Sazuna/UAT_keywords huggingface dataset:
Early Planet Formation in Embedded Disks (eDisk). XV. Influence of Magnetic Field Morphology in Dense Cores on Sizes of Protostellar Disks. The magnetic field of a molecular cloud core may play a role in the formation of circumstellar disks in the core. We present magnetic field morphologies in protostellar cores of 16 targets in the Atacama Large Millimeter/submillimeter Array large program "Early Planet Formation in Embedded Disks (eDisk)," which resolved their disks with 7 au resolutions. The 0.1 pc scale magnetic field morphologies were inferred from the James Clerk Maxwell Telescope POL-2 observations. The mean orientations and angular dispersions of the magnetic fields in the dense cores are measured and compared with the radii of the 1.3 mm continuum disks and the dynamically determined protostellar masses from the eDisk program. We observe a significant correlation between the disk radii and the stellar masses. We do not find any statistically significant dependence of the disk radii on the projected misalignment angles between the rotational axes of the disks and the magnetic fields in the dense cores, nor on the angular dispersions of the magnetic fields within these cores. However, when considering the projection effect, we cannot rule out a positive correlation between disk radii and misalignment angles in three-dimensional space. Our results suggest that the morphologies of magnetic fields in dense cores do not play a dominant role in the disk formation process. Instead, the sizes of protostellar disks may be more strongly affected by the amount of mass that has been accreted onto star+disk systems, and possibly other parameters, for example, magnetic field strength, core rotation, and magnetic diffusivity.

Keywords: Star forming regions, Interstellar magnetic fields, Star formation, Circumstellar disks, Protostars
Multiband Simultaneous Photometry of Type II SN 2023ixf with Mephisto and the Twin 50 cm Telescopes. SN 2023ixf, recently reported in the nearby galaxy M101 at a distance of 6.85 Mpc, was one of the closest and brightest core-collapse supernovae in the last decade. In this work, we present multiwavelength photometric observation of SN 2023ixf with the Multi-channel Photometric Survey Telescope (Mephisto) in the uvgr bands and with the twin 50 cm telescopes in the griz bands. We find that the bolometric luminosity reached the maximum value of 3 × 1043 erg s‑1 at 3.9 days after the explosion and fully settled onto the radioactive tail at ∼90 days. The effective temperature decreased from 3.2 × 104 K at the first observation and approached a constant of ∼(3000–4000) K after the first 2 months. The evolution of the photospheric radius is consistent with a homologous expansion with a velocity of 8700 km s‑1 in the first 2 months, and it shrunk subsequently. Based on the radioactive tail, the initial nickel mass is about M Ni ∼ 0.098 M ⊙. The explosion energy and the ejecta mass are estimated to be E ≃ (1.0–5.7) × 1051 erg and M ej ≃ (3.8–16) M ⊙, respectively. The peak bolometric luminosity is proposed to be contributed by the interaction between the ejecta and the circumstellar medium (CSM). We find a shocked CSM mass of M CSM ∼ 0.013 M ⊙, a CSM density of ρ CSM ∼ 2.5 × 10‑13 g cm‑3, and a mass-loss rate of the progenitor of  Ṁ∼0.022M⊙yr‑1 .

Keywords: Type II supernovae, Circumstellar matter, Core-collapse supernovae, Stellar mass loss
GRB 231115A: A Nearby Magnetar Giant Flare or a Cosmic Short Gamma-Ray Burst?. There are two classes of gamma-ray transients with a duration shorter than 2 s. One consists of cosmic short gamma-ray bursts (GRBs) taking place in the deep Universe via the neutron star mergers, and the other is the magnetar giant flares (GFs) with energies of ∼1044 − 1046 erg from "nearby" galaxies. Though the magnetar GFs and the short GRBs have rather similar temporal and spectral properties, their energies (E  γ,iso) are different by quite a few orders of magnitude and hence can be distinguished supposing the host galaxies have been robustly identified. The newly observed GRB 231115A has been widely discussed as a new GF event for its high probability of being associated with M82. Here we conduct a detailed analysis of its prompt emission observed by Fermi-GBM and compare the parameters with existing observations. The prompt gamma-ray emission properties of GRB 231115A, if associated with M82, nicely follow the E p,z─E  γ,iso relation of the GFs, where E p,z is the peak energy of the gamma-ray spectrum after the redshift (z) correction. To be a short GRB, the redshift needs to be ∼1. Though such a chance is low, the available X-ray/GeV observation upper limits are not stringent enough to further rule out this possibility. We have also discussed the prospect of convincingly establishing the magnetar origin of GRB 231115A-like events in the future.

Keywords: Magnetars, Gamma-ray bursts
Chandra Study of the Proper Motion of HST-1 in the Jet of M87. The radio galaxy M87 is well known for its jet, which features a series of bright knots observable from radio to X-ray wavelengths. We analyze the X-ray image and flux variability of the knot HST-1 in the jet. Our analysis includes all 112 available Chandra ACIS-S observations from 2000 to 2021, with a total exposure time of ∼884 ks. We use deconvolved images to study the brightness profile of the X-ray jet and measure the relative separation between the core and HST-1. From 2003 to 2005 (which coincides with a bright flare from HST-1), we find a correlation between the flux of HST-1 and its offset from the core. In subsequent data, we find a steady increase in this offset, which implies a bulk superluminal motion for HST-1 of 6.6 ± 0.9 c (2.0 ± 0.3 pc yr‑1), in keeping with prior results. We discuss models for the flux–offset correlation that feature either two or four emission regions separated by tens of parsecs. We attribute these results to moving shocks in the jet, which allow us to measure the internal structure of the jet.

Keywords: X-ray astronomy, Shocks, Active galaxies, Relativistic jets
PAC. V. The Roles of Mass and Environment in the Quenching of Galaxies. The roles that mass and environment play in galaxy quenching are still under debate. Leveraging the Photometric objects Around Cosmic webs method, we analyze the excess surface distribution  n¯2wp(rp)  of photometric galaxies in different colors (rest-frame u ‑ r) within the stellar mass range of 109.0 ∼ 1011.0 M ⊙ around spectroscopic massive central galaxies (1010.9 ∼ 1011.7 M ⊙) at the redshift interval of 0 &lt; z  s  &lt; 0.7, utilizing data from the Hyper Suprime-Cam Subaru Strategic Program and the spectroscopic samples of Slogan Digital Sky Survey (i.e., Main, LOWZ, and CMASS samples). We find that both mass and environmental quenching contribute to the evolution of companion galaxies. To isolate the environmental effect, we quantify the quenched fraction excess (QFE) of companion galaxies encircling massive central galaxies within 0.01h ‑1 Mpc &lt; r p &lt; 20h ‑1 Mpc, representing the surplus quenched fraction relative to the average. We find that the high-density halo environment affects star formation quenching up to about three times the virial radius, and this effect becomes stronger at lower redshift. We also find that even after being scaled by the virial radius, the environmental quenching efficiency is higher for more massive halos or for companion galaxies of higher stellar mass, though the trends are quite weak. We present a fitting formula that comprehensively captures the QFE across central and companion stellar mass bins, halo-centric distance bins, and redshift bins, offering a valuable tool for constraining galaxy formation models. Furthermore, we have made a quantitative comparison with IllustrisTNG that underscores some important differences, particularly in the excessive quenching of low-mass companion galaxies (&lt;109.5 M ⊙) in the simulation.

Keywords: Galaxy quenching, Galaxy formation, Galaxy evolution
Streaming Instability and Turbulence: Conditions for Planetesimal Formation. The streaming instability (SI) is a leading candidate for planetesimal formation, which can concentrate solids through two-way aerodynamic interactions with the gas. The resulting concentrations can become sufficiently dense to collapse under particle self-gravity, forming planetesimals. Previous studies have carried out large parameter surveys to establish the critical particle to gas surface density ratio (Z), above which SI-induced concentration triggers planetesimal formation. The threshold Z depends on the dimensionless stopping time (τ  s , a proxy for dust size). However, these studies neglected both particle self-gravity and external turbulence. Here, we perform 3D stratified shearing box simulations with both particle self-gravity and turbulent forcing, which we characterize via a turbulent diffusion parameter, α D. We find that forced turbulence, at amplitudes plausibly present in some protoplanetary disks, can increase the threshold Z by up to an order of magnitude. For example, for τ  s  = 0.01, planetesimal formation occurs when Z ≳ 0.06, ≳0.1, and ≳0.2 at α D = 10‑4, 10‑3.5, and 10‑3, respectively. We provide a single fit to the critical Z required for the SI to work as a function of α D and τ  s  (although limited to the range τ  s  = 0.01–0.1). Our simulations also show that planetesimal formation requires a mid-plane particle-to-gas density ratio that exceeds unity, with the critical value being largely insensitive to α D. Finally, we provide an estimation of particle scale height that accounts for both particle feedback and external turbulence.

Keywords: Hydrodynamical simulations, Hydrodynamics, Protoplanetary disks, Planetesimals, Planet formation
Ensemble Variability Properties of Active Galactic Nuclei in the SDSS DR17. We present the results from a study of ∼9600 broadline-selected active galactic nuclei (AGNs) with host galaxies detected from the Sloan Digital Sky Survey (SDSS) Data Release 17. We compute ensemble variability statistics based on a comparison of the original SDSS photometric data with spectrophotometric measurements obtained days to decades later in the Sloan g, r, and i bands. Galaxy and AGN templates have been fitted to the SDSS spectra to isolate the AGN component from the host galaxy. The sources have absolute magnitudes in the range ‑24 &lt; M i  &lt; ‑18 and lie at redshifts less than z ∼ 0.9. A variability analysis reveals that the anticorrelation between luminosity and variability amplitude continues down to log(Lbol [erg s‑1]) = 43.5, demonstrating that the relationship extends by 4 orders of magnitude in AGN luminosity. To further explore the connection between AGN luminosity and variability, we determine the black hole mass and the accretion rate through measurement of the Hβ line width and the monochromatic luminosity at rest frame 5100 Å. Our results suggest that the accretion rate is the dominant parameter impacting the amplitude of variability and that the anticorrelation between the accretion rate and amplitude extends to rates as low as 1% Eddington. Moreover, we also identify an anticorrelation between the variability amplitude and black hole mass, with the correlation appearing strongest among the AGNs with low accretion rates.

Keywords: Supermassive black holes, Quasars, Principal component analysis, Multivariate analysis, Low-luminosity active galactic nuclei, Active galactic nuclei, Time domain astronomy, Seyfert galaxies, Extragalactic astronomy, Sloan photometry
Consistent Eccentricities for Gravitational-wave Astronomy: Resolving Discrepancies between Astrophysical Simulations and Waveform Models. Detecting imprints of orbital eccentricity in gravitational-wave (GW) signals promises to shed light on the formation mechanisms of binary black holes. To constrain the formation mechanisms, distributions of eccentricity derived from numerical simulations of astrophysical formation channels are compared to the estimates of eccentricity inferred from GW signals. We report that the definition of eccentricity typically used in astrophysical simulations is inconsistent with the one used while modeling GW signals, with the differences mainly arising due to the choice of reference frequency used in both cases. We also posit a prescription for calculating eccentricity from astrophysical simulations, by evolving ordinary differential equations obtained from post-Newtonian theory and using the dominant (ℓ = m = 2) mode's frequency as the reference frequency; this ensures consistency in the definitions. On comparing the existing eccentricities of the binaries present in the Cluster Monte Carlo catalog of globular cluster simulations with the eccentricities calculated using the prescription presented here, we find a significant discrepancy at e ≳ 0.2; this discrepancy becomes worse with increasing eccentricity. We note the implications this discrepancy has for existing studies and recommend that care be taken when comparing data-driven constraints on eccentricity to expectations from astrophysical formation channels.

Keywords: Gravitational wave astronomy, Gravitational wave sources
Breaking Giant Chains: Early-stage Instabilities in Long-period Giant Planet Systems. Orbital evolution is a critical process that sculpts planetary systems, particularly during their early stages where planet–disk interactions are expected to lead to the formation of resonant chains. Despite the theoretically expected prominence of such configurations, they are scarcely observed among long-period giant exoplanets. This disparity suggests an evolutionary sequence wherein giant planet systems originate in compact multiresonant configurations, but subsequently become unstable, eventually relaxing to wider orbits—a phenomenon mirrored in our own solar system's early history. In this work, we present a suite of N-body simulations that model the instability-driven evolution of giant planet systems, originating from resonant initial conditions, through phases of disk dispersal and beyond. By comparing the period ratio and normalized angular momentum distributions of our synthetic aggregate of systems with the observational census of long-period Jovian planets, we derive constraints on the expected rate of orbital migration, the efficiency of gas-driven eccentricity damping, and typical initial multiplicity. Our findings reveal a distinct inclination toward densely packed initial conditions, weak damping, and high giant planet multiplicities. Furthermore, our models indicate that resonant chain origins do not facilitate the formation of Hot Jupiters via the coplanar high-eccentricity pathway at rates high enough to explain their observed prevalence.

Keywords: Exoplanet dynamics, Exoplanet migration, Exoplanet astronomy, Planetary science, Exoplanet formation, Planetary dynamics, Dynamical evolution
Infrared Band Strengths of Dangling OH Features in Amorphous Water at 20 K. Infrared (IR) spectra of vapor-deposited amorphous water at low temperatures show two weak peaks at around 3720 and 3696 cm‑1 assigned to free-OH stretching modes of two- and three-coordinated water molecules (so-called "dangling" OH bonds), respectively, on the ice surface. A recent JWST observation first succeeded in detection of a potential dangling OH feature at 3664 cm‑1 for ices in molecular clouds, highlighting the importance of dangling OH bonds in interstellar ice chemistry. A lack of band strengths of these features at low temperatures restricts the quantification of dangling OH bonds from IR spectra, hindering development of a molecular-level understanding of the surface structure and chemistry of ice. Using IR multiple-angle incidence resolution spectrometry, we quantified the band strengths of two- and three-coordinated dangling OH features in amorphous water at 20 K as being 4.6 ± 1.6 × 10‑18 and 9.1 ± 1.0 × 10‑18 cm molecule‑1, respectively. These values are more than an order of magnitude lower than band strengths of bulk-water molecules in ice and liquid water and are similar to those of H2O monomers confined in solid matrices. Adsorption of carbon monoxide with dangling OH bonds results in the appearance of a new broad dangling OH feature at 3680–3620 cm‑1, with a band strength of 1.8 ± 0.1 × 10‑17 cm molecule‑1. The band strengths of dangling OH features determined in this study advance our understanding of the surface structure of interstellar ice analogs and recent IR observations of the JWST.

Keywords: Interstellar dust, Dust physics, Infrared spectroscopy, Solid matter physics, Optical constants (Ice), Ice physics, Ice spectroscopy, Surface ices, Interstellar clouds, Spectroscopy, Vibrational spectroscopy, Physical properties (Ice)
Numerical Simulation of Equal Ratio Relations for the Peak Intensities of &gt;10 MeV Energetic Protons. Previous studies have highlighted the significance of perpendicular diffusion in the decay phase of particle intensities for &gt;10 MeV energetic protons. Recently, an observational study has indicated that the peak intensity ratios across different energy channels (13‑64 MeV protons) remain almost constant as the spacecraft location varies in many solar proton events. This interesting phenomenon is referred to as equal ratio relations. These findings suggest that perpendicular diffusion not only affects particle intensity during the decay phase but also throughout the rising phase. In this study, we perform numerical simulations of &gt;10 MeV energetic proton events observed by STEREO A, STEREO B, and the Solar and Heliospheric Observatory. Our findings demonstrate that perpendicular diffusion strongly affects the entire time profile of particle intensity for spacecraft not magnetically connected to the source region. The numerical simulation results indicate that in order to reproduce observations, we need to include perpendicular diffusion near the source region and in interplanetary space. Perpendicular diffusion leads to nearly uniform peak ratios at different locations and contributes to the formation of the reservoir phenomenon during the decay phase. Consequently, these numerical results support the significant role of perpendicular diffusion in the formation of the longitudinal distribution of &gt;10 MeV proton events.

Keywords: Solar energetic particles, Solar wind, Solar flares
AT2021lwx: Another Neutrino-coincident Tidal Disruption Event with a Strong Dust Echo?. We discuss the possible association of an astrophysical neutrino (IC220405B) with the recently reported, extremely energetic tidal disruption event (TDE) candidate AT2021lwx (ZTF20abrbeie, aka "Scary Barbie") at redshift z = 0.995. Although the TDE is about 2.°6 off the direction of the reconstructed neutrino event (outside the 90% confidence level localization region), the TDE candidate shares some important characteristics with so-far-reported neutrino–TDE associations: a strong infrared dust echo, high bolometric luminosity, a neutrino time delay with respect to the peak mass accretion rate of the order of a hundred days, and a high observed X-ray luminosity. We interpret this new association using an isotropic emission model, where neutrinos are produced by the collision of accelerated protons with infrared photons. After accounting for the high redshift of AT2021lwx (by interpreting the data in the supermassive black hole (SMBH) frame), we find that the expected neutrino fluences and neutrino time delays are qualitatively comparable to the other TDEs. Since data are only available up to 300 days postpeak in the SMBH frame, significant uncertainties exist in the dust echo interpretation, and therefore in the predicted number of neutrinos detected,  Nν≃3.0×10‑3‑0.012 . We recommend further follow-up of this object for an extended period and suggest refining the reconstruction of the neutrino arrival direction in this particular case.

Keywords: Neutrino astronomy, Tidal disruption, High energy astrophysics, Radiative processes
The Dynamic Response of Jovian Magnetotail Reconnection to Enhanced Solar Wind Ram Pressure. In this study, we employ the Grid Agnostic Magnetohydrodynamic (MHD) for Extended Research Applications (GAMERA), a high-resolving-power, three-dimensional global MHD model, to simulate magnetotail reconnection in Jupiter's magnetosphere. While previous satellite observations have provided initial statistics on magnetotail reconnection properties at Jupiter, they have been limited in spacetime coverage, leaving the dynamic process of Jovian magnetotail reconnection and its response to the solar wind (SW) poorly understood. Using MHD simulations, we quantitatively analyze the temporal evolution and spatial dependence of nightside reconnection in Jupiter's magnetotail under ideal quiet and enhanced SW conditions. Our results demonstrate that magnetotail reconnection tends to occur in the midnight and postmidnight sectors, with a low occurrence in the premidnight sector, consistent with both Galileo and Juno observations and predictions by Delamere &amp; Bagenal. The magnetic local time (MLT)–radial distribution of magnetotail reconnection is broad, indicating that Jovian magnetotail reconnection is always dynamic rather than steady state. Enhanced SW ram pressure can decrease the MLT coverage of magnetotail reconnection by compressing Jupiter's magnetosphere. However, the occurrence of magnetotail reconnection near the midnight and postmidnight sectors is enhanced by SW compression beyond 60 R J, but is not significantly impacted by SW compression within 60 R J. Conversely, SW compression suppresses reconnection in the premidnight sector, leading to a stronger dawn–dusk asymmetry in the occurrence and location of magnetotail reconnection. This study validates the applicability of the GAMERA code for simulating Jupiter's magnetosphere and provides complementary insights into the dynamic structure and the SW response of Jupiter's magnetosphere.

Keywords: Planetary magnetospheres, Jupiter
Expected Gamma-Ray Burst Detection Rates and Redshift Distributions for the BlackCAT CubeSat Mission. We report the results of an extensive set of simulations exploring the sensitivity of the BlackCAT CubeSat to long-duration gamma-ray bursts (GRBs). BlackCAT is a NASA APRA-funded CubeSat mission for the detection and real-time subarcminute localization of high-redshift (z ≳ 3.5) GRBs. Thanks to their luminous and long-lived afterglow emissions, GRBs are uniquely valuable probes of high-redshift star-forming galaxies and the intergalactic medium. In addition, each detected GRB with a known redshift serves to localize a region of high-redshift star formation in three dimensions, enabling deep follow-on searches for host galaxies and associated local and large-scale structures. We explore two distinct models for the GRB redshift distribution and luminosity function, both consistent with Swift observations. We find that, for either model, BlackCAT is expected to detect a mean of 42 bursts per year on orbit, with 6.7% to 10% of these at z &gt; 3.5. BlackCAT bursts will be localized to an r 90 ≲ 55″ precision and reported to the community within seconds. Due to the mission orbit and pointing scheme, bursts will be located in the night sky and well placed for deep multiwavelength follow-up observations. BlackCAT is on schedule to achieve launch readiness in 2025.

Keywords: Gamma-ray bursts, X-ray telescopes, Star formation, Transient detection, High-redshift galaxies