects, Radio interferometry, Protoplanetary disks
New Insight into the Rapid Burster by Insight-HXMT. We report the timing and spectral analyses of the type-II X-ray bursts from the rapid burster (MXB 1730-335) observed by the Hard X-ray Modulation Telescope (Insight-HXMT) and Swift/X-Ray Telescope (XRT). By stacking the long-duration bursts, we find for the first time that the hard X-rays are lagging behind the soft X-rays by 3 s. However, such a lag is not visible for the short-duration bursts, probably because of the poor statistics. For all bursts the energy spectrum is found to be nonthermal, thanks to the broadband coverage of Insight-HXMT. These findings provide new insights into the type-II bursts and require a temporally visible corona for possible interpretation.

Keywords: X-ray bursters
Nonthermal Velocity in the Transition Region of Active Regions and Its Center-to-limb Variation. We derive the nonthermal velocities (NTVs) in the transition region of an active region using the Si IV 1393.78 Å line observed by the Interface Region Imaging Spectrograph and compare them with the line-of-sight photospheric magnetic fields obtained by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. The active region consists of two strong field regions with opposite polarity, separated by a weak field corridor that widened as the active region evolved. The means of the NTV distributions in strong field regions (weak field corridors) range between ∼18-20 (16-18) km s-1, albeit the NTV maps show a much larger range. In addition, we identify a narrow lane in the middle of the corridor with significantly reduced NTV. The NTVs do not show a strong center-to-limb variation, albeit they show somewhat larger values near the disk center. The NTVs are well correlated with redshifts as well as line intensities. The results obtained here and those presented in our companion paper on Doppler shifts suggest two populations of plasma in the active region emitting in Si IV. The first population exists in the strong field regions and extends partway into the weak field corridor between them. We attribute this plasma to spicules heated to ∼0.1 MK (often called type II spicules). They have a range of inclinations relative to vertical. The second population exists in the center of the corridor, is relatively faint, and has smaller velocities, likely horizontal. These results provide further insights into the heating of the transition region.

Keywords: Solar coronal heating, Solar spicules, Solar physics, Solar active regions, Solar transition region
Statistics of Low Frequency Cutoffs for Type III Radio Bursts Observed by Parker Solar Probe during Its Encounters 1-5. The low frequency cutoffs flo and the observed plasma frequency fp of 176 type III radio bursts are investigated in this paper. These events are observed by the Parker Solar Probe when it is in the encounter phase from the first to the fifth orbit. The result shows that the distribution of cutoffs flo is widely spread between 200 kHz and 1.6 MHz. While the plasma frequency fp at the spacecraft is between 50 and 250 kHz, which is almost all smaller than flo. The result also shows that the maximum probability distribution of flo (∼680 kHz) is remarkably higher than that observed by Ulysses and Wind (∼100 kHz) in previous research. Three possible reasons, i.e., solar activity intensity, event electing criteria, and radiation attenuation effect, are also preliminarily discussed.

Keywords: Solar radio emission, Interplanetary physics
Astromers in the Radioactive Decay of r-process Nuclei. Certain nuclear isomers are well known to affect nucleosynthesis with important observable consequences (e.g., 26Al and 180Ta). We study the impact of nuclear isomers in the context of rapid neutron capture process (r-process) nucleosynthesis. We demonstrate that nuclear isomers are dynamically populated in the r process and that some are populated far from thermal equilibrium; this makes them astrophysical isomers, or "astromers." We compute thermally mediated transition rates between long-lived isomers and the corresponding ground states in neutron-rich nuclei. We calculate the temperature-dependent β-decay feeding factors, which represent the fraction of material going to each of the isomer and ground state daughter species from the β-decay parent species. We simulate nucleosynthesis following the decay of a solar-like r-process composition and include as separate species nuclear excited states with measured terrestrial half-lives greater than 100 μs. We introduce a new metric to identify those astromers most likely to be influential and summarize them in a table. Notable entries include many second peak nuclei (e.g., the Te isotopic chain) and previously overlooked isomers in stable nuclei (e.g., 119Sn, 131Xe, and 195Pt). Finally, we comment on the capacity of isomer production to alter radioactive heating in an r-process environment.

Keywords: R-process, Nuclear astrophysics, Nuclear physics