Sazuna/UAT_keywords huggingface dataset:
Linking Stellar Populations to H II Regions across Nearby Galaxies. II. Infrared Reprocessed and UV Direct Radiation Pressure in H II Regions. Radiation pressure is a key mechanism by which stellar feedback disrupts molecular clouds and drives H II region expansion. This includes direct radiation pressure exerted by UV photons on dust grains, pressure associated with photoionization, and infrared (IR) radiation pressure on grains due to dust-reprocessed IR photons. We present a new method that combines high-resolution mid-IR luminosities from JWST-MIRI, optical attenuation, and nebular line measurements from the Very Large Telecope Multi-Unit Spectroscopic Explorer (VLT-MUSE), and the Hubble Space Telescope (HST) Hα-based region sizes to estimate the strength of radiation pressure in ≍18,000 H II regions across 19 nearby star-forming galaxies. This is the most extensive and direct estimate of these terms beyond the Local Group to date. In the disks of galaxies, we find that the total reprocessed IR pressure is on average 5% of the direct UV radiation pressure. This fraction rises to 10% in galaxy centers. We expect reprocessed IR radiation pressure to dominate over UV radiation pressure in regions where  . Radiation pressure due to H ionizations is lower than pressure on dust in our sample, but appears likely to dominate the radiation pressure budget in dwarf galaxies similar to the Small Magellanic Cloud. The contribution from all radiation pressure terms appears to be subdominant compared to thermal pressure from ionized gas, reinforcing the view that radiation pressure is most important in compact, heavily embedded, and young regions.

Keywords: Dust physics, Stellar feedback, Infrared astronomy, Interstellar medium, Extragalactic astronomy, H II regions
Magnetic Field Structures In and Around Seyfert Galaxy Outflows. We present radio polarimetric images of 12 Seyfert and low-ionization nuclear emission-line region (LINER) galaxies belonging to the Centre for Astrophysics +12 μm sample exhibiting kiloparsec-scale radio outflows (KSRs). These observations have been carried out at 10 GHz with the Karl G. Jansky Very Large Array in D array and at 1.4 GHz with the BnA → A array configurations. We find signatures of organized magnetic (B) field structures in the cores, jets, and lobes of these galaxies. The linear polarization fraction varies from a few percent in the cores to 47% ± 18% in the lobes. The inferred B fields are toroidal in the cores of several sources making them consistent with the presence of either a sheath-like or a wind-like component surrounding the jet. The in-band spectral index images typically show the presence of flat/inverted spectrum cores and steep spectrum lobes. Radio cores with flatter spectra are found to have lower Eddington ratios, while the steeper ones have higher. A strong correlation is observed between the Seyfert/LINER radio outflow properties and the mass of the supermassive black holes; correlations with Eddington ratios are weaker. We find signatures of jet-medium interaction and both positive and negative active galactic nuclei (AGN) feedback in these sources. Overall, our study indicates that radio-quiet AGN with KSRs possess radio outflows driven by magnetic fields anchored to their black hole—accretion disk systems, which significantly impact their environments.

Keywords: AGN host galaxies, Radio jets, Radio lobes, LINER galaxies, Seyfert galaxies, Active galactic nuclei, Interstellar medium, Polarimetry, Extragalactic magnetic fields
Metis Observations of Alfvénic Outflows Driven by Interchange Reconnection in a Pseudostreamer. This study presents observations of a large pseudostreamer solar eruption and, in particular, the post-eruption relaxation phase, as captured by Metis, on board the Solar Orbiter, on 2022 October 12, during its perihelion passage. Utilizing total-brightness data, we observe the outward propagation of helical features up to 3 solar radii along a radial column that appears to correspond to the stalk of the pseudostreamer. The helical structures persisted for more than 3 hr following a jet-like coronal mass ejection associated with a polar crown prominence eruption. A notable trend is revealed: the inclination of these features decreases as their polar angle and height increase. Additionally, we measured their helix pitch. Despite the 2 minute time cadence limiting direct correspondence among filamentary structures in consecutive frames, we find that the Metis helical structure may be interpreted as a consequence of twist (nonlinear torsional Alfvén waves) and plasma liberated by interchange reconnection. A comparison was performed between the helix parameters as outlined by fine-scale outflow features and those obtained from synthetic white-light images derived from the high-resolution magnetohydrodynamics simulation of interchange reconnection in a pseudostreamer topology by P. F. Wyper et al. A remarkable similarity between the simulation-derived images and the observations was found. We conjecture that these Metis observations may represent the upper ends of the spatial and energy scales of the interchange reconnection process that has been proposed recently as the origin of the Alfvénic solar wind.

Keywords: Solar wind
When is a Bulge Not a Bulge? Revealing the Satellite Nature of NGC 5474's Bulge. A satellite galaxy of the nearby spiral M101, NGC 5474 has a prominent bulge offset from the kinematic center of the underlying star-forming disk that has gained attention in recent years. Recent studies have proposed that this putative offset bulge is not a classical bulge within the plane of the disk but instead a dwarf companion galaxy along the line of sight. Using integral field spectroscopy data taken as part of the PPak IFS Nearby Galaxies Survey (PINGS), we perform the first analysis of the stellar and gas kinematics of this putative bulge (PB) and portions of the disk. We find a radial velocity offset of ∼24 km s‑1 between the emission lines produced by the disk H II regions and the absorption lines produced by the PB stellar component. We interpret this velocity offset as evidence that the PB and disk are two separate objects, the former orbiting around the latter, supporting simulations and observations of this peculiar system. We attempt to place this external companion into the context of the M101 Group and the M101-NGC 5474 interaction.

Keywords: Galaxy spectroscopy, Galaxy interactions, Galaxy kinematics, Galaxy evolution
Where Has All the R-process Gone? Timescales for Gamma-Ray Burst Kilonovae to Enrich Their Host Galaxies. Neutron star (NS) mergers are currently the only observed source of r-process production in the Universe. Yet, it is unclear how much r-process mass from these mergers is incorporated into star-forming gas to enrich stars. This is crucial to consider as all other r-process mass estimates in the Universe beyond Earth are based on stellar r-process abundances. Here, we explore the extent to which merger location and host-galaxy properties affect the incorporation of r-process elements into star-forming gas, and quantify an "enrichment" timescale to account for this process. To put this timescale in context, we analyze a population of 12 gamma-ray bursts (GRBs) with probable associations to r-process kilonovae (GRB-KNe) and 74 short GRBs without claimed KNe, including new nonparametric star formation histories for the GRB-KN hosts. We find the enrichment timescales for this sample are between ≈7 Myr and 1.6 Gyr, suggesting that environmental enrichment is delayed from NS merger occurrence. Moreover, we find a correlation between the amount of environmental enrichment from a single event and increasing host specific star formation rate (sSFR), and little correlation with stellar mass and GRB galactocentric offset. Environments with low sSFRs (&lt;10‑10.5 yr‑1), which comprise 18% of short-GRB hosts and the host of GW170817, will have little to no capacity for stellar enrichment. Our results indicate that not all r-process from NS mergers is incorporated into newly forming stars, and instead some remains "lost" to the circumgalactic medium or intergalactic medium. Future studies should consider these losses to understand the total contribution from NS mergers to the Universe's r-process budget.

Keywords: Neutron stars, Galaxies, Gamma-ray bursts, R-process, Early-type galaxies
High-energy Jet Emission from GRS 1758–258 and 1E 1740.7–2942 with INTEGRAL?. GRS 1758–258 and 1E 1740.7–2942 are two long-known persistent black hole binaries in the Galactic center region. Using the International Gamma-Ray Astrophysics Laboratory (INTEGRAL)'s extensive monitoring of the Galactic center and bulge, we studied their temporal and spectral evolutions in the 30–610 keV energy range from 2003 March through 2022 April with the Imager on Board INTEGRAL/INTEGRAL Soft Gamma-ray Imager gamma-ray telescope. Our analyses found that the sources typically had Comptonized spectra, though not always with the same parameters. The spectral states with more than 8 Ms of observation time show deviations from a Comptonized spectrum above ∼200 keV or a "hard tail" that extends up to at least 600 keV. The origin of this component remains debated, with the most popular scenarios being synchrotron emission from the jet or Comptonization in a hybrid thermal/nonthermal plasma. Anyway, the GRS 1758–258 and 1E 1740.7–2942 spectra are acceptably described by CompTT+po (jet) and Eqpair (hybrid Comptonization) scenarios. To differentiate between the two scenarios, we calculated the Spearman correlation coefficient comparing 30–50 keV count rates with those in higher energy bands (50–100, 100–300, and 300–600 keV). The count rates below 300 keV are strongly correlated, indicating those photons arise from the same physical process. Above 300 keV the count rates are either anticorrelated or not correlated with the 30–50 keV count rates for GRS 1758–258, which suggests that the photons originate from a different physical process. For 1E 1740.7–2942, the level of correlation is unclear due to scatter in the data points. However, the 300–600 keV count rates are consistent with a constant value. This disfavors the hybrid Comptonization scenario for both sources.

Keywords: Low-mass x-ray binary stars, Gamma-ray astronomy
Improved Constraints on the Faraday Rotation toward Eight Fast Radio Bursts Using Dense Grids of Polarized Radio Galaxies. We present 2–4 GHz observations of polarized radio galaxies toward eight fast radio bursts (FRBs), producing grids of Faraday rotation measure (RM) sources with sky densities of 9–28 polarized sources per square degree. Using a Bayesian interpolation framework, we constrain Galactic RM fluctuations below ∼1 deg2 angular scales around the FRB positions. Despite the positions of all eight FRBs being located far from the Galactic plane, we constrain previously unresolved small-scale Galactic RM structures around six of the eight FRBs. In two of these fields, we find potential changes in the sign of the Galactic RM that are not captured by previous, sparsely sampled RM grid observations. Our Galactic RM estimate toward the FRBs differs by a few radians per square meter up to ∼40 rad m‑2 from the all-sky Galactic RM map of S. Hutschenreuter et al. Extrapolating our results to the known population of polarized FRB sources, we may be incorrectly interpreting the host galaxy RM for ∼30% of the FRB source population with current RM grid observations. Measuring small-scale Galactic RM variations is crucial for identifying FRBs in low-density and weakly magnetized environments, which in turn could serve as potent probes of cosmic magnetism. This framework of reconstructing continuous Galactic RM structure from RM grid observations can be readily applied to FRBs that fall within the sky coverage of upcoming large-sky radio polarization surveys of radio galaxies, such as the Very Large Array Sky Survey and the Polarization Sky Survey of the Universe's Magnetism.

Keywords: Radio bursts, Polarimetry, Milky Way magnetic fields
Formation of Jet-driven Forced Reconnection Region and Associated Plasma Blobs in a Prominence Segment. We use data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory to study the most likely formation of a forced reconnection region and associated plasma blobs, triggered by jetlike structures in a prominence segment. Around 05:44 UT on 2017 December 16th, hot jetlike structures lifted from a nearby active region and fell obliquely on one side of the prominence segment with velocities of ≈45–65 km s‑1. These eruptions compressed the boundaries of the prominence and flux rope, forming an elongated reconnection region with inflow velocities of 47–52 km s‑1 and 36–49 km s‑1 in the projected plane. A thin, elongated reconnection region was formed, with multiple magnetic plasma blobs propagating bidirectionally at velocities of 91–178 km s‑1. These dense blobs, associated with ongoing reconnection, may also be linked to the onset of Kelvin–Helmholtz (K-H) instability. The blobs are attributed to plasmoids, moving at slower speeds (91–178 km s‑1) due to the high density in the prominence segment. The dimensionless reconnection rate varied from 0.57–0.28, 0.53–0.26, and 0.41–0.20, indicating reconnection rate enhancement and supporting the forced reconnection scenario. After reconnection, the prominence plasma heated to 6 MK, releasing significant thermal energy (≈5.4 × 1027 erg), which drained cool prominence plasma and heated it to coronal temperatures. The ubiquity of jets and outflows in the solar atmosphere makes the aforementioned reconnection and possible coexistence of K-H instability potentially important for the magnetic energy release and heating in the solar atmosphere.

Keywords: Solar magnetic fields, Solar physics, Solar prominences, Solar magnetic reconnection
The Redshift Evolution of the Luminosity Function of Type II Gamma-Ray Bursts. As of 2023 December, the Neil Gehrels Swift Observatory satellite has detected more than 1600 gamma-ray bursts (GRBs). We select 307 Type II GRBs for constructing the luminosity function (LF) based on the following criteria: (1) duration T90 ≥ 2 s; (2) conformity with the Amati relation for Type II GRBs; and (3) peak flux P ≥ 1 photon cm‑2 s‑1. We explore two general forms of the GRB LF: a broken power-law (BPL) LF and a triple power-law (TPL) LF. We consider three evolutionary scenarios: no evolution, luminosity evolution, and density evolution. We find that the no-evolution model can be excluded, while both the luminosity and density evolution models effectively account for the observations. This result is consistent with previous studies on long-duration GRBs (LGRBs). However, our Type II GRB sample favors a BPL LF, in contrast to the preference for a TPL function discovered for LGRBs.

Keywords: Luminosity function, Gamma-ray bursts, Star formation
CORINOS. III. Outflow Shocked Regions of the Low-mass Protostellar Source IRAS 15398–3359 with JWST and ALMA. While molecular outflows have been studied in detail with radio interferometry, observations of the hotter gas in protostellar outflows at a comparable physical scale are often challenging. Combined with the Atacama Large Millimeter/submillimeter Array (ALMA), JWST allows us to investigate the cold and hot gas with unprecedented spatial resolution and sensitivity. We present a detailed comparison between the gas distributions probed with ALMA and JWST in the primary outflow of IRAS 15398‑3359. At 2000 au scale, the southwestern outflow shows four shell structures in 5–10 μm continuum, whereas the submillimeter H2CO emission traces two of the four shells closest to the protostar. Submillimeter emission from CS, CCH, c–C3H2, and CH3OH shows the same two shells, and the 12CO emission covers most of the outflow region. SO and SiO only trace a condensation at the edge of the shell closest to the protostar. None of these lines observed with ALMA show the outermost shell. At 500 au scale, we find hot H2 gas inside the outflow cavity with JWST. The derived temperature of H2 is 1147 ± 198 K within a 0 5 aperture at the protostar. The foreground mass column density of dust is (1.4–2.0) × 10‑3 g · cm‑2 (AV = 47–66 mag) in the outflow, using the dust model from J. C. Weingartner &amp; B. T. Draine (2001). We also find an 8∘ difference between the directions toward the [Fe II] knot and the outermost shell in the MIRI image, which may be interpreted as the precession of the [Fe II] jet. The dynamical timescale of the [Fe II] knot is 10 yr, suggesting a current event.

Keywords: Stellar jets, Astrochemistry, James Webb Space Telescope, Star formation, Protostars
AT2021aeuk: A Repeating Partial Tidal Disruption Event Candidate in a Narrow-line Seyfert 1 Galaxy. A black hole (BH) can tear apart a star that ventures within its tidal radius, producing a luminous flare as the stellar debris falls back, known as a tidal disruption event (TDE). While TDEs in quiescent galaxies are relatively well understood, identifying TDEs in active galactic nuclei (AGNs) still remains a significant challenge. We present the discovery of AT2021aeuk, a transient exhibiting dual flares within around 3 yr in a narrow-line Seyfert 1 galaxy. Multiwavelength observations triggered during the second flare in 2023 revealed an extraordinary X-ray V-shaped light curve, strongly anticorrelated with the optical light curve and accompanied by a lag of ∼40 days. This behavior is inconsistent with both supernova and pure AGN origins. In addition, a new broad component emerges in the Balmer lines during the second flare, showing a clear reverberation signal to the continuum variation. We propose that the dual flare may be linked to a repeating partial TDE (rpTDE), where the second flare results from a collision between the TDE stream and the inner accretion disk, triggering an optical flare while simultaneously partially destroying the X-ray corona. However, other mechanisms, such as a stellar-mass BH merger within an accretion disk, could produce similar phenomena, which we cannot entirely rule out. The Vera C. Rubin Observatory will be a powerful tool for further investigating the nature of such events in the future.

Keywords: Tidal disruption, Active galactic nuclei, Transient detection
FEASTS Combined with Interferometry. III. The Low Column Density H I Around M51 and Possibility of Turbulent-mixing Gas Accretion. With a new joint-deconvolution pipeline, we combine the single-dish and interferometric atomic hydrogen (H I) data of M51 observed by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) (FEASTS program) and the Very Large Array (VLA) (THINGS). The product data cube has a typical line width of 13 km s‑1 and a 2σ line-of-sight (LOS) sensitivity of H I column density NH I ∼ 3.2 × 18 cm‑2 at a spatial resolution of ∼18″ (∼0.7 kpc). Among the H I detected LOSs extending to ∼50 kpc, ∼89% consist of diffuse H I only, which is missed by previous VLA observations. The distribution of dense H I is reproduced by previous hydrodynamical simulations of this system, but the diffuse component is not, likely due to unresolved physics related to the interaction between the circumgalactic and interstellar media. With simple models, we find that these low NH I structures could survive the background ultraviolet photoionization, but are susceptible to the thermal evaporation. We find a positive correlation between LOS velocity dispersion (σv) and NH I with a logarithmic index of ∼0.5. Based on existing turbulent mixing layer (TML) theories and simulations, we propose a scenario of hot gas cooling and accreting onto the disk through a TML, which could reproduce the observed power index of ∼0.5. We estimate the related cooling and accretion rates to be roughly one-third to two-thirds of the star formation rate. A typical column density of diffuse H I (∼1019 cm‑2) can be accreted within 300 Myr, the interaction timescale previously estimated for the system. Such a gas accretion channel has been overlooked before, and may be important for gas-rich interacting systems and for high-redshift galaxy evolution.

Keywords: Interstellar atomic gas, Deconvolution, Atomic interferometry, Single-dish antennas, Galaxy mergers, Galaxy accretion, Circumgalactic medium
Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission. Using data collected by the Indian Mars Orbiter Mission (MOM) in 2021 October, we investigated coronal regions of the Sun by analyzing the Doppler spectral width of radio signals to estimate solar wind velocity. A simplified equation is introduced to directly relate these two parameters. The study focuses on observations conducted from 2021 October 2 to October 14, a relatively quiet phase of solar cycle 25. The analysis targeted the coronal region within heliocentric distances of 5–8 R⊙, near the ecliptic plane. In this region, solar wind velocities ranged from 100 to 150 km s‑1, while electron densities were on the order of 1010 m‑3. We also compared our results with electron density observations and models derived from previous studies. Though the decrease in the electron densities with respect to increasing heliocentric distance matches quite well with the theoretical models, MOM estimates fall at the lower edge of the distribution. This difference may be attributed to the prolonged weak solar activity during the MOM observations, in contrast to prior studies conducted during periods of comparatively higher solar activity in earlier solar cycles.

Keywords: Solar wind, Radio occultation, Solar corona
Accelerated Emergence of Evolved Galaxies in Early Overdensities at z ∼ 5.7. We report the identification of two galaxy overdensities at z ∼ 5.7 in the sightline of the galaxy cluster A2744. These overdensities consist of 25 and 17 member galaxies, spectroscopically confirmed with JWST NIRSpec micro-shutter assembly and NIRCam/WFSS. Each overdensity has a total stellar mass of ∼2 × 1010 M⊙ and a star formation rate of ∼200 M⊙ yr‑1 within a central region of radius R = 2 Mpc (physical). The sensitive PRISM spectra allow us to identify six galaxies that show weak Hα + [N II] emissions within the overdensities (25% ± 7%), whereas the fraction of such galaxies is found significantly lower (6% ± 2%) in field samples of the equivalent redshift range. These weak emission line galaxies, dubbed as wELGs, exhibit a strong continuum break at the 4000 Å rest frame, a characteristic feature of evolved stellar populations. The high observed fraction of wELGs in the two overdensities is consistent with the idea that high-density environments are an ideal site where galaxies can accelerate their evolutionary pace compared to field analogs. Our study pinpoints an early onset of environmental effects, already important within one billion years after the Big Bang, and provides a complementary perspective on the emergence of quenched, massive galaxies at lower redshifts. Potential contributions from black hole accretion feedback to the reduction in star formation activity are discussed, but the connection to the local environments remains unclear.

Keywords: Interstellar medium, Emission line galaxies, High-redshift galaxy clusters