Sazuna/UAT_keywords huggingface dataset:
Rapid Rotation of Polarization Orientations in PSR B1919+21's Single Pulses: Implications on Pulsar's Magnetospheric Dynamics. We analyze and model rapid rotations of polarization orientations in PSR B1919+21's single pulses based on Five-hundred-meter Aperture Spherical radio Telescope observation data. In more than one-third of B1919+21's single pulses, the polarization position angle (PA) is found to rotate quasi-monotonically with pulse longitude over 180° or even 360°. Some single pulse PA even rotates by over 540°. Most of these quasi-monotonic PA curves have negative slopes with respect to pulse longitude. Oscillations of circular polarization fraction accompany these PA rotations. This rapid rotation could be induced by a quick change of phase lag between two normal wave modes within an individual pulse. We propose a phenomenological model to reproduce the observed polarization rotations in single pulses, and calculate phase lags in a dipolar magnetic field of an aligned rotating pulsar, with a dispersion relation of orthogonal wave modes in strongly magnetized electron-positron plasma. According to the dispersion relation, the weak frequency dependence of observed polarization rotation requires small angles between the radio wavevector and local magnetic fields, which requires the radio emission height to be low, on the order of 10 times neutron star radius.

Keywords: Neutron stars, Magnetospheric radio emissions, Plasma astrophysics, Radiative processes, Polarimetry, Radio pulsars
Radio Pulse Search from Aql X-1. We present 12 observations of the accreting millisecond X-ray pulsar Aql X-1, taken from 2022 August to 2023 October using the Five-hundred-meter Aperture Spherical Radio Telescope at 1250 MHz. These observations covered both the quiescence and X-ray outburst states, as determined by analyzing the X-ray data from the Neutron Star Interior Composition Explorer and the Monitor of All-sky X-ray Image. Periodicity and single-pulse searches were conducted for each observation, but no pulsed signals were detected. The obtained upper limit flux densities are in the range of 2.86‑5.73 μJy, which provide the lowest limits to date. We discuss several mechanisms that may prevent detection, suggesting that Aql X-1 may be in the radio-ejection state during quiescence, where the radio pulsed emissions are absorbed by the matter surrounding the system.

Keywords: Millisecond pulsars, Radio pulsars
Seoul National University AGN Monitoring Project. V. Velocity-resolved Hβ Reverberation Mapping and Evidence of Kinematics Evolution. We present velocity-resolved reverberation lags of Hβ for 20 active galactic nuclei (AGNs) from the Seoul National University AGN Monitoring Project. We detect unambiguous velocity-resolved structures in 12 AGNs, among which eight objects exhibit symmetric structures, two objects show inflow-like characteristics, and two objects display outflow-like signatures. For two AGNs, we successfully measure the velocity-resolved lags in different years, revealing evidence of evolving broad-line region (BLR) kinematics. By combining our sample with the literature velocity-resolved lags, we find that the symmetric velocity-resolved lags are the most common (40%) type among this sample. The frequency of inflow kinematics is also notable (20%), while outflow kinematics are less common (11%). Our sample significantly expands the previous velocity-resolved reverberation mapping sample in the high-luminosity regime, enabling us to constrain BLR kinematics across a large dynamic range of luminosity.

Keywords: Reverberation mapping, Active galactic nuclei, Quasars
Constraining Baryonic Feedback Effects on the Matter Power Spectrum with Fast Radio Bursts. In the age of large-scale galaxy and lensing surveys, such as DESI, Euclid, Roman, and Rubin, we stand poised to usher in a transformative new phase of data-driven cosmology. To fully harness the capabilities of these surveys, it is critical to constrain the poorly understood influence of baryon feedback physics on the matter power spectrum. We investigate the use of a powerful and novel cosmological probe, fast radio bursts (FRBs), to capture baryonic effects on the matter power spectrum, leveraging simulations from the Cosmology and Astrophysics with MachinE Learning Simulations (or CAMELS) project, including IllustrisTNG, SIMBA, and Astrid. We find that FRB statistics exhibit a strong correlation, independent of the subgrid model and cosmology, with quantities known to encapsulate baryonic impacts on the matter power spectrum, such as baryon spread and the halo baryon fraction. We propose an innovative method utilizing FRB observations to quantify the effects of feedback physics and enhance weak-lensing measurements of S8. We outline the necessary steps to prepare for the imminent detection of large FRB populations in the coming years, focusing on understanding the redshift evolution of FRB observables and mitigating the effects of cosmic variance.

Keywords: Cosmology, Radio transient sources
The Massive and Distant Clusters of WISE Survey. XII. Exploring X-Ray Active Galactic Nuclei in Dynamically Active Massive Galaxy Clusters at z ∼ 1. We present an analysis of the cluster X-ray morphology and active galactic nucleus (AGN) activity in nine z ∼ 1 galaxy clusters from the Massive and Distant Clusters of WISE Survey observed with Chandra. Using photon asymmetry (Aphot) to quantify X-ray morphologies, we find evidence that the four most dynamically disturbed clusters are likely to be mergers. Employing a luminosity cut of 7.6 × 1042 erg s−1 to identify AGNs in the 0.7─7.0 keV region, we show that the majority of these clusters host excess AGNs compared to the local field. We use the model of cumulative number counts ( ) to predict AGN incidence in cluster isophotes under this luminosity cut. Our analysis finds evidence (at &gt;2σ) of a positive correlation between AGN surface densities and photon asymmetry, suggesting that a disturbed cluster environment plays a pivotal role in regulating triggering of AGNs. Studying AGN incidence in cluster X-ray isophotes equivalent in area to 1.0r500, we find that the AGN space density inversely scales with cluster mass as   at the 3.18σ level. Finally, when we separately explore the cluster mass dependence of excess AGN surface density in disturbed and relaxed clusters, we see tentative evidence that the two morphologically distinct subpopulations exhibit diverging trends, especially near the outskirts, likely due to cluster merger-driven AGN triggering/suppression.

Keywords: Galaxy clusters, X-ray astronomy, High-redshift galaxy clusters, Galaxy environments, X-ray active galactic nuclei, Intracluster medium
The Birth of a Major Coronal Mass Ejection with Intricate Magnetic Structure from Multiple Active Regions. Coronal mass ejections (CMEs) are the eruptions of magnetized plasma from the Sun and are considered the main driver of adverse space weather events. Hence, understanding their formation process, particularly the magnetic topology, is critical for accurate space weather prediction. Here, based on imaging observations and three-dimensional (3D) data-constrained thermodynamic magnetohydrodynamic (MHD) simulation in spherical coordinates, we exhibit the birth of a CME with intricate magnetic structure from multiple active regions (ARs) due to 3D magnetic reconnection. It is observed as a coronal jet between ARs, accompanied by the back-flowing of filament materials along the jet spine after the passage of the eruptive filament. This jet connects two dimming regions within different ARs. This is an observational proxy of 3D magnetic reconnection between the CME flux rope and the null-point magnetic field lines crossing ARs. Hereafter, the thermodynamic data-constrained MHD simulation successfully reproduces the observed jet and the reconnection process that flux ropes partake in, leading to a CME flux rope with a complex magnetic structure distinct from its progenitor. The generality of this scenario is then validated by data-inspired MHD simulations in a simple multipolar magnetic configuration. This work demonstrates the role of multiple ARs in forming CMEs with intricate magnetic structures. On the one hand, a noncoherent flux rope where not all twisted magnetic field lines wind around one common axis is naturally formed. On the other hand, our findings suggest that the topology of a real CME flux rope may not be solely determined by a single AR, particularly during periods of solar maximum.

Keywords: Solar magnetic fields, Solar coronal mass ejections, Magnetohydrodynamical simulations
Core Revelations: The Star Formation and Active Galactic Nucleus Connection at the Heart of NGC 7469. We investigate the star formation─active galactic nucleus (AGN) connection in the Seyfert 1 NGC 7469 using James Webb Space Telescope mid-infrared spectroscopic integral field unit (IFU) data. We use the IFU data to generate maps of different emission lines present in the spectrum, such as the star formation (SF) tracer [Ne II] 12.81 μm and the AGN tracer [Ne V] 14.32 μm. We can separate the AGN- and SF-dominated regions using spatially resolved mid-infrared diagnostic diagrams, and we further investigate the ionization sources powering each region by constructing photoionization models. We find that the previously detected eastern wind populates an intermediary region of the diagrams, between our star-forming and AGN points. Although it is possible that the star-forming ring may inherently not be uniform, this wind also coincides with a reduction in the [Ne II] emission in the ring, which suggests that the ionization cone intersects the ring in this direction.

Keywords: Starburst galaxies, Active galaxies, Ultraluminous infrared galaxies, Infrared galaxies
Constraints on Dark Matter Self-interactions from Weak Lensing of Galaxies from the Dark Energy Survey around Clusters from the Atacama Cosmology Telescope Survey. Self-interactions of dark matter particles impact the distribution of dark matter in halos. The exact nature of the self-interactions can lead to either expansion or collapse of the core within the halo lifetime, leaving distinctive signatures in the dark matter distributions not only at the halo center but throughout the virial region. Optical galaxy surveys, which precisely measure the weak lensing of background galaxies by massive foreground clusters, allow us to directly measure the matter distribution within clusters and probe subtle effects of self-interacting dark matter (SIDM) throughout the halo's full radial range. We compare the weak-lensing measurements reported by T. Shin et al., which use lens clusters identified by the Atacama Cosmology Telescope Survey and source galaxies from the Dark Energy Survey, with predictions from SIDM models having either elastic or dissipative self-interactions. To model the weak-lensing observables, we use cosmological N-body simulations for elastic self-interactions and semianalytical fluid simulations for dissipative self-interactions. We find that current weak-lensing measurements already constrain the isotropic and elastic SIDM to a cross section per mass of σ/m &lt; 1 cm2 g‑1 at a 95% confidence level for clusters with mean M200m = 3 × 1014 M⊙ h–1. The same measurements also impose novel constraints on the energy loss per unit mass for dissipative SIDM. Upcoming surveys are anticipated to enhance the signal-to-noise ratio of weak-lensing observables significantly, making them effective tools for investigating the nature of dark matter, including self-interactions, through weak lensing.

Keywords: Weak gravitational lensing, Galaxy dark matter halos, Dark matter, Particle physics
The Vertical Metallicity Gradient of the Galactic Disk for Mono-age Stellar Populations in LAMOST. The vertical metallicity gradient of the Galactic disk offers valuable insights into the disk's formation and chemical evolution over time. We utilized the Large Sky Area Multi-Object Fibre Spectroscopic Telescope low-resolution spectral young stellar sample to investigate this gradient and found that it approaches zero as stellar effective temperature (or age) increases (or decreases) across various Galactocentric distances. To validate this result, we analyzed 295 open clusters younger than 3 Gyr and 976 classical cepheids within the Galactic disk. The findings confirmed that, within a given narrow age range, the vertical metallicity gradient is effectively zero. This relationship between metallicity and age supports the "upside-down" disk formation theory, as it indicates that the youngest and most metal-rich stars dominate the midplane, while older and more metal-poor stars formed at larger vertical heights and currently tend to be at these heights. Overall, our results align well with theoretical predictions, offering further insight into the chemical evolution and structural properties of the Milky Way.

Keywords: Galaxy formation, Galaxy structure, Galaxy disks, Galaxy abundances, Galaxy evolution, Metallicity
The Infrared Traced Star Formation Rates of Associated Absorption Lines Quasars. Some optically selected quasars exhibit Mg II-associated absorption lines (AALs), and their origin remains unclear. In this paper, we compile a sample of 1769 quasars, with or without Mg II AALs, of which 1689 are far-infrared (FIR) detected quasars and the rest are not detected in FIR. For the FIR undetected quasars, we obtain stacks for both with and without Mg II AAL quasars. Then, we estimate the star formation rates (SFRs) within quasar host galaxies based on their FIR luminosities derived from their FIR graybody components, and find that, although quasars with Mg II AALs have significantly redder median composite spectra than those without Mg II AALs, the SFR distributions of the two types of quasars are statistically indistinguishable. These results do not require an evolutionary link between the quasars with and without Mg II AALs, and would be reconciled if an orientation effect cannot be ignored among the quasars hosting different types of absorption lines.

Keywords: Active galaxies
Detection of the Optical Counterpart of the Transient ULX NGC 300 ULX-1: A Nascent Black Hole-neutron Star Binary?. The endpoints of massive star evolution are poorly known, especially those in interacting binary systems containing compact objects, such as neutron stars or black holes (BHs). Such systems are bright in X-rays, and the most luminous among them are called ultra-luminous X-ray sources (ULXs). In this paper, we address the enigmatic NGC 300 ULX-1. Its X-ray activity started in 2010 with the supernova impostor-like event SN 2010da. In the following few years, the ULX was powered by persistent super-Eddington accretion but then it dimmed in X-rays. We present the most recent X-ray and optical observations. The Chandra and Swift telescopes confirm that SN 2010da/NGC 300 ULX-1 is not accreting at the super-Eddington level anymore. We attribute this switch in accretion regime to the donor star variability and its fast evolution. In order to gain a better understanding of the donor star's nature, we consider its optical light curve on a decade-long timescale and show that the optical counterpart of SN 2010da/NGC 300 ULX-1 dimmed significantly over recent years. The most recent detection in the optical by the Gemini telescope reveals that the source is now &gt;2.5 mag fainter in the   band compared to the epoch when it was spectroscopically classified as a red supergiant. We discuss the nature of the abrupt changes in the donor star properties and consider, among other possibilities, the silent collapse of the donor star into a BH.

Keywords: Ultraluminous x-ray sources, High mass x-ray binary stars, Multiple star evolution, Core-collapse supernovae
The Relative Constraining Power of the High-z 21 cm Dipole and Monopole Signals. The 21 cm background is a promising probe of early star formation and black hole activity. While a slew of experiments on the ground seek to detect the 21 cm monopole and spatial fluctuations on large ∼10' scales, little work has been done on the prospects for detecting the 21 cm dipole signal or its utility as a probe of early galaxies. Though an intrinsically weak signal relative to the monopole, its direction is known well from the cosmic microwave background and wide-field surveys; furthermore, as a relative measurement the dipole could help relax instrumental requirements. In order to understand the constraining power of the dipole, in this work we perform parameter inference on mock data sets that include the dipole, the monopole, or both signals. We find that while the monopole does provide the best constraints for a given integration time, constraints from a dipole measurement are competitive and can in principle constrain the cosmic star formation rate density and efficiency of X-ray photon production in early z ∼ 15 galaxies to better than a factor of ∼2. This result holds for most of the available prior volume, which is set by constraints on galaxy luminosity functions, the reionization history, and upper limits from 21 cm power spectrum experiments. We also find that predictions for the monopole from a dipole measurement are robust to different choices of signal model. As a result, the 21 cm dipole signal is a valuable target for future observations and offers a robust cross-check on monopole measurements.

Keywords: Galaxy formation, Diffuse radiation, Intergalactic medium, Reionization, High-redshift galaxies
JWST Spectroscopic View of a Rapidly Growing, Dust-obscured Quasar at z ∼ 4: Effect of Dust Extinction Correction on Black Hole Mass and Eddington Ratio Estimation. In the merger-driven galaxy evolution scenario, the central supermassive black holes (SMBHs) in dust-obscured galaxies grow rapidly. Interestingly, a recent work on a dust-obscured galaxy, LID-568 at z = 3.965, has shown that its SMBH is growing extremely fast at about 40 times the Eddington-limited accretion rate (i.e., super-Eddington accretion). However, the heavy dust extinction of the host galaxy could affect the result if not corrected properly. Here, we analyze James Webb Space Telescope (JWST) NIRSpec integral field unit (IFU) and MIRI spectra of LID-568. By measuring its bolometric luminosity (Lbol) and black hole (BH) mass (MBH) using an extinction-free estimator based on mid-infrared spectra, we obtain Lbol = 1046.83±0.07 erg s‑1 and MBH = 108.43±0.15 M⊙. The measured Eddington ratio (λEdd) is 1.97 ± 0.88, consistent with the accretion rate at the Eddington limit; in other words, it is not super-Eddington in a significant manner. This result underscores challenges and the importance of carefully considering dust extinction when analyzing the BH growth in dust-obscured quasars.

Keywords: Early universe, Supermassive black holes, Quasars, Infrared astronomy, James Webb Space Telescope, Galaxy evolution
A Population Synthesis Study on the Formation of Cold Jupiters from Truncated Planetesimal Disks. The occurrence rate of giant planets increases with orbital period and turns over at a location that roughly corresponds to the snowline of solar-type stars. Further, the density distribution of cold Jupiters (CJs) on the semimajor axis–mass diagram shows a relatively steep inner boundary, shaping the desert of warm Jupiters. The eccentricities of CJs show a broad distribution with a decreasing number density toward the larger end. Previous planet formation models fail to reproduce all these features at the same time. We use a planet population synthesis (PPS) model with truncated initial planetesimal distribution and compare the mass and orbital distribution of the simulated planets with the observation. We show that the occurrence of CJs with respect to the orbital period, the slope of the inner boundary of CJs on the semimajor axis–mass diagram, and the eccentricity distribution of CJs agree reasonably well with observations, if CJs form from truncated planetesimal disks of 10 au or wider with suppressed migration. While PPS simulations generally overestimate the fraction of giants with eccentricity below 0.2, N-body simulations produce a more consistent eccentricity distribution with observations. While the fraction of high-eccentricity planets can be increased by widening the planetesimal disk or reducing the migration speed, a deficit of giants with eccentricity between 0.2 and 0.4 exists regardless of the choices of parameters. Our results indicate that CJs are more likely born in truncated disks near the snowline than in classical uniform disks.

Keywords: Extrasolar gaseous planets, N-body simulations, Planet formation
The Impacts of Bars, Spirals, and Bulge Size on Gas-phase Metallicity Gradients in MaNGA Galaxies. As galaxies evolve over time, the orbits of their constituent stars are expected to change in size and shape, moving stars away from their birth radius. Radial gas flows are also expected. Spiral arms and bars in galaxies are predicted to help drive this radial relocation, and it may be possible to trace this observationally, via a flattening of metallicity gradients. We use data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, part of the fourth phase of the Sloan Digital Sky Surveys (SDSS-IV), to look for correlations of the steepness of gas-phase metallicity gradients with various galaxy morphological features (e.g., the presence and pitch angle of spiral arms, the presence of a large scale bar, and bulge size). We select from MaNGA a sample of star-forming galaxies for which gas-phase metallicity trends can be measured and we use morphologies from the Galaxy Zoo survey. We observe that at fixed galaxy mass (1) the presence of spiral structure correlates with steeper gas-phase metallicity gradients; (2) spiral galaxies with larger bulges have both higher gas-phase metallicities and shallower gradients; (3) there is no observable difference in azimuthally averaged radial gradients between barred and unbarred spirals; and (4) there is no observable difference in gradient between tight and loosely wound spirals, but looser-wound spirals have lower average gas-phase metallicity values at fixed mass. We discuss the possible implications of these observational results.

Keywords: Interstellar medium, Metallicity, Galaxy evolution, Spiral galaxies
Exploring the Origin of Solar Energetic Electrons. II. Investigating Turbulent Coronal Acceleration. Nonthermal particle acceleration in the solar corona is evident from both remote hard X-ray sources in the chromosphere and direct in situ detection in the heliosphere. Correlation of spectral indices between remote and in situ energy spectra presents the possibility of a common source-acceleration region within the corona, however the properties and location of this region are not well constrained. To investigate this, we perform a parameter study for both the properties of the ambient plasma of a simulated acceleration region and the turbulent acceleration profile acting on an initially isotropic thermal electron population. We find that independently varying the turbulent acceleration timescale τacc, acceleration profile standard deviation σ, and acceleration region length L result in an in situ spectral index variation of between 0.5 and 2.0 at 1.0 au for &lt;100 keV electrons. Short-timescale turbulent scattering in the flaring corona steepens the spectra by ~0.5. It was also found that the in situ spectral index δ derived from the peak electron flux produces a spectral index ~1.6 harder than that from a full-flare X-ray photon flux (of spectral index γ) simulated with the same intermediate parameters. Previous studies have indicated an approximate δ ≈ γ relationship for selected flares with measured in situ electron and X-ray photon observations, suggesting that an extended source region with nonuniform plasma and/or acceleration properties may be necessary to reproduce this relationship.

Keywords: Solar energetic particles, Active solar corona, Solar flares, Heliosphere