Sazuna/UAT_keywords huggingface dataset:
The Background Interstellar Medium as Observed from Off-order Low-resolution Spitzer-IRS Spectra. Spitzer "hidden" observations of the background are used to construct a catalog of 4090 spectra and examine the signature of polycyclic aromatic hydrocarbon (PAH) molecules and their connection to extinction by dust. A strong positive correlation is recovered between WISE12, E(B ‑ V), and the 11.2 μm PAH band. For 0.06 ≤ E(B ‑ V) ≤ 5.0, correlations of the 6.2, 11.2, and 12.7 μm PAH band are positive with E(B ‑ V). Three dust temperature regimes are revealed. Correlations with WISE12 are well constrained and that with 12.7/11.2 is flat. Decomposition with the NASA Ames PAH IR Spectroscopic Database reveals a tentative positive correlation between the 6.2/11.2 and the PAH ionization fraction, while that with 12.7/11.2 is slightly negative, suggesting PAH structural changes. The relation with PAH size and 6.2/11.2 is negative, while that with 12.7/11.2 is positive. Averaging spectra into five E(B ‑ V) and three T dust bins shows an evolution in PAH emission and variations in 12.7/11.2. Database-fits show an increase in f i and the PAH ionization parameter γ, but a more stable large PAH fraction. While the largest γs are associated with the highest T dust, there is no one-to-one correlation. The analysis is hampered by low-quality data at short wavelengths. There are indications that PAHs in the more-diffuse backgrounds behave differently from those in the general interstellar medium. However, they are often still associated with larger scale filamentary cloud-like structures. The spectra and auxiliary data have been made available through the Ames Background Interstellar Medium Spectral Catalog and may guide JWST programs.

Keywords: Interstellar dust, Polycyclic aromatic hydrocarbons, Astronomy databases, Infrared spectroscopy, Dust continuum emission, Interstellar medium
Silencing the Giant: Evidence of Active Galactic Nucleus Feedback and Quenching in a Little Red Dot at z = 4.13. The James Webb Space Telescope (JWST) has uncovered a ubiquitous population of dust-obscured compact sources at z ≳ 4. Many of these objects exhibit signs of active galactic nucleus (AGN) activity, making their study crucial for understanding the formation of supermassive black holes (SMBHs) and their growth with host galaxies. In this work, we examine low and medium-resolution JWST/NIRSpec spectra from the JADES GTO public data release in the GOODS-N field of a red, luminous (M B ∼ ‑22.2 mag) and compact (&lt;500 pc) source at z = 4.13. The rest-optical (λ rest &gt; 4000 Å) continuum of this source is strongly dominated by a massive (log10[M */M ⊙] ∼ 10.6), quenched (log10[sSFR/yr‑1] &lt; ‑11) galaxy, as indicated by the clear presence of a Balmer break and stellar absorption lines. Star formation history modeling reveals a starburst episode followed by rapid quenching about 200 Myr ago. The spectrum shows extremely broad (FWHM ∼2500 km s‑1) Hα emission and elevated optical line ratios, indicating an actively accreting SMBH. Moreover, our work has potentially revealed clear AGN signatures in the rest-UV in little red dots for the first time via the detection of a strong Lyα emission and a broad Mg II doublet. The derived black hole mass of log10(M BH/M ⊙) ∼ 7.3 results in M BH/M * ∼ 0.04%, consistent with the local relations, unlike the elevated ratios in other high-z reddened AGN. Finally, we use JWST data from AGN at z = 4–10 to explore an evolutionary link between high-z reddened AGN, early quiescent galaxies, and local ellipticals.

Keywords: Early universe, Quenched galaxies, Active galactic nuclei, Galaxy quenching, High-redshift galaxies
Modeling ALMA Observations of the Warped Molecular Gas Disk in the Red Nugget Relic Galaxy NGC 384. We present 0.″22 resolution CO(2─1) observations of the circumnuclear gas disk in the local compact galaxy NGC 384 with the Atacama Large Millimeter/submillimeter Array (ALMA). While the majority of the disk displays regular rotation with projected velocities rising to 370 km s−1, the inner ∼0.″5 exhibits a kinematic twist. We develop warped disk gas-dynamical models to account for this twist, fit those models to the ALMA data cube, and find a stellar mass-to-light ratio in the H band of M/L H = 1.34 ± 0.01 [1σ statistical] ±0.02 [systematic] M ⊙/L ⊙ and a supermassive black hole (BH) mass (M BH) of M BH  =(7.26−0.48+0.43[1σstatistical]−1.00+0.55[systematic])×108M⊙ . In contrast to most previous dynamical M BH measurements in local compact galaxies, which typically found over-massive BHs compared to the local BH mass−bulge luminosity and BH mass−bulge mass relations, NGC 384 lies within the scatter of those scaling relations. NGC 384 and other local compact galaxies are likely relics of z ∼ 2 red nuggets, and over-massive BHs in these relics indicate BH growth may conclude before the host galaxy stars have finished assembly. Our NGC 384 results may challenge this evolutionary picture, suggesting there may be increased scatter in the scaling relations than previously thought. However, this scatter could be inflated by systematic differences between stellar- and gas-dynamical measurement methods, motivating direct comparisons between the methods for NGC 384 and the other compact galaxies in the sample.

Keywords: Supermassive black holes, Molecular gas, Astronomy data modeling, Millimeter astronomy, Extragalactic astronomy, Scaling relations, Galaxy kinematics, Galaxy circumnuclear disk, Submillimeter astronomy, Early-type galaxies
The A<SUP>2</SUP>Π–X<SUP>2</SUP>Σ<SUP>+</SUP> Band System of ScO for M-type Star Spectral Analysis. M-type stars are the most abundant stars in our Galaxy. Their visible spectra are characterized by strong TiO and VO absorption bands with occasional ScO bands near 6000–6100 Å. This region corresponds to the A2Π–X2Σ+ band system and can be used to measure the abundance of ScO. In this work, a new Doppler-limited resolution spectrum of ScO obtained in a hollow-cathode experiment is presented. The A2Π–X2Σ+ electronic transition is analyzed with special care dedicated to fitting the  A'2Δ(v+2)  ∼ A2Π(v) perturbation. Spectroscopic constants of the A2Π(v) states are reported for v ≤ 9, and a partial fit of spectroscopic constants is made for the  A'2Δ(v)  states 2 ≤ v ≤ 6. The modeled interaction of the two states reproduces the experimental data remarkably well. New equilibrium constants are extracted from the fit. Band strengths are calculated with the help of a scaled transition dipole moment function, previously calculated with ab initio methods. Finally, a line list of the A2Π–X2Σ+ band system is provided, including Einstein A coefficients and oscillator strengths. Using this line list, the spectrum of ScO can be simulated for different temperature and pressure conditions in stellar atmospheres.

Keywords: Spectral line lists, Laboratory astrophysics
Experimental and Computational Study of Ethanolamine Ices under Astrochemical Conditions. Ethanolamine (NH2CH2CH2OH) has recently been identified in the molecular cloud G+0.693-0.027, situated in the SgrB2 complex in the Galactic center. However, its presence in other regions, and in particular in star-forming sites, is still elusive. Given its likely role as a precursor to simple amino acids, understanding its presence in the star-forming region is required. Here, we present the experimentally obtained temperature-dependent spectral features and morphological behavior of pure ethanolamine ices under astrochemical conditions in the 2–12 μm (MIR) and 120–230 nm (VUV) regions for the first time. These features would help in understanding its photochemical behavior. In addition, we present the first chemical models specifically dedicated to ethanolamine. These models include all the discussed chemical routes from the literature, along with the estimated binding energies and activation energies from quantum chemical calculations reported in this work. We have found that surface reactions CH2OH + NH2CH2 → NH2CH2CH2OH and NH2 + C2H4OH → NH2CH2CH2OH in warmer regions (60–90 K) could play a significant role in the formation of ethanolamine. Our modeled abundance of ethanolamine complements the upper limit of ethanolamine column density estimated in earlier observations in hot core/corino regions. Furthermore, we provide a theoretical estimation of the rotational and distortional constants for various species (such as HNCCO, NH2CHCO, and NH2CH2CO) related to ethanolamine that have not been studied in existing literature. This study could be valuable for identifying these species in the future.

Keywords: Molecular data, Infrared spectroscopy, Ice spectroscopy, Molecular spectroscopy, Interstellar abundances, Chemical abundances, Astrochemistry, Pre-biotic astrochemistry
On the Role of Noncircular Motions in MaNGA Galaxies. I. Global Properties. Noncircular (NC) motions represent the imprints of nonaxisymmetric structures in galaxies, providing opportunities to study the physical properties of gas departing from circular rotation. In this work, we have conducted a systematic study of the NC motions in a sample of 1624 gas-rich disk galaxies from the Mapping Nearby Galaxies at Apache Point Observatory (or MaNGA) Product Launch-11. By using the Hα velocity as a tracer of the disk rotation, we find indications that the amplitude of the NC motions is related to the stellar mass, with the low-mass and late-type galaxies the most affected. In our sample, we find ratios of NC to circular rotation ranging from 5% to 20%. By implementing harmonic models to include NC motions associated with spiral arms and stellar bars, we find that the rotational curves traced with Hα are barely affected by the NC motions induced by these structures. Consequently, in our sample, we do not find evidence that NC motions contribute to the scatter of the stellar Tully–Fisher relation. Our results suggest that NC motions might have a more localized effect in galaxies rather than a global one.

Keywords: Galaxies, Barred spiral galaxies, Interstellar dynamics, Spiral galaxies
Osaka Feedback Model. III. Cosmological Simulation CROCODILE. We introduce our new cosmological simulation data set CROCODILE, executed using the GADGET4-OSAKA smoothed particle hydrodynamics code. This simulation incorporates an updated supernova (SN) feedback model of Y. Oku et al. and an active galactic nuclei (AGN) feedback model. A key innovation in our SN feedback model is the integration of a metallicity- and redshift-dependent, top-heavy initial mass function. Our SN model introduces a new consideration that results in an order of magnitude difference in the energy injection rate per unit stellar mass formed at high redshift. The CROCODILE data set is comprehensive, encompassing a variety of runs with diverse feedback parameters. This allows for an in-depth exploration of the relative impacts of different feedback processes in galactic evolution. Our initial comparisons with observational data, spanning the galaxy stellar mass function, the star formation main sequence, and the mass–metallicity relation, show promising agreement, especially for the Fiducial run. These results establish a solid foundation for our future work. We find that SN feedback is a key driver in the chemical enrichment of the intergalactic medium (IGM). Additionally, the AGN feedback creates metal-rich, bipolar outflows that extend and enrich the circumgalactic medium and IGM over a few Mpc scales.

Keywords: Hydrodynamical simulations, Galaxy formation, Stellar feedback, Chemical enrichment, Star formation, Active galactic nuclei, Galaxy evolution, Intergalactic medium
Forecasts for Helium Reionization Detection with Fast Radio Bursts in the Era of Square Kilometre Array. The observed dispersion measures (DMs) of fast radio bursts (FRBs) are a good indicator of the amount of ionized material along the propagation paths. In this work, we present a forecast of He II reionization detection using the DM and redshift measurements of FRBs from the upcoming Square Kilometre Array (SKA). Assuming a model of the Universe in which He II reionization occurred at a specific redshift  zre , we analyze what extent the signal-to-noise ratio (S/N) for the detection of the amplitude of reionization can be achieved in the era of SKA. Using 106 mock FRB data from a 1 year observation of the second phase of SKA, we find that the S/N for detecting He II reionization can approach the 32–50σ level, and the uncertainty on the reionization redshift can be constrained to be  σ(zre)≈0.022‑0.031 , depending on the assumed FRB redshift distribution. This is the first quantitative analysis on the detection significance of He II reionization in the SKA era. We also examine the influence of different fiducial  zre  values, finding that this effect has a modest impact on the forecasts. Our results demonstrate the potentially remarkable capability of SKA-era FRBs in constraining the epoch of He II reionization.

Keywords: Intergalactic medium, Reionization, Observational cosmology, Radio transient sources
Simultaneous X-Ray and Optical Polarization Observations of the Blazar Mrk 421. We present near-simultaneous X-ray and optical polarization measurements in the high synchrotron peaked (HSP) blazar Mrk 421. The X-ray polarimetric observations were carried out using Imaging X-ray Polarimetry Explorer (IXPE) on 2023 December 6. During IXPE observations, we also carried out optical polarimetric observations using 104 cm Sampurnanand telescope at Nainital and multiband optical imaging observations using 2 m Himalayan Chandra Telescope at Hanle. From model-independent analysis of IXPE data, we detected X-ray polarization with degree of polarization (ΠX) of 8.5% ± 0.5% and an electric vector position angle (ΨX) of 10.°6 ± 1.°7 in the 2‑8 keV band. From optical polarimetry on 2023 December 6, in B, V, and R bands, we found values of Π B  = 4.27% ± 0.32%, Π V  = 3.57% ± 0.31%, and Π R  = 3.13% ± 0.25%. The value of Π B  is greater than that observed at longer optical wavelengths, with the degree of polarization suggesting an energy-dependent trend, gradually decreasing from higher to lower energies. This is consistent with that seen in other HSP blazars and favors a stratified emission region encompassing a shock front. The emission happening in the vicinity of the shock front will be more polarized due to the ordered magnetic field resulting from shock compression. The X-ray emission, involving high-energy electrons, originates closer to the shock front than the optical emission. The difference in the spatial extension could plausibly account for the observed variation in polarization between X-ray and optical wavelengths. This hypothesis is further supported by the broadband spectral energy distribution modeling of the X-ray and optical data.

Keywords: BL Lacertae objects, Blazars, Active galactic nuclei, X-ray sources, Polarimetry
He-accreting Oxygen–Neon White Dwarfs and Accretion-induced Collapse Events. It has been widely accepted that mass-accreting white dwarfs (WDs) are the progenitors of Type Ia supernovae (SNe) or electron-capture supernovae. Previous work has shown that the accretion rate could affect the elemental abundance on the outer layers of CO WDs, and therefore affect the observational characteristics after they exploded as SNe Ia. However, it has not been well studied how elemental abundance changes on the outer layers of He-accreting ONe WDs as they approach the Chandrasekhar mass limit. In this paper, we investigated the evolution of He-accreting ONe WDs with MESA. We found that a CO-rich mantle will accumulate beneath the He layers resulting from the He burning, after which the ignition of the CO-rich mantle could transform carbon into silicon (Si). The amount of Si produced by carbon burning is strongly anticorrelated with the accretion rate. As the ONe WD nearly approaches the Chandrasekhar mass limit (M ch) through accretion, it is likely to undergo accretion-induced collapse, resulting in the formation of a neutron star.

Keywords: White dwarf stars, Supernovae, Stellar evolution
Stacking and Analyzing MOSDEF Galaxies by Spectral Types: Implications for Dust Geometry and Galaxy Evolution. We examine star formation and dust properties for a sample of 660 galaxies at 1.37 ≤ z ≤ 2.61 in the MOSDEF survey by dividing them into groups with similarly shaped spectral energy distributions (SEDs). For each group, we combine the galaxy photometry into a finely sampled composite SED, and stack their spectra. This method enables the study of more complete galaxy samples, including galaxies with very faint emission lines. We fit these composite SEDs with Prospector to measure the stellar attenuation and SED-based star formation rates (SFRs). We also derive emission-line properties from the spectral stacks, including Balmer decrements, dust-corrected SFRs, and metallicities. We find that stellar attenuation correlates most strongly with mass, while nebular attenuation correlates strongly with both mass and SFR. Furthermore, the excess of nebular compared to stellar attenuation correlates most strongly with SFR. The highest SFR group has 2 mag of excess nebular attenuation. Our results are consistent with a model in which star-forming regions become more dusty as galaxy mass increases. To explain the increasing excess nebular attenuation, we require a progressively larger fraction of star formation to occur in highly obscured regions with increasing SFR. This highly obscured star formation could occur in dusty clumps or central starbursts. Additionally, as each galaxy group represents a different evolutionary stage, we study their locations on the UVJ and SFR-mass diagrams. As mass increases, metallicity and dust attenuation increase, while sSFR decreases. However, the most massive group moves towards the quiescent region of the UVJ diagram, while showing less obscuration, potentially indicating removal of dust.

Keywords: Galaxy formation, Galaxy structure, Galaxy evolution, Star forming regions
Memory in the Burst Occurrence of Repeating Fast Radio Bursts. Understanding the nature of repeating fast radio bursts (FRBs) is crucial for probing their underlying physics. In this work, we analyze the waiting time statistics between bursts of three repeating FRBs from four data sets. We find a universally pronounced dependency of the waiting times on the previous time interval (denoted as λ 0). We observe a temporal clustering, where short waiting times tend to be followed by short ones and long by long, comparative to their mean value. This memory dependency is manifested in the conditional mean waiting time as well as in the conditional mean residual time to the next burst, both of which increase in direct proportion to λ 0. Consequently, the likelihood of experiencing a subsequent FRB burst within a given time window after the preceding burst is generally influenced by the burst history. We reveal, for the first time, that these memory effects are present in the scale-invariant preconditioned waiting time distribution. We show that the memory effect provides a unified description of waiting times that may account for both the repeating FRBs and the apparently nonrepeating FRBs (i.e., those only observed one time). These results shed new light on the mechanism of FRBs.

Keywords: High energy astrophysics, Transient sources, Burst astrophysics, Radio bursts, Radio transient sources
Cross-correlating Dark Sirens and Galaxies: Constraints on H <SUB>0</SUB> from GWTC-3 of LIGO–Virgo–KAGRA. We apply the cross-correlation technique to infer the Hubble constant (H 0) of the Universe using gravitational-wave (GW) sources without electromagnetic counterparts (dark sirens) from the third GW Transient Catalog (GWTC-3) and the photometric galaxy surveys 2MPZ and WISE-SuperCOSMOS, and combine these with the bright siren measurement of H 0 from GW170817. The posterior on H 0 with only dark sirens is uninformative due to the small number of well-localized GW sources. Using the eight well-localized dark sirens and the binary neutron star GW170817 with electromagnetic counterpart, we obtain a value of the Hubble constant  H0=75.4‑6+11  km s‑1 Mpc‑1 (median and 68.3% equal-tailed interval) after marginalizing over the matter density and the GW bias parameters. This measurement is mostly driven by the bright siren measurement, and any constraint from dark sirens is not statistically significant. In the future, with more well-localized GW events, the constraints on expansion history will improve.

Keywords: Cosmology, Observational cosmology
Modeling the Energy-dependent Broadband Variability in the Black Hole Transient GX 339–4 Using AstroSat and NICER. We present a spectro-timing analysis of the black hole X-ray transient GX 339–4 using simultaneous observations from AstroSat and the Neutron Star Interior Composition Explorer (NICER) during the 2021 outburst period. The combined spectrum obtained from NICER, Large Area X-ray Proportional Counter and SXT data is effectively described by a model comprising a thermal disk component, hard Comptonization component, and reflection component with an edge. Our analysis of the AstroSat and NICER spectra indicates the source to be in a low/hard state, with a photon index of ∼1.64. The power density spectra obtained from both AstroSat and NICER observations exhibit two prominent broad features at 0.22 Hz and 2.94 Hz. We generated energy-dependent time lag and fractional root mean square (frms) at both frequencies in a broad energy range of 0.5–30 keV and found the presence of hard lags along with a decrease in variability at higher energy levels. Additionally, we discovered that the correlated variations in accretion rate, inner disk radius, coronal heating rate, and the scattering fraction, along with a delay between them, can explain the observed frms and lag spectra for both features.

Keywords: Accretion, Black hole physics, X-ray astronomy, Stellar accretion disks, High energy astrophysics, Low-mass x-ray binary stars
Common Envelopes, Gamma Rays, and Sudden Spectral Changes of Novae. A common envelope (CE) is proposed as the origin of the early post-outburst spectra of many novae. A simple model is proposed to explain the properties of the CE based on the emission line strengths and an assumed density distribution. Rapid changes in the spectrum during post-outburst decline are suggested as possible evidence for a CE. Time-resolved spectra from the ARAS group show sudden spectral shifts that are correlated with detected γ-ray emission, suggestive of its possible origin on the white dwarf that produces a change in condition within the CE. Episodic mass loss, formation of transient heavy element absorption systems, and dissipation of the CE may possibly be triggered by γ-ray emission.

Keywords: Novae