Sazuna/UAT_keywords huggingface dataset:
Shadows Wreak Havoc in Transition Disks. We demonstrate that shadows cast on a protoplanetary disk can drive it eccentric. Stellar irradiation dominates heating across much of these disks, so an uneven illumination can have interesting dynamical effects. Here, we focus on transition disks. We carry out 3D Athena++ simulations, using a constant thermal relaxation time to describe the disk's response to changing stellar illumination. We find that an asymmetric shadow, a feature commonly observed in real disks, perturbs the radial pressure gradient and distorts the fluid streamlines into a set of twisted ellipses. Interactions between these streamlines have a range of consequences. For a narrow ring, an asymmetric shadow can sharply truncate its inner edge, possibly explaining the steep density drop-offs observed in some disks and obviating the need for massive perturbers. For a wide ring, such a shadow can dismantle it into two (or possibly more) eccentric rings. These rings continuously exert torque on each other and drive gas accretion at a healthy rate, even in the absence of disk viscosity. Signatures of such twisted eccentric rings may have already been observed as, e.g., twisted velocity maps inside gas cavities. We advocate for more targeted observations and for a better understanding on the origin of such shadows.

Keywords: Hydrodynamical simulations, Elliptical orbits, Protoplanetary disks, Hydrodynamics
The Cosmic Evolution of the Supermassive Black Hole Population: A Hybrid Observed Accretion and Simulated Mergers Approach. Supermassive black holes (SMBHs) can grow through both accretion and mergers. It is still unclear how SMBHs evolve under these two channels from high redshifts to the SMBH population we observe in the local Universe. Observations can directly constrain the accretion channel but cannot effectively constrain mergers yet, while cosmological simulations provide galaxy merger information but can hardly return accretion properties consistent with observations. In this work, we combine the observed accretion channel and the simulated merger channel, taking advantage of observations and cosmological simulations, to depict a realistic evolution pattern of the SMBH population. With this methodology, we can derive the scaling relation between the black hole mass (M BH) and host-galaxy stellar mass (M ⋆), and the local black hole mass function (BHMF). Our scaling relation is lower than those based on dynamically measured M BH, supporting the claim that dynamically measured SMBH samples may be biased. We show that the scaling relation has little redshift evolution. The BHMF steadily increases from z = 4 to z = 1 and remains largely unchanged from z = 1 to z = 0. The overall SMBH growth is generally dominated by the accretion channel, with possible exceptions at high mass (M BH ≳ 108 M ⊙ or M ⋆ ≳ 1011 M ⊙) and low redshift (z ≲ 1). We also predict that around 25% of the total SMBH mass budget in the local Universe may be locked within long-lived, wandering SMBHs, and the wandering mass fraction and wandering SMBH counts increase with M ⋆.

Keywords: Supermassive black holes, Cosmological evolution
Hybrid Simulations of the Martian Magnetotail Twist. Three-dimensional global hybrid simulations are performed to explore how the interplanetary magnetic field (IMF), the Martian crustal fields, and planetary pickup ions affect the twisting of the Martian magnetotail. The results agree with previous studies that the crustal magnetic fields cause the Martian magnetotail to twist counterclockwise or clockwise depending on the sign of the IMF Y-component in the Mars solar orbital coordinates. However, the twist is more pronounced when the crustal fields are on the nightside, contradicting the early explanation that the crustal fields affect the twist through dayside magnetic reconnection between the crustal fields and the draped IMF. Additionally, planetary pickup ions also contribute to the twist because their mass loading slows down the plasma flow and leads to the bending of the magnetic field lines in the magnetotail. It is demonstrated that the twist inside Mars' shadow in the near magnetotail region (at X = −1.5 R M, where R M is Mars' radius) is mainly attributable to the crustal fields, while the influence of planetary pickup ions starts to dominate outside Mars' shadow and in regions further away from Mars.

Keywords: Magnetic anomalies, Mars, Solar-planetary interactions, Pickup ions, Planetary magnetospheres
Search for Joint Multimessenger Signals from Potential Galactic Cosmic-Ray Accelerators with HAWC and IceCube. The origin of high-energy galactic cosmic rays is yet to be understood, but some galactic cosmic-ray accelerators can accelerate cosmic rays up to PeV energies. The high-energy cosmic rays are expected to interact with the surrounding material or radiation, resulting in the production of gamma-rays and neutrinos. To optimize for the detection of such associated production of gamma-rays and neutrinos for a given source morphology and spectrum, a multimessenger analysis that combines gamma-rays and neutrinos is required. In this study, we use the Multi-Mission Maximum Likelihood framework with IceCube Maximum Likelihood Analysis software and HAWC Accelerated Likelihood to search for a correlation between 22 known gamma-ray sources from the third HAWC gamma-ray catalog and 14 yr of IceCube track-like data. No significant neutrino emission from the direction of the HAWC sources was found. We report the best-fit gamma-ray model and 90% CL neutrino flux limit from the 22 sources. From the neutrino flux limit, we conclude that, for five of the sources, the gamma-ray emission observed by HAWC cannot be produced purely from hadronic interactions. We report the limit for the fraction of gamma-rays produced by hadronic interactions for these five sources.

Keywords: High energy astrophysics, Gamma-ray astronomy, Neutrino astronomy, Particle astrophysics
Limb Observations of Global Solar Coronal Extreme-ultraviolet Wavefronts: The Inclination, Kinematics, Coupling with the Expanding Coronal Mass Ejections, and Connection with the Coronal Mass Ejection Driven Shocks. We select and investigate six global solar extreme-ultraviolet (EUV) wave events using data from the Solar Dynamics Observatory and the Solar and Heliospheric Observatory. These eruptions are all on the limb but recorded as halo coronal mass ejections (CMEs) because the CME-driven shocks have expanded laterally to the opposite side. With the limb observations avoiding the projection effect, we have measured the inclination and speed of the EUV wavefront from 1.05 to 1.25 R ⊙. We also investigate the coupling and connection of the EUV wavefront with the CME boundary and the CME-driven shock, respectively. The major findings in the six events are: (1) the forward inclination of the primary and coronal-hole-transmitted EUV wavefronts is estimated, respectively, and the origins of these inclinations and their effects on the estimate of actual wavefronts speed are investigated; (2) the wavefront speed can be elevated by loop systems near the coronal base, and the average speed in the low corona has no clear correlation with the lateral expansion of the CME-driven shock in the high corona; (3) the fast magnetosonic Mach number of the wavefront is larger than unity from the coronal base; (4) the EUV wavefront is coupled with the CME driver throughout the propagation in two events; (5) after the EUV wavefront vanishes, the CME-driven shock continues traveling on the opposite side and disconnects from the EUV wavefront in four events. These results and their implications are discussed, which provide insight into the properties of global EUV waves.

Keywords: Solar coronal mass ejection shocks, Solar storm, Solar coronal waves, Solar extreme ultraviolet emission
Electron Acceleration at Quasi-parallel Nonrelativistic Shocks: A 1D Kinetic Survey. We present a survey of 1D kinetic particle-in-cell simulations of quasi-parallel nonrelativistic shocks to identify the environments favorable for electron acceleration. We explore an unprecedented range of shock speeds v sh ≈ 0.067–0.267c, Alfvén Mach numbers  MA=5–40 , sonic Mach numbers  Ms=5–160 , as well as the proton-to-electron mass ratios m i/m e = 16–1836. We find that high Alfvén Mach number shocks can channel a large fraction of their kinetic energy into nonthermal particles, self-sustaining magnetic turbulence and acceleration to larger and larger energies. The fraction of injected particles is ≲0.5% for electrons and ≈1% for protons, and the corresponding energy efficiencies are ≲2% and ≈10%, respectively. The extent of the nonthermal tail is sensitive to the Alfvén Mach number; when  MA≲10 , the nonthermal electron distribution exhibits minimal growth beyond the average momentum of the downstream thermal protons, independently of the proton-to-electron mass ratio. Acceleration is slow for shocks with low sonic Mach numbers, yet nonthermal electrons still achieve momenta exceeding the downstream thermal proton momentum when the shock Alfvén Mach number is large enough. We provide simulation-based parameterizations of the transition from thermal to nonthermal distribution in the downstream (found at a momentum around  pi,e/mivsh≈3mi,e/mi ), as well as the ratio of nonthermal electron to proton number density. The results are applicable to many different environments and are important for modeling shock-powered nonthermal radiation.

Keywords: High energy astrophysics, Plasma physics, Plasma astrophysics, Galactic cosmic rays, Shocks, Magnetic fields, Cosmic rays
Reconstruction of the Total Solar Irradiance During the Last Millennium. Solar irradiance variations across various timescales, from minutes to centuries, represent a potential natural driver of past regional and global climate cold phases. To accurately assess the Sun's effect on climate, particularly during periods of exceptionally low solar activity, known as grand minima, an accurate reconstruction of solar forcing is essential. While direct measurements of the total solar irradiance (TSI) only began in the late 1970s, with the advent of space radiometers, indirect evidence from various historical proxies suggests that the Sun's magnetic activity has undergone possible significant fluctuations over much longer timescales. Employing diverse and independent methods for TSI reconstruction is essential to gaining a comprehensive understanding of this issue. This study employs a semi-empirical model to reconstruct TSI over the past millennium. Our approach uses an estimated open solar magnetic field (F  o ), derived from cosmogenic isotope data, as a proxy for solar activity. We reconstruct the cyclic variations of TSI, due to the solar surface magnetic features, by correlating F  o  with the parameter of active region functional form. We obtain the long-term TSI trend by applying the empirical mode decomposition algorithm to the reconstructed F  o  to filter out the 11 yr and 22 yr solar variability. We prepare a reconstructed TSI record, spanning 971 to 2020 CE. The estimated departure from modern TSI values occurred during the Spörer minimum (around 1400 CE), with a decrease of approximately 2.3 Wm‑2. A slightly smaller decline of 2.2 Wm‑2 is reported during the Maunder minimum, between 1645 and 1715 CE.

Keywords: Solar physics, Solar radiation
The Electric Field and Its Impact on the Pitch Angle of Trapped Electrons in a Sub-ion-scale Magnetic Hole. Sub-ion-scale magnetic holes (MHs) are ubiquitous structures in plasmas across a wide range of environments. Despite previous observational and modeling efforts, the three-dimensional (3D) electric field in MHs has yet to be adequately resolved. In this study, utilizing high-resolution measurements of an MH (∼0.08ρ  i  × 0.14ρ  i ) from the Magnetospheric Multiscale mission in Earth's turbulent magnetosheath, we report this 3D electric field and unveil its roles and generation mechanism. A model is established to quantify the impacts of E ∥ on increasing the loss cone of trapped electrons. The electric field is attributed to electron convection and pressure gradient terms of generalized Ohm's law. The MH, primarily coupling to the electron, is accompanied by electron jets. These electron jets can be interpreted as different segments of an electron vortex. These electron jets combined with nonideal electric fields not only lead to strong energy conversion ( j · ( E + v  e  × B ) ∼ 40 nW m‑3) from the electromagnetic field to electrons but also enable energy conversion between different electron motion directions. Our study significantly clarifies the physical image of kinetic-scale MHs.

Keywords: Space plasmas
Accelerated Structure Formation: The Early Emergence of Massive Galaxies and Clusters of Galaxies. Galaxies in the early Universe appear to have grown too big too fast, assembling into massive, monolithic objects more rapidly than anticipated in the hierarchical Lambda cold dark matter (ΛCDM) structure formation paradigm. The available photometric data are consistent with there being a population of massive galaxies that form early (z ≳ 10) and quench rapidly over a short (≲1 Gyr) timescale, consistent with the traditional picture for the evolution of giant elliptical galaxies. Similarly, kinematic observations as a function of redshift show that massive spirals and their scaling relations were in place at early times. Explaining the early emergence of massive galaxies requires either an extremely efficient conversion of baryons into stars at z &gt; 10 or a more rapid assembly of baryons than anticipated in ΛCDM. The latter possibility was explicitly predicted in advance by modified Newtonian dynamics (MOND). We discuss some further predictions of MOND, such as the early emergence of clusters of galaxies and early reionization.

Keywords: Galaxy formation, Protogalaxies, High-redshift galaxy clusters, Cold dark matter, Galaxy evolution, Modified Newtonian dynamics, Galaxy masses, High-redshift galaxies
A Broad Set of Solar and Cosmochemical Data Indicates High C-N-O Abundances for the Solar System. We examine the role of refractory organics as a major C carrier in the outer protosolar nebula and its implications for the compositions of large Kuiper Belt objects (KBOs) and CI chondrites. By utilizing Rosetta measurements of refractory organics in comet 67P/Churyumov–Gerasimenko, we show that they would make up a large fraction of the protosolar C inventory in the KBO-forming region based on the current widely adopted solar abundances. However, this would free up too much O to form water ice, producing solid material that is not sufficiently rock-rich to explain the uncompressed density of the Pluto–Charon system and other large KBOs; the former has been argued as the most representative value we have for the bulk composition of large KBOs. This inconsistency further highlights the solar abundances problem—an ongoing challenge in reconciling spectroscopically determined heavy-element abundances with helioseismology constraints. By employing a new data set from solar CNO neutrinos and solar wind measurements of C, N, and O, we show that the uncompressed density of the Pluto–Charon system can be reproduced over a wide range of scenarios. We show that a lack of sulfates in Ryugu and Bennu samples implies a lower amount of water ice initially accreted into CI chondrite parent bodies than previously thought. These data are found to be consistent with the solar C/O ratio implied by the new data set. Our predictions can be tested by future neutrino, helioseismology, and cosmochemical measurements.

Keywords: Classical Kuiper belt objects, Solar wind, Solar neutrinos, Solar abundances, Meteorites
Double-peaked Narrow Emission-line Galaxies in SDSS-IV MaNGA. Narrow emission lines in a galaxy's spectrum that show double peaks indicate the presence of distinct gas components with different velocities, and its physical origin remains uncertain. This study uses galaxies from the final MaNGA data release to detect double-peaked narrow emission-line spaxels (DPSs) by examining the double Gaussian profiles of the Hα-[N II] doublets across all MaNGA spaxels. A total of 5420 DPSs associated with 304 double-peaked narrow emission-line galaxies (DPGs) are identified, with each DPG containing a minimum of five DPSs and being free from overlap with other galaxies. We find that DPSs can be categorized into three groups according to their central distance r/R  e  and the velocity difference Δv between their two components: the inner low-Δv, inner high-Δv, and outer DPSs. By incorporating the physical characteristics of the DPGs into their DPSs, we demonstrate for the first time the existence of statistical correlations between barred DPGs and inner low-Δv DPSs, AGN-hosting DPGs, and inner high-Δv DPSs, as well as tidal DPGs and outer DPSs.

Keywords: Galaxy kinematics, Emission line galaxies
The VIRUS-dE Survey. I. Stars in Dwarf Elliptical Galaxies—3D Dynamics and Radially Resolved Stellar Initial Mass Functions. We analyze the stellar structure of a sample of dwarf ellipticals (dEs) inhabiting various environments within the Virgo cluster. Integral-field observations with a high spectral resolution allow us to robustly determine their low-velocity dispersions (∼25 km s‑1) and higher-order kinematic moments out to the half-light radius. We find the dEs exhibit a diversity in ages, with the younger dEs being less enhanced than the older, suggesting a complex star formation history for those dEs that recently entered Virgo, while others have been quenched shortly after reionization. Orbit-superposition modeling allowed us to recover viewing angles, stellar mass-to-light ratios (with gradients), as well as the intrinsic orbit structure. We find that the angular momentum of the dEs is strongly suppressed compared to ordinary early-type galaxies and correlates with the environment. Flattened dEs are so because of a suppressed kinetic energy perpendicular to their equatorial plane. Combining population and dynamical modeling results, we find an age-dependent stellar initial mass function or, alternatively, evidence for a more extended star formation history for those galaxies that have had higher initial mass and/or inhabited lower-density environments. dEs appear to have a spatially homogeneous stellar structure, but the state they were "frozen" in as they stopped forming stars varies dramatically according to their initial conditions.

Keywords: Galaxy formation, Virgo Cluster, Stellar kinematics, Galaxy structure, Dwarf galaxies, Dwarf elliptical galaxies, Mass-to-light ratio
The VIRUS-dE Survey. II. Cuspy and Round Halos in Dwarf Ellipticals—A Result of Early Assembly?. We analyze the dark matter (DM) halos of a sample of dwarf ellipticals (dEs) and discuss cosmological and evolutionary implications. Using orbit modeling, we recover their density slopes and, for the first time, halo flattening. We find that the "cusp-core" tension is mild; on average, dEs have central slopes slightly below the Navarro–Frenk–White predictions. However, the measured flattenings are still more spherical than cosmological simulations predict. Unlike brighter early-type galaxies, the total density slopes of dEs are shallower, and their average DM density does not follow their scaling relation with luminosity. Conversely, dE halos are denser and the densities steeper than in late-type galaxies. We find average DM density and slope are strongly correlated with the environment and moderately with the angular momentum. Central, nonrotating dEs have dense and cuspy halos, whereas rotating dEs in Virgo's outskirts are more cored and less dense. This can be explained by a delayed formation of the dEs in the cluster outskirts, or alternatively by the accumulated baryonic feedback that the dEs in the outskirts have experienced during their very different star formation history. Our results suggest halo profiles are not universal (they depend on assembly conditions) and they evolve only mildly due to internal feedback. We conclude dEs in the local Universe have assembled at a higher redshift than local spirals. In these extreme conditions, star formation and halo assembly, for example, were very different, suggesting no new dEs are formed at present.

Keywords: Galaxy dark matter halos, Galaxy formation, Dark matter distribution, Virgo Cluster, Galaxy structure, Dwarf elliptical galaxies
Molecular Hydrogen Line Identifications in Solar Flares Observed by IRIS: Lower Atmospheric Structure from Radiometric Analysis. A rich spectrum of molecular hydrogen (H2) emission lines is seen in sensitive observations from the far-ultraviolet (FUV) channels of the Interface Region Imaging Spectrograph (IRIS) during flare activity in solar active region NOAA Active Region 11861. Based on this observation, we have determined 37 new line identifications by comparing synthetic spectra produced using 1D modeling of H2 fluorescence. To avoid misidentification of the H2 lines, we have also compiled a complete list of atomic line identifications for the IRIS FUV bandpasses from previous work. We carry out analysis of the spatially resolved H2 emission that occurs during the flares and find the following: (1) in spatially resolved observations the H2 line ratios may show optically thick line formation, contrary to previous results; (2) comparison of the spatial distribution of H2 Doppler velocities with those measured from other species reveals that H2 remote sensing probes an intermediate depth in the atmosphere between the photosphere and chromosphere, consistent with expectations from modeling; (3) the relationship between H2 line intensity and the observed intensity of its exciter is related to the atmospheric stratification; however, (4) H2 fluorescence can sometimes occur in response to radiation from distant sources many megameters away across the solar surface.

Keywords: Spectral line lists, Solar flares, Solar ultraviolet emission, Spectral line identification, Molecular spectroscopy, Solar flare spectra
The Mass and Redshift Dependence of Halo Star Clustering. We adopt the two-point correlation function (2PCF) as a statistical tool to quantify the spatial clustering of halo stars for galaxy systems spanning a wide range in host halo virial mass ( 11.25&lt;log10M200c/M⊙&lt;15 ) and redshifts (0 &lt; z &lt; 1.5) from the IllustrisTNG simulations. Consistent with a previous study, we identify clear correlations between the strength of the 2PCF signals and galaxy formation redshifts, but over a much wider mass range. We find that such correlations are slightly stronger at higher redshifts and get weakened with the increase of host halo mass. We demonstrate that the spatial clustering of halo stars is affected by two factors: (1) the clustering gets gradually weakened as time passes (phase mixing); (2) newly accreted stars at more recent times would increase the clustering. For more massive galaxy systems, they assemble late, and the newly accreted stars would increase the clustering. The late assembly of massive systems may also help to explain the weaker correlations between the 2PCF signals and the galaxy formation redshifts in massive halos, as their 2PCFs are affected more by recently accreted stars, while formation redshift characterizes mass accretion on a much longer timescale. We find that the orbits of satellite galaxies in more massive halos maintain larger radial anisotropy, reflecting the more active accretion state of their hosts while also contributing to their stronger mass loss rates.

Keywords: Halo stars, Two-point correlation function