Sazuna/UAT_keywords huggingface dataset:
A 22 Billion M<SUB>⊙</SUB> Black Hole in Holmberg 15A with Keck KCWI Spectroscopy and Triaxial Orbit Modeling. Holmberg 15A (H15A), the brightest cluster galaxy of A85, has an exceptionally low central surface brightness even among local massive elliptical galaxies with distinct stellar cores, making it exceedingly challenging to obtain high-quality spectroscopy to detect a supermassive black hole (SMBH) at its center. Aided by the superb sensitivity and efficiency of KCWI at the Keck II Telescope, we have obtained spatially resolved stellar kinematics over a ∼100″ × 100″ contiguous field of H15A for this purpose. The velocity field exhibits a low-amplitude (∼20 km s−1) rotation along a kinematic axis that is prominently misaligned from the photometric major axis, a strong indicator that H15A is triaxially shaped with unequal lengths for the three principal axes. Using 2500 observed kinematic constraints, we perform extensive calculations of stellar orbits with the triaxial Schwarzschild code, TriOS, and search over ∼40,000 galaxy models to simultaneously determine the mass and intrinsic 3D shape parameters of H15A. We determine a ratio of p = 0.89 for the middle-to-long principal axes and q = 0.65 for the short-to-long principal axes. Our best estimate of the SMBH mass,  , makes H15A—along with NGC 4889—the galaxy hosting the most massive SMBHs known in the local Universe. Both SMBHs lie significantly above the mean MBH─σ scaling relation. Repeating the orbit modeling with the axisymmetrized version of TriOS produces worse fits to the KCWI kinematics and increases MBH to (2.55 ± 0.20) × 1010 M⊙, which is still significantly below the MBH = (4.0 ± 0.8) × 1010 M⊙ reported in a prior axisymmetric study of H15A.

Keywords: Supermassive black holes, Galaxy dark matter halos, Galaxy dynamics, Early-type galaxies, Galaxy kinematics, Galaxy evolution, Galaxy masses, Galaxies
Do Unusually Cold Starburst Galaxies Exist? A Case Study. We report observations of CO(J = 9 → 8) and OH+(N = 1 → 0) toward the four millimeter-selected lensed starburst galaxies SPT 2354−58, 0150−59, 0314−44, and 0452−50, using the Atacama Large Millimeter/submillimeter Array (ALMA) Atacama Compact Array, as part of a larger study of OH+ in the early Universe. In this work, we use these observations for the main purpose of spectroscopic redshift measurements. For all sources except SPT 0452−50, we confirm the previously reported most likely redshifts, and we find typical CO and OH+ properties for massive starbursts. For SPT 0452−50, we rule out the previously reported value of z = 2.0105, measuring a firm redshift of z = 5.0160 based on [O I], [C II], H2O, and CO emission instead when adding in ancillary ALMA data. Previously, SPT 0452−50 was considered an outlier in relations between dust temperature, far-infrared luminosity, and redshift, which may have hinted at an unusually cold starburst with a dust temperature of only Tdust = (21 ± 2) K. Instead, our new measurements suggest it to be among highly luminous massive dusty starbursts at z &gt; 5, with rather typical properties within that population. We find a revised dust temperature of Tdust = (76.2 ± 2.5) K, and an updated lensing-corrected far-infrared luminosity (42.5─122.5 μm) of (2.35 ) × 1013 L⊙, i.e., about an order of magnitude higher than previously reported. We thus do not find evidence for the existence of unusually cold starburst galaxies in the early Universe that were missed by previous selection techniques.

Keywords: Starburst galaxies, Interstellar line emission, Interstellar line absorption, Millimeter astronomy, Active galaxies, Infrared excess galaxies, Galaxy evolution, Submillimeter astronomy, High-redshift galaxies
ALMA Observations of Solar Spicules in a Polar Coronal Hole. We report observations of solar spicules at millimeter wavelengths (mm-λ) using the Atacama Large Millimeter/submillimeter Array (ALMA). These are supplemented by observations in optical, ultraviolet (UV), and extreme ultraviolet (EUV) wavelengths. The observations were made on 2018 December 25 of the northern polar coronal hole. ALMA obtained time-resolved imaging observations at wavelengths of 3 mm (100 GHz; 2 s cadence) and 1.25 mm (239 GHz; ≈2 minutes cadence) with an angular resolution of 2 2 × 1 3 and 1 5 × 0 7, respectively. Spicules observed at mm-λ are easily seen low in the chromosphere whereas spicules in UV bands are seen to extend higher. The spicules observed at mm-λ are seen in absorption against coronal EUV emission, allowing us to estimate the column depth of neutral hydrogen. Spicular emission at mm-λ, due to thermal free–free radiation, allows us to estimate the electron number density as a function of height. We find that spicule densities, inferred from the mm-λ data are uniquely insensitive to assumptions regarding the temperature of plasma in spicules. We suggest that the upward mass flux carried by spicules is unlikely to play a significant role in the mass budget of the solar corona and solar wind, and the transport of hot material into the corona by spicules may not play a significant role in coronal heating. However, the possibility that electric currents, fast kink and torsional waves, or other wave modes carried by spicules may play a role in transporting energy into the solar corona cannot be excluded.

Keywords: Solar atmosphere, Solar ultraviolet emission, Solar extreme ultraviolet emission, Solar wind, Solar spicules, Solar radio emission, Solar chromosphere
Quantifying Baryonic Feedback on the Warm–Hot Circumgalactic Medium in CAMELS Simulations. The baryonic physics shaping galaxy formation and evolution are complex, spanning a vast range of scales and making them challenging to model. Cosmological simulations rely on subgrid models that produce significantly different predictions. Understanding how models of stellar and active galactic nucleus (AGN) feedback affect baryon behavior across different halo masses and redshifts is essential. Using the SIMBA and IllustrisTNG suites from the Cosmology and Astrophysics with MachinE Learning Simulations (CAMELS) project, we explore the effect of parameters governing the subgrid implementation of stellar and AGN feedback. We find that while IllustrisTNG shows higher cumulative feedback energy across all halos, SIMBA demonstrates a greater spread of baryons, quantified by the closure radius and circumgalactic medium (CGM) gas fraction. This suggests that feedback in SIMBA couples more effectively to baryons and drives them more efficiently within the host halo. There is evidence that the different feedback modes are highly interrelated in these subgrid models. The parameters controlling the stellar feedback efficiency significantly impact AGN feedback, as seen in the suppression of black hole mass growth and delayed activation of AGN feedback to higher-mass halos with increasing stellar feedback efficiency in both simulations. Additionally, the AGN feedback efficiency parameters affect the CGM gas fraction at low halo masses in SIMBA, hinting at complex, nonlinear interactions between the AGN and supernova feedback modes. Overall, we demonstrate that stellar and AGN feedback are intimately interwoven, especially at low redshift, due to subgrid implementation, resulting in halo property effects that might initially seem counterintuitive.

Keywords: Hydrodynamical simulations, Active galactic nuclei, Stellar feedback, Circumgalactic medium
AEOS: Transport of Metals from Minihalos following Population III Stellar Feedback. We investigate how stellar feedback from the first stars (Population III) distributes metals through the interstellar and intergalactic medium using the star-by-star cosmological hydrodynamics simulation, AEOS. We find that energy injected from the supernovae (SNe) of the first stars is enough to expel a majority of gas and injected metals beyond the virial radius of halos with mass Mdm ≲ 107 M⊙, regardless of the number of SNe. This prevents self-enrichment and results in a nonmonotonic increase in metallicity at early times. Most minihalos (Mdm ≳ 105 M⊙) do not retain significant fractions of the yields produced within their virial radii until they have grown to halo masses of Mdm ≳ 107 M⊙. The loss of metals to regions well beyond the virial radius delays the onset of enriched star formation and extends the period that Population III star formation can persist. We also explore the contributions of different nucleosynthetic channels to 10 individual elements. On the timescale of the simulation (lowest redshift z = 14.3), enrichment is dominated by core-collapse supernovae for all elements, but with a significant contribution from asymptotic giant branch winds to the s-process elements, which are normally thought to only be important at late times. In this work, we establish important mechanisms for early chemical enrichment, which allows us to apply AEOS in later epochs to trace the evolution of enrichment during the complete transition from Population III to Population II stars.

Keywords: Hydrodynamical simulations, Population III stars, Stellar feedback, Galaxy chemical evolution, Dwarf galaxies, Chemical enrichment
Progenitor Diversity in the Accreted Stellar Halos of Milky Way─like Galaxies. Ongoing large stellar spectroscopic surveys of the Milky Way seek to reconstruct the major events in the assembly history of the Galaxy. Chemical and kinematic observations can be used to separate the contributions of different progenitor galaxies to the present-day stellar halo. Here, we compute the number of progenitors that contribute to the accreted stellar halos of simulated Milky Way─like galaxies as a function of radius (the radial diversity) in three suites of models: Bullock &amp; Johnston, Aquarius, and Auriga. We show that there are significant differences between the predictions of these three models, beyond the halo-to-halo scatter expected in ΛCDM. Predictions of diversity from numerical simulations are sensitive to model-dependent assumptions regarding the efficiency of star formation in dwarf galaxies. We compare, at face value, to current constraints on the radial diversity of the Milky Way's accreted halo. These constraints imply that the halo of our Galaxy is dominated by ∼2 progenitors in the range 8─45 kpc, in contrast to averages of 7 progenitors in the Bullock &amp; Johnston models, 3.5 in Aquarius, and 4.2 in Auriga over the same region. We additionally find that the models with radial diversity most similar to that of the Milky Way are predominantly those with ongoing merger events. The Milky Way therefore appears unusual in having an accreted stellar halo dominated by a small number of progenitors accreted at very early times.

Keywords: Galaxy stellar halos, Hydrodynamical simulations, Milky Way Galaxy, N-body simulations
Mapping the Active Galactic Nucleus Effects on the Stellar and Gas Properties of NGC 5806. It is commonly accepted that active galactic nuclei (AGNs) have a strong impact upon the evolution of their host galaxies, but the processes by which they do so are not fully understood. We aim to further the understanding of AGN feeding and feedback by examining an active galaxy using spatially resolved spectroscopy. We analyze integral field spectroscopy of the active galaxy NGC 5806, obtained using the Very Large Telescope Multi-Unit Spectroscopic Explorer. We map the dynamics of gas and stars, as well as gas optical emission line fluxes throughout the central 8 × 8 kpc2 of the galaxy. We use emission line ratios to map gas metallicity and identify regions of gas excitation dominated by AGN/shocks or star formation. We also determine the average stellar population age and metallicity, and model the rotation and dynamics of the galaxy. We find that NGC 5806 has a star-forming circumnuclear ring, with a projected radius of ~400 pc. The dynamics of this galaxy are driven by a large-scale bar, which transports gas from the spiral arm to the central ring and potentially fuels the AGN. We also observe AGN-dominated gas excitation up to 3.3 kpc away from the center of the galaxy, showing the extended AGN effect on the gas in the central regions of the galaxy.

Keywords: AGN host galaxies, Spiral galaxies, Active galaxies, Galaxy dynamics, Seyfert galaxies, Active galactic nuclei, Barred spiral galaxies, Galaxies
Determination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed Dipole. We model an analytical solution to generate the shape of the polar cap structure and discuss the geometrical distortion due to the presence of both longitudinal plasma current flow across the polar cap regime, i.e., polar cap current perturbation, and pulsar rotation, i.e., rotational perturbation. An analytical solution to the parameter space associated with the radio emission geometrical coordinate is produced by using the first- and second-order power series expansion method for the rotationally perturbed dipole case. In general, polar caps show a quasi-elliptical shape, but in the presence of higher-order plasma current our results show that they can be converted into an elliptical structure with a monotonically reduced dimension. Our results show that the rotational effect also leads to a contraction of the dimensions of the polar cap for a given range of the obliquity parameters. We have found that the last open field line constant, as a fraction of the light cylinder radius, decreases in the presence of nonzero plasma current discharge. We also demonstrate that under certain conditions introducing a higher-order plasma current (e.g., with a scale factor ζp = J/JGJ close to 1 in the closed field line region) can lead to a structure resembling a cosmic-combed magnetosphere.

Keywords: Radio pulsars
TransformerPayne: Enhancing Spectral Emulation Accuracy and Data Efficiency by Capturing Long-range Correlations. Stellar spectra emulators often rely on large grids and tend to reach a plateau in emulation accuracy, leading to significant systematic errors when inferring stellar properties. Our study explores the use of Transformer models to capture long-range information in spectra, comparing their performance to the Payne emulator (a fully connected multilayer perceptron), an expanded version of The Payne, and a convolutional-based emulator. We tested these models on synthetic spectral grids, evaluating their performance by analyzing emulation residuals and assessing the quality of spectral parameter inference. The newly introduced TransformerPayne emulator outperformed all other tested models, achieving a mean absolute error (MAE) of approximately 0.15% when trained on the full grid. The most significant improvements were observed in grids containing between 1000 and 10,000 spectra, with TransformerPayne showing 2─5 times better performance than the scaled-up version of The Payne. Additionally, TransformerPayne demonstrated superior fine-tuning capabilities, allowing for pretraining on one spectral model grid before transferring to another. This fine-tuning approach enabled up to a 10-fold reduction in training grid size compared to models trained from scratch. Analysis of TransformerPayne's attention maps revealed that they encode interpretable features common across many spectral lines of chosen elements. While scaling up The Payne to a larger network reduced its MAE from 1.2% to 0.3% when trained on the full data set, TransformerPayne consistently achieved the lowest MAE across all tests. The inductive biases of the TransformerPayne emulator enhance accuracy, data efficiency, and interpretability for spectral emulation compared to existing methods.

Keywords: Astroinformatics, Galactic archaeology, Stellar atmospheres, Astrostatistics
A Unifying Polarization Formalism for Electric and Magnetic Multipole Interactions. We extend the spherical tensorial formalism for polarization to the treatment of electric and magnetic multipole transitions of any order. We rely on the spherical-wave expansion to derive the tensor form of the operator describing the interaction of the atomic system with a polarized radiation field, which naturally leads to the introduction of spherical tensors describing the polarization properties of the interacting field. As a direct application, the formalism is used to model the radiation anisotropy affecting the scattering of radiation in an electric quadrupole transition and the associated Hanle effect in the presence of a magnetic field.

Keywords: Radiative transfer
Neutrino-dominated Relativistic Viscous Accretion Flows around Rotating Black Holes with Shocks. We investigate the relativistic, viscous, advective neutrino-dominated accretion flows (NDAFs) around rotating stellar-mass black holes, incorporating neutrino cooling. By adopting an effective potential to describe the spacetime geometry around the rotating black holes, we self-consistently solve the governing NDAF equations to obtain global transonic accretion solutions. Our findings indicate that, depending on the model parameters, namely, energy (ɛ), angular momentum (λ), accretion rate ( ), viscosity (α), and black hole spin (ak), NDAFs may harbor standing shocks where the Rankine–Hugoniot shock conditions are satisfied. Utilizing these shock-induced NDAF solutions, we compute the neutrino luminosity (Lν) and neutrino annihilation luminosity ( ) across a wide range of model parameters. We further calculate maximum neutrino luminosity ( ) and neutrino annihilation luminosity ( ), resulting in   erg s‑1 (1048‑51 erg s‑1) and   erg s‑1 (1042‑49 erg s‑1) for ak = 0.99 (0.0). These findings suggest that shocked NDAF solutions are potentially promising to explain the energy output of gamma-ray bursts (GRBs). We employ our NDAF model formalism to elucidate   for five GRBs with known redshifts and estimate their accretion rate ( ) based on the spin (ak) of the central source of the GRBs studied here.

Keywords: Accretion, Black hole physics, Shocks, Hydrodynamics
Deciphering Gas Dynamics and Star Formation in a z = 1.1 Main-sequence Spiral Galaxy with ALMA and JWST. We present a joint analysis of high-resolution CO(2─1) and Paschen-α (Paα) emission lines to trace gas dynamics and spatially resolved star formation in ASPECS-LP.3 mm.06, a z = 1.1 main-sequence galaxy. Utilizing data from the Atacama Large Millimeter/submillimeter Array and JWST NIRCam wide field slitless spectroscopy, we explore both ionized gas and molecular gas within this galaxy. With a substantial molecular gas fraction (fmol = 0.44 ± 0.02), ASPECS-LP.3 mm.06 remains on the star-forming main sequence and adheres to the Kennicutt─Schmidt relation, indicating typical gas-to-star conversion efficiency. Our analysis reveals extended structures across multiple wavelengths, suggesting regulated star formation within a stable disk. The spatially resolved star formation efficiency and kinematic analysis indicate that ASPECS-LP.3mm.06 features a smooth mass assembly process across the bulge and disk. Additionally, the galaxy exhibits modest dust extinction (AV = 0.8), potentially linked to self-regulation during bulge formation. These findings position ASPECS-LP.3mm.06 as a prototypical galaxy, offering valuable insights into the mechanisms governing normal disk galaxy growth at z ∼ 1.

Keywords: Galaxy structure, Galaxy evolution, Interstellar medium
Differentiating the Acceleration Mechanisms in the Slow and Alfvénic Slow Solar Wind. In the corona, plasma is accelerated to hundreds of kilometers per second and heated to temperatures hundreds of times hotter than the Sun's surface before it escapes to form the solar wind. Decades of space-based experiments have shown that the energization process does not stop after it escapes. Instead, the solar wind continues to accelerate, and it cools far more slowly than a freely expanding adiabatic gas. Recent work suggests that fast solar wind requires additional momentum beyond what can be provided by the observed thermal pressure gradients alone, whereas it is sufficient for the slowest wind. The additional acceleration for fast wind can be provided through an Alfvén wave pressure gradient. Beyond this fast/slow categorization, however, a subset of slow solar wind exhibits high Alfvénicity that suggests that Alfvén waves could play a larger role in its acceleration compared to conventional slow wind outflows. Through a well-timed conjunction between Solar Orbiter and Parker Solar Probe (PSP), we trace the energetics of slow wind to compare with a neighboring Alfvénic slow solar wind stream. An analysis that integrates remote and heliospheric properties and modeling of the two distinct solar wind streams finds that Alfvénic slow solar wind behaves like fast wind, where a wave pressure gradient is required to reconcile its full acceleration, while non-Alfvénic slow wind can be driven by its nonadiabatic electron and proton thermal pressure gradients. Derived coronal conditions of the source region indicate good model compatibility, but extended coronal observations are required to effectively trace solar wind energetics below PSP's orbit.

Keywords: Slow solar wind, Solar wind, Alfven waves, Chemical abundances
GD-1 Stellar Stream and Cocoon in the DESI Early Data Release. We present ∼115 new spectroscopically identified members of the GD-1 tidal stream observed with the 5000-fiber Dark Energy Spectroscopic Instrument (DESI). We confirm the existence of a "cocoon," which is a broad (FWHM ∼ 2 932 ∼ 460 pc) and kinematically hot (velocity dispersion, σ ∼ 5–8 km s‑1) component that surrounds a narrower (FWHM ∼ 0 353 ∼ 55 pc) and colder [(σ = 3.09 ± 0.76 km s‑1)] thin stream component (based on a median per star velocity precision of 2.7 km s‑1). The cocoon extends over at least a 30∘ segment of the stream observed by DESI. The thin and cocoon components have similar mean values of [Fe/H]: ‑2.54 ± 0.04 dex and ‑2.47 ± 0.06 dex, suggestive of a common origin. The data are consistent with the following scenarios for the origin of the cocoon. The progenitor of the GD-1 stream was an accreted globular cluster (GC) and: (a) the cocoon was produced by pre-accretion tidal stripping of the GC while it was still inside its parent dwarf galaxy; (b) the cocoon comprises debris from the parent dwarf galaxy; (c) an initially thin GC tidal stream was heated by impacts from dark subhalos in the Milky Way; (d) an initially thin GC stream was heated by a massive Sagittarius dwarf galaxy; or a combination of some of these. Future DESI spectroscopy and detailed modeling may enable us to distinguish between these possible origins.

Keywords: Milky Way dark matter halo, Stellar streams, Milky Way dynamics, Atomic spectroscopy, Milky Way stellar halo, Spectroscopy, Dark matter