adsabs/SciX_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
Directional Association of TeV to PeV Astrophysical Neutrinos with Radio Blazars

Recently we have shown that high-energy neutrinos above 200 TeV detected by IceCube are produced within several parsecs in the central regions of radio-bright blazars, that is active galactic nuclei with jets pointing toward us. To independently test this result and extend the analysis to a wider energy range, we use public data for all neutrino energies from seven years of IceCube observations. The IceCube point-source likelihood map is analyzed against the positions of blazars from a statistically complete sample selected according to their compact radio flux density. The latter analysis delivers a 3.0σ significance, with the combined post-trial significance of both studies being 4.1σ. The correlation is driven by a large number of blazars. Together with fainter but physically similar sources not included in the sample, they may explain the entire IceCube astrophysical neutrino flux as derived from muon-track analyses. The neutrinos can be produced in interactions of relativistic protons with X-ray self-Compton photons in parsec-scale blazar jets.

Keywords: neutrino astronomy; active galaxies; galaxy jets; quasars; radio continuum emission
Analysis of Membership Probability in Nearby Young Moving Groups with Gaia DR2

We analyze the membership probability of young stars belonging to nearby moving groups with Gaia DR2 data. The sample of 1429 stars was identified from "The Catalog of Suspected Nearby Young Moving Group Stars." Good-quality parallax and proper motion values were retrieved for 890 stars from the Gaia DR2 database. The analysis for membership probability is performed in the framework of the LACEwING algorithm. From the analysis it is confirmed that 279 stars do not belong to any of the known moving groups. We estimated the U, V, W space velocity values for 250 moving group members, which were found to be more accurate than previous values listed in the literature. The velocity ellipses of all the moving groups are well constrained within the "good box," a widely used criterion to identify moving group members. The age of moving group members are uniformly estimated from the analysis of the Gaia color-magnitude diagram with MIST isochrones. We found a spread in the age distribution of stars belonging to some moving groups, which needs to be understood from further studies.

Keywords: stellar kinematics; proper motions; radial velocity; stellar associations
Comparative Study of Low-temperature Opacities with GARSTEC Models

We present a comparative study of the effect of low-temperature opacities on stellar models up to the Red Giant branch (RGB), computed with the GARching STellar Evolution Code. We have used two sets of low-temperature opacities; ÆSOPUS (Æ) from the University of Padova and those from the Wichita State University group (F05). In the relevant range of temperatures for this study, $\mathrm{log}{\kappa }^{\unicode{x000C6}}$ < $\mathrm{log}{\kappa }^{{\rm{F}}05}$ . Therefore, to compare stellar evolutionary tracks, we performed a solar calibration of the α mlt, for each set of low-temperature opacities. After carrying such a calibration, we find that stellar evolutionary tracks are almost unaffected by the choice of low-temperature opacities, with largest variations of 25-30 K at the latest evolutionary stages of the RGB phase.

Keywords: astronomy data modeling; stellar astronomy; stellar physics; stellar evolution; stellar properties; hertzsprung russell diagram
Investigating the Impact of Atomic Data Uncertainties on the Measured Physical Parameters of the Perseus Galaxy Cluster

Accurate atomic data and plasma models are essential for interpreting the upcoming high-quality spectra from missions like XRISM and Athena. Estimating physical quantities, like temperature, abundance, turbulence, and the resonance scattering factor, is highly dependent on the underlying atomic data. We use the AtomDB tool variableapec to estimate the impact of atomic data uncertainties in Einstein A coefficients, collisional rate coefficients, and the ionization and recombination rates of H-, He-, and Li-like iron in modeling the spectrum of Perseus observed by Hitomi. The best-fit temperatures, abundances, resonance scattering factors, and turbulence parameters including atomic data uncertainties vary by approximately 17%, 35%, 30%, and 3%, respectively, from the best-fit temperatures, abundances, RS factors, and turbulence parameters estimated without atomic data uncertainties. These indicate that approximately 32%, 35%, and 25% of the best-fit temperatures, abundances, and resonance scattering factors when including uncertainties lie outside the 3σ error regions of their corresponding best-fit values computed with zero atomic data errors. Expanding the energy range to 1.8–20.0 keV shows less variability, with 26% of the abundances and 22% of the resonance scattering factors lying outside the 3σ errors of the best-fit values. We also studied correlations between physical parameters and atomic rate uncertainties to identify key atomic quantities requiring precise lab measurements. We report negative correlations between the best-fit temperatures and the z (1s2s 3S1 → 1s2) collisional rate coefficients, abundances and y (1s2p 3P1 → 1s2) collisional rate coefficients, and abundances and z collisional rate coefficients, and a positive correlation between the resonance scattering factors and the w (1s2p 1P1 → 1s2) collisional rate coefficients.

Keywords: x-ray astronomy; galaxy clusters; atomic spectroscopy
ALMA Observations of the Extraordinary Carina Pillars: HH 901/902

We present Atacama Large Millimeter/Submillimeter Array 1.3 mm continuum and C18O(2-1), N2D+(3-2), 13CS(5-4), and 12CO(2-1) line sensitive and high angular resolution (∼0"3) observations of the famous Carina pillars and protostellar objects HH 901/902. Our observations reveal for the first time, the bipolar CO outflows and the dusty disks (plus envelopes) that are energizing the extended and irradiated Herbig-Haro (HH) objects far from the pillars. We find that the masses of the disks+envelopes are about 0.1 M⊙ and that the bipolar outflows are between 10-3 and 10-4 M⊙, which suggests that they could be low- or maybe intermediate-mass protostars. Moreover, we suggest that these young low-mass stars are likely embedded Class 0/I protostars with high-accretion rates. We also show the kinematics of the gas in the pillars together with their respective gas masses (0.1-0.2 M⊙). We estimate that the pillars will be photoevaporated in 104 to 105 yr by the massive and luminous stars located in the Trumpler 14 cluster. Finally, given the short photoevaporated timescales and that the protostars in these pillars are still very embedded, we suggest that the disks inside of the pillars will be quickly affected by the radiation of the massive stars, forming proplyds, like those observed in Orion.

Keywords: proplyds; interstellar molecules; aperture synthesis; stellar jets
KLLR: A Scale-dependent, Multivariate Model Class for Regression Analysis

The underlying physics of astronomical systems govern the relation between their measurable properties. Consequently, quantifying the statistical relationships between system-level observable properties of a population offers insights into the astrophysical drivers of that class of systems. While purely linear models capture behavior over a limited range of system scale, the fact that astrophysics is ultimately scale dependent implies the need for a more flexible approach to describing population statistics over a wide dynamic range. For such applications, we introduce and implement a class of kernel localized linear regression (KLLR) models. KLLR is a natural extension to the commonly used linear models that allows the parameters of the linear model-normalization, slope, and covariance matrix-to be scale dependent. KLLR performs inference in two steps: (1) it estimates the mean relation between a set of independent variables and a dependent variable and; (2) it estimates the conditional covariance of the dependent variables given a set of independent variables. We demonstrate the model's performance in a simulated setting and showcase an application of the proposed model in analyzing the baryonic content of dark matter halos. As a part of this work, we publicly release a Python implementation of the KLLR method.

Keywords: astrostatistics; astrostatistics tools; astronomy software; computational astronomy; astronomy data analysis
Understanding the Deflection of the "Cartwheel CME": Data Analysis and Modeling

We study the low corona evolution of the "Cartwheel" coronal mass ejection (CME; 2008 April 9) by reconstructing its three-dimensional path and modeling it with magnetohydrodynamic simulations. This event exhibited a double deflection that has been reported and analyzed in previous works but whose underlying cause remained unclear. The Cartwheel CME traveled toward a coronal hole (CH) and against the magnetic gradients. Using a high-cadence, full-trajectory reconstruction, we accurately determine the location of the magnetic flux rope (MFR) and, consequently, the magnetic environment in which it is immersed. We find a pseudostreamer (PS) structure whose null point may be responsible for the complex evolution of the MFR at the initial phase. From the preeruptive magnetic field reconstruction, we estimate the dynamic forces acting on the MFR and provide a new physical insight into the motion exhibited by the 2008 April 9 event. By setting up a similar magnetic configuration in a 2.5D numerical simulation we are able to reproduce the observed behavior, confirming the importance of the PS null point. We find that the magnetic forces directed toward the null point cause the first deflection, directing the MFR toward the CH. Later, the magnetic pressure gradient of the CH produces the reversal motion of the MFR.

Keywords: solar prominences; solar magnetic fields; solar coronal mass ejections; magnetohydrodynamical simulations
The Colorado Ultraviolet Transit Experiment Mission Overview

Atmospheric escape is a fundamental process that affects the structure, composition, and evolution of many planets. The signatures of escape are detectable on close-in, gaseous exoplanets orbiting bright stars, owing to the high levels of extreme-ultraviolet irradiation from their parent stars. The Colorado Ultraviolet Transit Experiment (CUTE) is a CubeSat mission designed to take advantage of the near-ultraviolet stellar brightness distribution to conduct a survey of the extended atmospheres of nearby close-in planets. The CUTE payload is a magnifying near-ultraviolet (2479-3306 Å) spectrograph fed by a rectangular Cassegrain telescope (206 mm × 84 mm); the spectrogram is recorded on a back-illuminated, UV-enhanced CCD. The science payload is integrated into a 6U Blue Canyon Technology XB1 bus. CUTE was launched into a polar, low-Earth orbit on 2021 September 27 and has been conducting this transit spectroscopy survey following an on-orbit commissioning period. This paper presents the mission motivation, development path, and demonstrates the potential for small satellites to conduct this type of science by presenting initial on-orbit science observations. The primary science mission is being conducted in 2022-2023, with a publicly available data archive coming online in 2023.

Keywords: near ultraviolet astronomy; transits; exoplanet atmospheres
A Survey for High-redshift Gravitationally Lensed Quasars and Close Quasar Pairs. I. The Discoveries of an Intermediately Lensed Quasar and a Kiloparsec-scale Quasar Pair at z 5

We present the first results from a new survey for high-redshift (z ≳ 5) gravitationally lensed quasars and close quasar pairs. We carry out candidate selection based on the colors and shapes of objects in public imaging surveys, then conduct follow-up observations to confirm the nature of high-priority candidates. In this paper, we report the discoveries of J0025-0145 (z = 5.07), which we identify as an intermediately lensed quasar, and J2329-0522 (z = 4.85), which is a kiloparsec-scale close quasar pair. The Hubble Space Telescope (HST) image of J0025-0145 shows a foreground lensing galaxy located 0.″6 away from the quasar. However, J0025-0145 does not exhibit multiple lensed images of the quasar, and we identify J0025-0145 as an intermediate lensing system (a lensing system that is not multiply imaged but has a significant magnification). The spectrum of J0025-0145 implies an extreme Eddington ratio if the quasar luminosity is intrinsic, which could be explained by a large lensing magnification. The HST image of J0025-0145 also indicates a tentative detection of the quasar host galaxy in the rest-frame UV, illustrating the power of lensing magnification and distortion in studies of high-redshift quasar host galaxies. Object J2329-0522 consists of two resolved components with significantly different spectral properties and a lack of lensing galaxy detection under subarcsecond seeing. We identify it as a close quasar pair, which is the highest confirmed kiloparsec-scale quasar pair to date. We also report four lensed quasars and quasar pairs at 2 < z < 4 and discuss possible improvements to our survey strategy.

Keywords: quasars; double quasars; gravitational lensing
On the Gamma-Ray Emission of the Andromeda Galaxy M31

Using the γ-ray data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (Fermi) for ~14 yr, we examine the high-energy emission emanating from the center of the Andromeda galaxy M31. Different from previously reported results, which show a seemingly extended source, we instead find two individual point sources, one consistent with being at the center and one 0.°4 southeast of the center. The emission of the former is well described using a log-parabola model, similar to those of previous studies, and that of the latter can be fitted with a power law. We discuss the possible origins for the two sources. M31's central source, now consistent with being a point source, necessitates a revisit of its previously discussed originations with this new property taken into consideration, in particular those cosmic rays or dark matter scenarios involving extended source distributions. The SE source appears to have a projected distance of ~6 kpc from M31's center, and the investigation is required as to whether it is a source locally associated with M31, or is instead a background extragalactic one.

Keywords: gamma-ray sources; andromeda galaxy
The Type Ibn Supernova 2019kbj: Indications for Diversity in Type Ibn Supernova Progenitors

Type Ibn supernovae (SNe) are a rare class of stellar explosions whose progenitor systems are not yet well determined. We present and analyze observations of the Type Ibn SN 2019kbj, and model its light curve in order to constrain its progenitor and explosion parameters. SN 2019kbj shows roughly constant temperature during the first month after peak, indicating a power source (likely circumstellar material interaction) that keeps the continuum emission hot at ~15,000 K. Indeed, we find that the radioactive decay of 56Ni is disfavored as the sole power source of the bolometric light curve. A radioactive decay + circumstellar material (CSM) interaction model, on the other hand, does reproduce the bolometric emission well. The fits prefer a uniform-density CSM shell rather than CSM due to a steady mass-loss wind, similar to what is seen in other Type Ibn SNe. The uniform-density CSM shell model requires ~0.1 M ⊙ of 56Ni and ~1 M ⊙ total ejecta mass to reproduce the light curve. SN 2019kbj differs in this manner from another Type Ibn SN with derived physical parameters, SN 2019uo, for which an order of magnitude lower 56Ni mass and larger ejecta mass were derived. This points toward a possible diversity in SN Ibn progenitor systems and explosions.

Keywords: supernovae; core-collapse supernovae; massive stars
Optical and Near-infrared Pulsation Properties of RR Lyrae and Population II Cepheid Variables in the Messier 15 Globular Cluster

Messier 15 (NGC 7078) is an old and metal-poor post core-collapse globular cluster that hosts a rich population of variable stars. We report new optical (gi) and near-infrared (NIR, JKs) multi-epoch observations for 129 RR Lyrae, 4 Population II Cepheids (3 BL Herculis, 1 W Virginis), and 1 anomalous Cepheid variable candidate in M15 obtained using the MegaCam and the WIRCam instruments on the 3.6 m Canada-France-Hawaii Telescope. Multi-band data are used to improve the periods and classification of variable stars, and determine accurate mean magnitudes and pulsational amplitudes from the light curves fitted with optical and NIR templates. We derive optical and NIR period-luminosity relations for RR Lyrae stars which are best constrained in the Ks band, ${m}_{{K}_{s}}=-2.333\,(0.054)\mathrm{log}P+13.948\,(0.015)$ with a scatter of only 0.037 mag. Theoretical and empirical calibrations of RR Lyrae period-luminosity-metallicity relations are used to derive a true distance modulus to M15: 15.196 ± 0.026 (statistical) ± 0.039 (systematic) mag. Our precise distance moduli based on RR Lyrae stars and Population II Cepheid variables are mutually consistent and agree with recent distance measurements in the literature based on Gaia parallaxes and other independent methods.

Keywords: rr lyrae variable stars; stellar pulsations; globular star clusters; distance indicators
JEMS: A Deep Medium-band Imaging Survey in the Hubble Ultra Deep Field with JWST NIRCam and NIRISS

We present JWST Extragalactic Medium-band Survey, the first public medium-band imaging survey carried out using JWST/NIRCam and NIRISS. These observations use ~2 and ~4 μm medium-band filters (NIRCam F182M, F210M, F430M, F460M, F480M; and NIRISS F430M and F480M in parallel) over 15.6 arcmin2 in the Hubble Ultra Deep Field (UDF), thereby building on the deepest multiwavelength public data sets available anywhere on the sky. We describe our science goals, survey design, NIRCam and NIRISS image reduction methods, and describe our first data release of the science-ready mosaics, which reach 5σ point-source limits (AB mag) of ~29.3-29.4 in 2 μm filters and ~28.2-28.7 at 4 μm. Our chosen filters create a JWST imaging survey in the UDF that enables novel analysis of a range of spectral features potentially across the redshift range of 0.3 < z < 20, including Paschen-α, Hα+[N II], and [O III]+Hβ emission at high spatial resolution. We find that our JWST medium-band imaging efficiently identifies strong line emitters (medium-band colors >1 mag) across redshifts 1.5 < z < 9.3, most prominently Hα+[N II] and [O III]+Hβ. We present our first data release including science-ready mosaics of each medium-band image available to the community, adding to the legacy value of past and future surveys in the UDF. This survey demonstrates the power of medium-band imaging with JWST, informing future extragalactic survey strategies using JWST observations.

Keywords: emission line galaxies; high-redshift galaxies; redshift surveys; extragalactic astronomy
Dust Destruction by Charging: A Possible Origin of Gray Extinction Curves of Active Galactic Nuclei

Observed extinction curves of active galactic nuclei (AGNs) are significantly different from those observed in the Milky Way. The observations require preferential removal of small grains at the AGN environment; however, the physics for this remains unclear. In this paper, we propose that dust destruction by charging, or Coulomb explosion, may be responsible for AGN extinction curves. Harsh AGN radiation makes a dust grain highly charged through photoelectric emission, and grain fission via Coulomb explosion occurs when the electrostatic tensile stress of a charge grain exceeds its tensile strength. We show that Coulomb explosion can preferentially remove both small silicate and graphite grains and successfully reproduce both flat extinction curve and the absence of 2175 Å bump.

Keywords: active galactic nuclei; astrophysical dust processes; ultraviolet extinction
GW190521: Orbital Eccentricity and Signatures of Dynamical Formation in a Binary Black Hole Merger Signal

Pair-instability supernovae are thought to restrict the formation of black holes in the mass range $\sim 50\mbox{--}135\,{M}_{\odot }$ . However, black holes with masses within this "high mass gap" are expected to form as the remnants of binary black hole mergers. These remnants can merge again dynamically in densely populated environments such as globular clusters. The hypothesis that the binary black hole merger GW190521 formed dynamically is supported by its high mass. Orbital eccentricity can also be a signature of dynamical formation, since a binary that merges quickly after becoming bound may not circularize before merger. In this work, we measure the orbital eccentricity of GW190521. We find that the data prefer a signal with eccentricity $e\geqslant 0.1$ at 10 Hz to a nonprecessing, quasi-circular signal, with a log Bayes factor $\mathrm{ln}{ \mathcal B }=5.0$ . When compared to precessing, quasi-circular analyses, the data prefer a nonprecessing, $e\geqslant 0.1$ signal, with log Bayes factors $\mathrm{ln}{ \mathcal B }\approx 2$ . Using injection studies, we find that a nonspinning, moderately eccentric (e = 0.13) GW190521-like binary can be mistaken for a quasi-circular, precessing binary. Conversely, a quasi-circular binary with spin-induced precession may be mistaken for an eccentric binary. We therefore cannot confidently determine whether GW190521 was precessing or eccentric. Nevertheless, since both of these properties support the dynamical formation hypothesis, our findings support the hypothesis that GW190521 formed dynamically.

Keywords: black holes; compact objects; high energy astrophysics; dynamical evolution; eccentricity; gravitational wave astronomy; gravitational waves; gravitational wave sources