Sazuna/UAT_keywords huggingface dataset:
Observational Biases on Rotation Curves from Integral Field Unit Data at Cosmic Noon. Through studying rotation curves, which depict how the velocity of the stars and gas changes with distance from the center of a galaxy, it has been confirmed that dark matter dominates galaxies' outer regions, as their rotation curve remains flat. However, recent studies of star-forming galaxies at cosmic noon have shown a decline in their rotation curve beyond a certain point, suggesting a decrease of the abundance of dark matter in galactic halos during earlier times. In this work, we investigate the influence of cosmological surface brightness dimming and loss of resolution on observations of rotation curves at cosmic noon. We used a sample of 19 Lyman break analogs at z ∼ 0.2 and artificially redshifted them as if they were at z ∼ 2.2. By comparing both rotation curves of the observed and mocked objects, we find that the asymmetry of the cosmic noon galaxies is smaller than that of the low-z galaxies. In low-z galaxies, asymmetry increases with radius and becomes relevant at the external parts, where mergers and interactions cause more disturbance in the galaxy's gravitational field. In contrast, cosmic-noon galaxies appear smoother, smaller, and suitable for dynamical modeling—when in reality they are not. The combined effects of the cosmological bias and loss of resolution lead us to the conclusion that caution should be exercised when using cosmic-noon rotation curves, as they might not accurately trace the gravitational potential of the galaxy.

Keywords: Galaxy rotation curves, Galaxy kinematics, Dark matter
Contribution of Globular Clusters to Diffuse Gamma-Ray Emission from the Galactic Plane. The diffuse Galactic gamma-ray emission (DGE) provides a valuable probe for investigating the cosmic-ray propagation and interactions within our Galactic environment. Recent observations have demonstrated systematic excesses of DGE compared with the conventional cosmic-ray propagation model predictions. While gamma-ray emissions have been detected in a subset of globular clusters, their undetected populations may significantly contribute to the DGE. Motivated by this possibility, we present a comprehensive assessment of potential contributions from unresolved globular clusters to the DGE. In our analysis, a nonparametric method is employed to estimate the luminosity function and spatial distribution function of globular clusters using the Fermi-Large Area Telescope (LAT) fourth source catalog (4FGL) combined with a reference globular cluster catalog. Based on these distributions, we calculate the cumulative contribution of unresolved globular cluster populations to the DGE observed by Fermi-LAT and the Large High Altitude Air Shower Observatory. Our results reveal that globular clusters account for only ∼2% of the DGE at the TeV range, and smaller than 1% in the GeV regime, which is effectively negligible.

Keywords: Globular star clusters, Gamma-ray astronomy, Diffuse radiation, Cosmic background radiation
Ultraviolet and Gravitational Wave Signatures of Magnetar Formation. We investigate the impact of gravitational wave (GW) emission by a newly born magnetar onto its electromagnetic (EM) counterparts in the Ultraviolet Transient Astronomy Satellite (ULTRASAT) band. In particular, we carry out a numerical calculation of magnetar-powered shock breakouts (SBOs) and supernova (SN) light curves. We find that an early SBO peak in the bolometric light curves provides a likely signature of a magnetar central engine, which can help constrain the magnetar's spin period and magnetic dipole. Moreover, our results show that GW emission by the magnetar has only a minor effect on the SBO light curve. Such SBOs can be detected by ULTRASAT at a rate ∼1–2 yr‑1, provided that the magnetar wind is not efficiently thermalized during the early phases of the evolution. We additionally find that the subsequent SN light curves can be more luminous than SBOs in the ULTRASAT band and can thus be detected at a higher rate. Finally, we find a possible late-time signature of GW emission in the SN light curves, which may provide an additional tool for the detection of GW signals. Our results demonstrate that future ULTRASAT observations will provide crucial insights into the magnetar formation process and unique information for direct searches of long-transient signals with current and future generation GW detectors. In particular, we estimate a rate of multimessenger (UV+GW) detections of newly formed magnetars ≳1 every 2 yr with ULTRASAT and the Einstein Telescope.

Keywords: Ultraviolet astronomy, Magnetars
Reprocessing of the Parkes 70 cm Survey and Discovery of a New Radio Pulsar in the Large Magellanic Cloud. We have reprocessed the data archived from the Parkes 70 cm (PKS70) pulsar survey with an expanded dispersion measure (DM) search range and an acceleration search. Our goal was to detect pulsars that might have been missed in the original survey processing. Of the original 43,842 pointings, 34,869 pointings were archived, along with 440 additional pointings for confirmation or timing. We processed all of these archived data and detected 359 known pulsars: 265 of these were detected in the original survey, while an additional 94 currently known pulsars were detected in our reprocessing. A few among those 94 pulsars are highly accelerated binary pulsars. Furthermore, we detected 5 more pulsars with DMs higher than the original survey thresholds, as well as 6 more pulsars below the nominal survey sensitivity threshold (from the original survey beams with longer integrations). We missed detection of 33 (of the 298) pulsars detected in the original survey, in part because of portions of the survey data missing in the archive and our early-stage candidate sifting method. We discovered one new pulsar in the reanalysis, PSR J0540−69, which has a spin period of 0.909 s and resides in the Large Magellanic Cloud (LMC). This new pulsar appeared in three PKS70 beams and one additional L-band observation that targeted the LMC pulsar PSR B0540−69. The numerous pulsar detections found in our reanalysis and the discovery of a new pulsar in the LMC highlight the value of conducting multiple searches through pulsar data sets.

Keywords: Surveys, Radio pulsars
PEARLS: Globular Clusters and Ultracompact Dwarfs in the El Gordo Galaxies at z = 0.87. JWST/NIRCam 0.9 to 2.0 μm images reveal a population of point sources around the major galaxies in the El Gordo cluster at redshift z = 0.87. Their distribution in the color─magnitude diagrams shows a narrow sequence well separated from field-galaxy contamination and consistent with their identification as ultracompact dwarf galaxies (UCDs) or luminous globular clusters (GCs). The point-source sequence is more luminous by almost a magnitude than the corresponding sequence in Abell 2744 at z = 0.31, matching the predicted evolutionary change for GC/UCDs over the 4 Gyr difference in look-back time between these two clusters. Deeper observations should allow direct JWST imaging of GC/UCD populations, even without the help of lensing, up to z ∼ 1.4, a look-back time of more than 9 Gyr. Such observations would directly reveal the evolution of these compact stellar systems two-thirds of the way back to the Big Bang.

Keywords: Globular star clusters, Brightest cluster galaxies, Galaxy clusters
The Energy Cascade Rate in Supersonic Magnetohydrodynamic Turbulence. Three-dimensional direct numerical simulations are implemented to investigate the energy cascade rate in compressible isothermal magnetohydrodynamic turbulence. Utilizing an exact law derived from the Kármán–Howarth equation, we examine the contributions of flux and nonflux terms to the cascade rate across a broad range of sonic and Alfvénic Mach numbers, from subsonic to supersonic regimes and with varying mean magnetic fields. The cascade rates are computed using on-grid 3D decomposition and two plasma increment approaches: signed and absolute values. The anisotropy induced by strong magnetic fields is analyzed through angular-dependent scaling of the cascade terms. Moreover, the increment calculation method significantly influences the relative contributions of the flux and nonflux terms, with absolute methods tending to overestimate the latter. These findings extend current studies of compressible turbulence and offer critical insights into energy transfer mechanisms relevant to many astrophysical phenomena.

Keywords: Interplanetary turbulence, Magnetohydrodynamics, Plasma physics
The superMIGHTEE Project: MeerKAT and GMRT Together to Unveil the Deep Radio Sky. An international team of researchers has come together to undertake an ultra-broadband exploration of the deep radio sky. The superMIGHTEE project combines data from the MIGHTEE project, using the precursor Square Kilometre Array MeerKAT telescope in South Africa, with observations from the upgraded Giant Metrewave Radio Telescope (uGMRT) in India to produce deep images at several μJy sensitivity over a frequency range of 200 MHz–2.5 GHz, with an angular resolution of a few arcseconds. This paper describes the initial superMIGHTEE uGMRT data release, comprising total intensity continuum images covering a total of 9.9 deg2 at 650 MHz and 6.9 deg2 at 400 MHz in the XMM-LSS, COSMOS, and E-CDFS deep fields. The associated radio source catalogues include 27,101 sources at 650 MHz and 10,946 sources at 400 MHz. The redshift distribution of the sources extends to z ∼ 4 with a median value of z = 1. An overview of the broadband spectra of the sources, in combination with the MeerKAT MIGHTEE 1280 MHz data, reveals a clear change in spectral properties at the transition from an active galactic nuclei-dominated population to a population dominated by star-forming galaxies at flux densities of a few mJy. At higher frequencies, the star-forming galaxy population exhibits an optically thin synchrotron spectral index indicative of energy injection from supernovae. At lower frequencies, the spectra flatten significantly with decreasing flux density, and the fraction of sources with peaked spectra increases. This is the first superMIGHTEE uGMRT data release. Subsequent releases will include spectro-polarimetric and spectral line image cubes, as well as images at lower frequencies. The goal of the superMIGHTEE ultra-wideband data set is to enhance our understanding of the evolution of active galactic nuclei and star-forming galaxies over cosmic time, shed light on the evolution of neutral hydrogen, and explore the origins and evolution of cosmic magnetic fields in clusters, filaments, and galaxies.

Keywords: Supermassive black holes, Radio galaxies, Active galactic nuclei, Galaxy evolution, Star formation, Radio continuum emission, High-redshift galaxies, Redshift surveys, Astrophysical black holes
Capturing Star Formation Activity from Compressed Photometric Images of Galaxies. We present a novel approach for classifying star-forming galaxies using photometric images. By utilizing approximately 124,000 optical color composite images and spectroscopic data of nearby galaxies at 0.01 &lt; z &lt; 0.06 from the Sloan Digital Sky Survey, along with follow-up spectroscopic line measurements from the OSSY catalog, and leveraging the vision transformer machine learning technique, we demonstrate that galaxy images in JPEG format alone can be directly used to determine whether star-forming activity dominates the galaxy, bypassing traditional spectroscopic analyses such as emission-line diagnostic diagrams. We anticipate that this method holds significant potential for application in current and future large-scale surveys, such as Euclid, the Dark Energy Survey, and the Legacy Survey of Space and Time.

Keywords: Astronomy data analysis, Astronomical methods, Astronomy image processing, Neural networks
Primordial Black Hole Triggered Type Ia Supernovae. I. Impact on Explosion Dynamics and Light Curves. Primordial black holes (PBHs) in the asteroid-mass window are compelling dark matter candidates, made plausible by the existence of black holes and by the variety of mechanisms of their production in the early Universe. If a PBH falls into a white dwarf (WD), the strong tidal forces can generate enough heat to trigger a thermonuclear runaway explosion, depending on the WD's mass and the PBH's orbital parameters. In this work, we investigate the WD explosion triggered by the passage of a PBH. We perform 2D simulations of the WD undergoing thermonuclear explosion in this scenario, with the predicted ignition site as a parameter assuming the deflagration–detonation transition model. We study the explosion dynamics, and predict the associated light curves and nucleosynthesis. We find that the model sequence predicts light curves which align with the Phillips relation ( Bmax  versus ΔM15). Our models hint at a unifying approach in triggering Type Ia supernovae without involving two distinctive evolutionary tracks.

Keywords: Hydrodynamical simulations, Explosive nucleosynthesis, Light curves, Type Ia supernovae, Dark matter, Primordial black holes
Rotational Dynamics in Pulsational Pair-instability Supernovae: Implications for Mass Loss and Transient Events. Pulsational pair-instability supernovae (PPISNe) are transient events occurring in progenitor stars with He cores of ∼32–65 M⊙, where rapid electron–positron pair production induces pressure loss, collapse, and pulsations driving episodic mass loss. The number, strength, and duration of these pulses can lead to shell collisions that produce shock-powered transients, potentially explaining some of the most luminous events, such as superluminous supernovae, and other rare transients. Rapid progenitor rotation lowers the PPISN mass threshold and influences the dynamics, energetics, and chemical composition of PPISN-driven pulses. In this study, we computed 1D evolutionary models of massive, rotating PPISN progenitor stars with ZAMS masses of 85–140 M⊙ and metallicities of Z⊙ and 0.1 Z⊙. Our analysis reveals strong correlations between PPISN ejected mass and total energy, as well as between ejected mass and peak ejected shell velocity. Additionally, moderate correlations indicate that higher initial PPISN progenitor mass leads to greater mass ejection and energy release, while negative correlations show that rapid rotation appears to reduce mass ejection and kinetic energy of the shells. Subsequent pulses lead to H-poor, C- and O-enriched ejected shells, indicating the effect of rotationally induced chemical mixing, PPISN-driven episodic mass loss with implications for their transients. We model the light curve and synthetic spectra that arise from the collision of two H-poor shells for one of our models using the radiation transport code SuperLite. We find that shock-heated H-poor PPISN shell collisions from rapidly rotating progenitors can lead to moderately luminous H-poor transients that share some similarities with observed superluminous supernova I events.

Keywords: Ejecta, Massive stars, Transient sources, Circumstellar shells, Stellar rotation, Supernovae
Jet Collimation Profile of the Low-luminosity Active Galactic Nucleus M84: Insight into the Jet Formation in the Low-accretion Regime. Recent advancements in high-resolution very long baseline interferometry have significantly improved our understanding of jet collimation near supermassive black holes in active galactic nuclei (AGNs), particularly in high-power systems. However, the collimation properties of jets in low-luminosity AGNs (LLAGNs) remain poorly explored. In this study, we investigate the jet structure of M84, a nearby radio galaxy and a representative LLAGN, to probe jet collimation properties in the low-accretion regime. Utilizing astrometric phase-referencing observations from the Very Long Baseline Array, supplemented by archival Very Large Array data, we trace the jet geometry of M84 over a broad range of scales, from ∼102 to ∼107 Schwarzschild radii (rs). Our analysis reveals a well-defined transition from a semiparabolic profile, W(r) ∝ r0.71, to a conical shape, W(r) ∝ r1.16, occurring at approximately 1.67 × 104 rs. This indicates that the M84 jet is notably less collimated than those in other known LLAGN sources. Our findings provide new insights into the relationship between jet collimation and accretion rate, offering crucial constraints for jet formation models of LLAGNs.

Keywords: Accretion, Very long baseline interferometry, Relativistic jets, Radio galaxies, Active galactic nuclei, Magnetic fields
SDSS-IV MaNGA: Physical Origins of Double-peaked Narrow Emission-line Spaxels in Barred Galaxies. The physical origins of double-peaked narrow emission-line spaxels (DPSs) in barred galaxies are explored through the analysis of a sample of 72 barred double-peaked emission-line galaxies (DPGs) extracted from the MaNGA data set. In this study, we examine two potential scenarios: the gas inflow along the bar and the formation of a bar-induced gaseous nuclear ring. By applying a classical galactic dynamics model, we calculate the radii and rotational velocities of the nuclear rings for all barred DPGs and compare them with the observed properties of their DPSs. Our analysis reveals a significant correlation between the predicted radii of the nuclear rings and the maximum centric distances of the DPSs, as well as a marginal correlation between the predicted rotational velocities of the nuclear rings and the observed maximum velocity differences of the DPSs. These findings provide strong evidence to support the hypothesis that the DPSs of a barred DPG in MaNGA primarily originate from the convolution of the point-spread function effect with its bar-induced fast-rotating gaseous nuclear ring.

Keywords: Barred spiral galaxies, Ring galaxies, Galaxies
On the Origin and Dynamical Evolution of Jupiter's Moon Amalthea. Interior to the orbits of Jupiter's iconic Galilean moons are four small satellites with individual mean radii R ≲ 84 km. Multiple lines of evidence suggest that these bodies formed at a more distant location in Jupiter's circumplanetary disk before coming to reside at their current short-period orbits. However, how these moons dynamically evolved to such a location has yet to be explained in the emerging paradigm of Jovian satellite formation. Here, we present a quantitative model for the origin of the largest of these inner moons, Amalthea, that can be extended to its neighbor, Thebe, and to other small bodies in astrophysical disks. We propose that Amalthea's anomalous features are due to it having formed alongside the Galileans in a reservoir of satellitesimals located at a large Jovian-centric distance. As the innermost Galilean, Io, migrated inward from this reservoir, it captured the satellitesimal Amalthea into resonance and shepherded the small body to its modern neighborhood. During this migration through the disk, dissipative forcing from aerodynamic drag induces overstable librations in the Io─Amalthea resonance, such that only a narrow range of nebular parameters can accommodate the requisite long-range transport. In particular, the disk aspect ratio, h/r, emerges as the key variable. Our calculations indicate that the circumjovian disk had a scale height of h/r ≳ 0.08, implying a relatively hot, actively accreting disk during the epoch of satellite formation. These results thus shed light on the evolution of the Jovian system, along with the more general phenomenon of satellite─disk interactions.

Keywords: Natural satellite dynamics, Natural satellites (Solar system), Solar system gas giant planets, Planetary dynamics, Jovian satellites
Pumping Iron: How Turbulent Metal Diffusion Impacts Multiphase Galactic Outflows. Most numerical simulations of galaxy formation and evolution are unable to properly resolve the turbulent cascade at or below the resolution scale and turbulence models are required to capture the motion of eddies on those unresolved scales. We investigate the impact of turbulent metal diffusion on multiphase outflows originating from dwarf galaxies (Mhalo ∼ 1010‑1011 M⊙). We use our state-of-the-art numerical model for the formation of single stars and nonequilibrium cooling and chemistry. We run the simulations at a resolution of ∼4 M⊙, and resolve individual supernova explosions in terms of hot phase and momentum input. We find that the mass, energy, and metal loading factors are only weakly affected by the inclusion of a metal diffusion model. The metal enrichment factor at low altitudes above the galactic disk is higher by around 20% when the metal diffusion model is included. Specifically, we find more efficient cooling in the cold interstellar medium, due to more efficient metal mixing that leads to shorter cooling times of the warm gas, which becomes available more quickly for star formation. The most striking effect of the metal diffusion model is that, without metal diffusion, there is more rapid cooling in the hot phase and a reduced sound speed by a factor of 2. Specifically, we find that the hot phase is more metal enriched in the case without metal diffusion leading to more rapid overcooling of that phase, which is consistent with the higher sound speed we find in the runs with metal diffusion.

Keywords: Galactic winds, Hydrodynamical simulations, Stellar feedback, Galaxy evolution, Interstellar medium
Searching for Binary Black Hole Subpopulations in Gravitational-wave Data Using Binned Gaussian Processes. Astrophysically motivated population models for binary black hole (BBH) observables are often insufficient to capture the imprints of multiple formation channels. This is mainly due to the strongly parametrized nature of such investigations. Using a nonparametric model for the joint population-level distributions of BBH component masses and effective inspiral spins, we find hints of multiple subpopulations in the third gravitational-wave transient catalog. The higher (more positive) spin subpopulation is found to have a mass spectrum without any feature at in the 30–40M⊙ range, which is consistent with the predictions of isolated stellar binary evolution, simulations for which place the pileup due to pulsational pair-instability supernovae near 50M⊙ or higher. The other subpopulation with effective spins closer to zero shows a feature at 30–40M⊙ and is consistent with BBHs formed dynamically in globular clusters, which are expected to peak around 30M⊙. We also compute merger rates for these two subpopulations and find that they are consistent with the theoretical predictions of the corresponding formation channels. We validate our results by checking their robustness against variations of several model configurations and by analyzing large simulated catalogs with the same model.

Keywords: Gravitational waves, Black holes, Compact objects
Alfvén Wave Heating of Solar Chromosphere Reexamined. Models of heating the weakly ionized solar atmosphere by collisional damping of upward-propagating Alfvén waves, calculated under the assumption that only incompressible (intermediate-mode) MHD waves are involved, have predicted heating rates that do not agree with the empirically inferred radiative energy loss from the chromosphere. The assumption that incompressible intermediate-mode waves can propagate through the inhomogeneous three-dimensional solar atmosphere without coupling to compressible fast- or slow-mode waves is shown to restrict the configuration of the ambient magnetic field, requiring symmetry conditions that are not satisfied in the solar atmosphere. In a magnetic field without those symmetries, propagating Alfvén waves necessarily generate waves in other MHD modes, which must be included in any realistic model of wave heating.

Keywords: Solar chromospheric heating, Alfven waves, Solar magnetic fields