adsabs/SciX_UAT_keywords huggingface dataset:
GOALS-JWST: Pulling Back the Curtain on the AGN and Star Formation in VV 114

We present results from the James Webb Space Telescope Director's Discretionary Time Early Release Science program 1328 targeting the nearby, luminous infrared galaxy, VV 114. We use the MIRI and NIRSpec instruments to obtain integral-field spectroscopy of the heavily obscured eastern nucleus (V114E) and surrounding regions. The spatially resolved, high-resolution spectra reveal the physical conditions in the gas and dust over a projected area of 2-3 kpc that includes the two brightest IR sources, the NE and SW cores. Our observations show for the first time spectroscopic evidence that the SW core hosts an active galactic nucleus as evidenced by its very low 6.2 μm and 3.3 μm polycyclic aromatic hydrocarbon equivalent widths (0.12 and 0.017 μm, respectively) and mid- and near-IR colors. Our observations of the NE core show signs of deeply embedded star formation including absorption features due to aliphatic hydrocarbons, large quantities of amorphous silicates, as well as HCN due to cool gas along the line of sight. We detect elevated [Fe II]/Pfα consistent with extended shocks coincident with enhanced emission from warm H2, far from the IR-bright cores and clumps. We also identify broadening and multiple kinematic components in both H2 and fine structure lines caused by outflows and previously identified tidal features.

Keywords: interacting galaxies; galaxy nuclei; luminous infrared galaxies; active galactic nuclei
Validation of HD 183579b Using Archival Radial Velocities: A Warm Neptune Orbiting a Bright Solar Analog

As exoplanetary science matures into its third decade, we are increasingly offered the possibility of pre-existing, archival observations for newly detected candidates. This is particularly poignant for the TESS mission, whose survey spans bright, nearby dwarf stars in both hemispheres—precisely the types of sources targeted by previous radial velocity (RV) surveys. On this basis, we investigated whether any of the TESS Objects of Interest (TOIs) coincided with such observations, from which we find 18 single-planet candidate systems. Of these, one exhibits an RV signature that has the correct period and phase matching the transiting planetary candidates with a false-alarm probability of less than 1%. After further checks, we exploit this fact to validate HD 183579b (TOI-1055b). This planet is <4 R⊕ and has better than 33% planetary mass measurements, thus advancing TESS' primary objective of finding 50 such worlds. We find that this planet is among the most accessible small transiting planets for atmospheric characterization. Our work highlights that the efforts to confirm and even precisely measure the masses of new transiting planet candidates need not always depend on acquiring new observations—in some instances, these tasks can be completed with existing data.

Keywords: astronomical techniques; exoplanet detection methods
Imaging the Inner Astronomical Unit of the Herbig Be Star HD 190073

The inner regions of protoplanetary disks host many complex physical processes such as star-disk interactions, magnetic fields, planet formation, and the migration of new planets. To study directly this region requires milliarcsecond angular resolution, beyond the diffraction limit of the world's largest optical telescopes and even too small for the millimeter-wave interferometer Atacama Large Millimeter/submillimeter Array (ALMA). However, we can use infrared interferometers to image the inner astronomical unit. Here, we present new results from the CHARA and VLTI arrays for the young and luminous Herbig Be star HD 190073. We detect a sub-astronomical unit (sub-AU) cavity surrounded by a ring-like structure that we interpret as the dust destruction front. We model the shape with six radial profiles, three symmetric and three asymmetric, and present a model-free image reconstruction. All the models are consistent with a near face-on disk with an inclination ≲20°, and we measure an average ring radius of 1.4 ± 0.2 mas (1.14 au). Around 48% of the total flux comes from the disk with 15% of that emission appearing to emerge from inside the inner rim. The cause of emission is still unclear, perhaps due to different dust grain compositions or gas emission. The skewed models and the imaging point to an off-center star, possibly due to binarity. Our image shows sub-AU structure, which seems to move between the two epochs inconsistently with Keplerian motion and we discuss possible explanations for this apparent change.

Keywords: young stellar objects; herbig ae/be stars; protoplanetary disks; long baseline interferometry
GRMHD Simulations of Neutron-star Mergers with Weak Interactions: r-process Nucleosynthesis and Electromagnetic Signatures of Dynamical Ejecta

Fast neutron-rich material ejected dynamically over ≲10 ms during the merger of a binary neutron star (BNS) can give rise to distinctive electromagnetic counterparts to the system's gravitational-wave emission that serve as a "smoking gun" to distinguish between a BNS and an NS-black hole merger. We present novel ab initio modeling of the kilonova precursor and kilonova afterglow based on 3D general-relativistic magnetohydrodynamic simulations of BNS mergers with nuclear, tabulated, finite-temperature equations of state (EOSs), weak interactions, and approximate neutrino transport. We analyze dynamical mass ejection from 1.35-1.35 M ⊙ binaries, consistent with properties of the first observed BNS merger GW170817, using three nuclear EOSs that span the range of allowed compactness of 1.35 M ⊙-neutron stars. Nuclear reaction network calculations yield a robust second-to-third-peak r-process. We find few ×10-6 M ⊙ of fast (v > 0.6c) ejecta that give rise to broadband synchrotron emission on ~years timescales, consistent with tentative evidence for excess X-ray/radio emission following GW170817. We find ≈2 × 10-5 M ⊙ of free neutrons that power a kilonova precursor on ≲ hours timescale. A boost in early UV/optical brightness by a factor of a few due to previously neglected relativistic effects, with enhancements up to ≲10 hr post-merger, is promising for future detection with UV/optical telescopes like Swift or ULTRASAT. We find that a recently predicted opacity boost due to highly ionized lanthanides at ≳70,000 K is unlikely to affect the early kilonova based on the obtained ejecta structures. Azimuthal inhomogeneities in dynamical ejecta composition for soft EOSs found here ("lanthanide/actinide pockets") may have observable consequences for both early kilonova and late-time nebular emission.

Keywords: gravitational wave astronomy; neutron stars; magnetohydrodynamical simulations; compact binary stars
The Age of Discovery with the James Webb Space Telescope: Excavating the Spectral Signatures of the First Massive Black Holes

The James Webb Space Telescope (JWST) will open a new window into the most distant universe and unveil the early growth of supermassive black holes (BHs) in the first galaxies. In preparation for deep JWST imaging surveys, it is crucial to understand the color selection of high-redshift accreting seed BHs. We model the spectral energy distribution of super-Eddington accreting BHs with millions of solar masses in metal-poor galaxies at z ≳ 8, applying postprocess line transfer calculations to radiation hydrodynamical simulation results. Exposures of 10 ks with the NIRCam and MIRI broadband filters are sufficient to detect the radiation flux from the seed BHs with bolometric luminosities of L bol ≃ 1045 erg s-1. While the continuum colors are similar to those of typical low-z quasars, strong Hα line emission with a rest-frame equivalent width EWrest ≃ 1300 Å is so prominent that the line flux affects the broadband colors significantly. The unique colors, for instance, F356W - F560W ≳ 1 at 7 < z < 8 and F444W - F770W ≳ 1 at 9 < z < 12, provide robust criteria for photometric selection of rapidly growing seed BHs. Moreover, NIRSpec observations of low-ionization emission lines can test whether the BH is fed via a dense accretion disk at super-Eddington rates.

Keywords: supermassive black holes; quasars; high-redshift galaxies
A GMOS/IFU Study of Jellyfish Galaxies in Massive Clusters

Jellyfish galaxies are an intriguing snapshot of galaxies undergoing ram pressure stripping (RPS) in dense environments, showing spectacular star-forming knots in their disks and tails. We study the ionized gas properties of five jellyfish galaxies in massive clusters with Gemini GMOS/Integral Field Unit observations: MACSJ0916-JFG1 (z = 0.330), MACSJ1752-JFG2 (z = 0.353), A2744-F0083 (z = 0.303), MACSJ1258-JFG1 (z = 0.342), and MACSJ1720-JFG1 (z = 0.383). "Baldwin, Phillips, and Terlevich" diagrams show that star formation, active galactic nuclei (AGNs), or mixed effects are ionizing gas in these galaxies. Radial velocity distributions of ionized gas seem to follow disk rotation of galaxies, with the appearance of a few high-velocity components in the tails as a sign of RPS. Mean gas velocity dispersion is lower than 50 km s-1 in most star-forming regions except near AGNs or shock-heated regions, indicating that the ionized gas is dynamically cold. Integrated star formation rates (SFRs) of these galaxies range from 7 M ⊙ yr-1 to 35 M ⊙ yr-1, and the tail SFRs are from 0.6 M ⊙ yr-1 to 16 M ⊙ yr-1, which are much higher than those of other jellyfish galaxies in the local universe. These high SFR values imply that RPS triggers intense star formation activity in these extreme jellyfish galaxies. The phase-space diagrams demonstrate that the jellyfish galaxies with higher stellar masses and higher host cluster velocity dispersion are likely to have more enhanced star formation activity. The jellyfish galaxies in this study have similar gas kinematics and dynamical states to those in the local universe, but they show a much higher SFR.

Keywords: galaxy environments; galaxy clusters; ram pressure stripped tails; intracluster medium; starburst galaxies; galaxy spectroscopy
Confining Burst Energy Function and Spectral Fringe Pattern of FRB 20121102A with Multifrequency Observations

The observed spectral shapes variation and tentative bimodal burst energy distribution (E-distribution) of fast radio burst (FRB) 20121102A with the FAST telescope are great puzzles. Adopting the published multifrequency data observed with the FAST and Arecibo telescopes at L band and the Green Bank Telescope (GBT) at C band, we investigate these puzzles through Monte Carlo simulations. The intrinsic energy function (E-function) is modeled as ${dp}/{dE}\propto {E}^{-{\alpha }_{{\rm{E}}}}$ , and the spectral profile is described as a Gaussian function. A fringe pattern of its spectral peak frequency (ν p ) in 0.5-8 GHz is inferred from the ν p distribution of the GBT sample. We estimate the likelihood of α E and the standard deviation of the spectral profile (σ s) by utilizing the Kolmogorov-Smirnov test probability for the observed and simulated specific E-distributions. Our simulations yield ${\alpha }_{{\rm{E}}}={1.82}_{-0.30}^{+0.10}$ , and ${\sigma }_{{\rm{s}}}={0.18}_{-0.06}^{+0.28}$ (3σ confidence level) with the FAST sample. These results suggest that a single power-law function is adequate to model the E-function of FRB 20121102A. The variations of its observed spectral indices and E-distributions with telescopes in different frequency ranges are due to both physical and observational reasons, i.e., narrow spectral width for a single burst and discrete ν p fringe pattern in a broad frequency range among bursts, and the selection effects of the telescope bandpass and sensitivity. The putative ν p fringe pattern cannot be explained with the current radiation physics models of FRBs. Some caveats of possible artificial effects that may introduce such a feature are discussed.

Keywords: radio transient sources
Increasing the Usability and Accessibility of Voyager 2 Images of Triton

Much of what we know about Neptune's moon Triton was inferred from the analysis of images returned by the Voyager 2 mission, the only spacecraft to have visited that putative ocean world. Unfortunately, the highest-resolution images (scales < 2 km pixel‑1) are difficult to use because they are only available in nonstandard formats, and the locations of the images on Triton's surface are incorrect by up to 200 km. Although image mosaics of Triton are publicly available, these do not include the highest-resolution data. Here we describe our effort to improve the usability and accessibility of Voyager 2 images of Triton. We used the USGS's ISIS software to process 41 Triton images, including geometric calibration, radiometric calibration, and reseau removal. We improved the image locations using a photogrammetric control network with 958 points and 3910 image measurements. Least-squares bundle adjustment of the network yielded rms uncertainty of 0.50, 0.52, and 0.51 pixels in latitude, longitude, and radius, respectively, and maximum residuals of ‑4.21 and +3.20 pixels, respectively. Image-to-image alignment is therefore vastly improved. We have released these processed images as cloud-optimized GeoTIFFs in orthographic projection at the original pixel scale of each image. Associated mosaics have also been created and released to provide geologic context for the individual images. These products provide the science community with analysis-ready data that enable new investigations of Triton, increase accessibility to this unique data set, and continue to enhance the scientific return from the Voyager 2 mission.

Keywords: triton; photogrammetry
Understanding the Kinetic Energy Deposition within Molecular Clouds

According to the structures traced by 13CO spectral lines within 12CO molecular clouds (MCs), we investigate the contributions of their internal gas motions and relative motions to the total velocity dispersions of 12CO MCs. Our samples of 2851 12CO MCs harbor a total of 9556 individual 13CO structures, among which 1848 MCs (~65%) have one individual 13CO structure and the other 1003 MCs (~35%) have multiple 13CO structures. We find that the contribution of the relative motion between 13CO structures ( ${\sigma }_{{}^{13}\mathrm{CO},\mathrm{re}}$ ) is larger than that from their internal gas motion ( ${\sigma }_{{}^{13}\mathrm{CO},\mathrm{in}}$ ) in ~62% of 1003 MCs in the "Multiple" regime. In addition, we find that ${\sigma }_{{}^{13}\mathrm{CO},\mathrm{re}}$ tends to increase with the total velocity dispersion ( ${\sigma }_{{}^{12}\mathrm{CO},\mathrm{tot}}$ ) in our samples, especially for MCs with multiple 13CO structures. This result provides a manifestation of macroturbulence within MCs, which gradually becomes the dominant way of storing kinetic energy along with the development of MC scales.

Keywords: interstellar medium; molecular clouds
Quenching, Mergers, and Age Profiles for z = 2 Galaxies in IllustrisTNG

Using the IllustrisTNG cosmological galaxy formation simulations, we analyze the physical properties of young quiescent galaxies at z = 2 with stellar masses above 1010.5 M⊙. This key population provides an unaltered probe into the evolution of galaxies from star-forming to quiescent, and has been recently targeted by several observational studies. Young quiescent galaxies in the simulations do not appear unusually compact, in tension with observations, but they show unique age profiles that are qualitatively consistent with the observed color gradients. In particular, more than half of the simulated young quiescent galaxies show positive age gradients due to recent intense central starbursts, which are triggered by significant mergers. Yet, there is a sizable population of recently quenched galaxies without significant mergers and with flat age profiles. Our results suggest that mergers play a fundamental role in structural transformation, but are not the only available pathway to quench a z = 2 galaxy.

Keywords: galaxy quenching; post-starburst galaxies; galaxy structure; astronomical simulations
Low- and High-velocity O VI in Milky Way-like Galaxies: The Role of Stellar Feedback

Milky Way-type galaxies are surrounded by a warm-hot gaseous halo containing a considerable amount of baryons and metals. The kinematics and spatial distribution of highly ionized ion species such as O VI can be significantly affected by supernova (SN) explosions and early (pre-SN) stellar feedback (e.g., stellar winds, radiation pressure). Here we investigate effects of stellar feedback on O VI absorptions in Milky Way‑like galaxies by analyzing the suites of high-resolution hydrodynamical simulations under the framework of SMUGGLE, a physically motivated subgrid interstellar medium and stellar feedback model for the moving-mesh code AREPO. We find that the fiducial run with the full suite of stellar feedback and moderate star formation activities can reasonably reproduce Galactic O VI absorptions observed by space telescopes such as the Far-Ultraviolet Spectroscopic Explorer, including the scale height of low-velocity (∣v LSR∣ < 100 km s‑1) O VI, the column density–line width relation for high-velocity (100 km s‑1 ≤ ∣v LSR∣ < 400 km s‑1) O VI, and the cumulative O VI column densities. In contrast, model variations with more intense star formation activities deviate from observations further. Additionally, we find that the run considering only SN feedback is in broad agreement with the observations, whereas in runs without SN feedback this agreement is absent, which indicates a dominant role of SN feedback in heating and accelerating interstellar O VI. This is consistent with the current picture that interstellar O VI is predominantly produced by collisional ionization where mechanical feedback can play a central role. In contrast, photoionization is negligible for O VI production owing to the lack of high-energy (≳114 eV) photons required.

Keywords: high-velocity clouds; interstellar medium; warm ionized medium; circumgalactic medium; ultraviolet spectroscopy
Extreme High-velocity Outflows from High-redshift BOSS Quasars

It is common to assume that all narrow absorption lines (NALs) at extreme high-velocity shifts form in cosmologically intervening gas or galaxies unrelated to quasars. However, previous detailed studies of individual quasars have shown that some NALs at these large velocity shifts do form in high-speed quasar ejecta. We search for extreme high-velocity NAL outflows (with speeds ∼0.1c-0.2c) based on relationships with associated absorption lines (AALs) and broad absorption-line (BAL) outflows. We find that high-velocity NALs are strongly correlated with AALs, BALs, and radio loudness, indicating that a significant fraction of high-velocity systems are either ejected from the quasars or form in material swept up by the radio jets (and are not unrelated intervening gas). We also consider line-locked C IV doublets as another indicator of high-velocity NALs formed in outflows. The fact that line-locked NALs are highly ionized and correlated with BAL outflows and radio-loud quasars implies that physical line locking due to radiative forces is both common and real, which provides indirect evidence that a significant fraction of high-velocity NALs are intrinsic to quasars.

Keywords: quasars; quasar absorption line spectroscopy
Long-term Protoplanetary Disk Evolution from Molecular Cloud Core Collapse and Implications for Planet Formation. I. Weak and Moderate Disk Self-gravities

We construct a one-dimensional protoplanetary disk model to investigate long-term disk evolution from molecular cloud core collapse. To obtain details of disk evolution, instead of solving the traditional diffusion equation for disk surface density, we suggest a set of equations derived from the basic principles of fluid mechanics. Effects of infalling material, magnetorotational instability, and disk self-gravity are taken into account. According to the role of disk self-gravity, we find that disks can be classified into three types. For a type I disk, disk self-gravity is not important. For a type II disk, disk self-gravity has effects on both disk scale height and gas radial motion. In addition, gravitational instability can cause the transport of angular momentum. For a type III disk, disk self-gravity plays a dominant role in disk evolution. In this paper, we focus on the first two types and the investigation of the third one is presented in a companion paper. For each disk, we find that there are three phases during evolution. Phase 1 is the very early phase during which the radial velocity is on the order of 106 cm s-1 and the transport of angular momentum caused by viscosity is not important. Phase 2 begins when a rotationally supported disk is formed. From this phase, viscosity plays a role in the transport of angular momentum. When the infall ends, phase 3 begins. Since angular velocity is calculated directly, we can reveal the non-Keplerian effect, which has important effects on the radial drift of solids and planetesimal formation.

Keywords: protoplanetary disks; planet formation; exoplanet formation
H I, FRB, What's Your z: The First FRB Host Galaxy Redshift from Radio Observations

Identification and follow-up observations of the host galaxies of fast radio bursts (FRBs) not only help us understand the environments in which the FRB progenitors reside, but also provide a unique way of probing the cosmological parameters using the dispersion measures (DMs) of FRBs and distances to their origin. A fundamental requirement is an accurate distance measurement to the FRB host galaxy, but for some sources viewed through the Galactic plane, optical/near-infrared spectroscopic redshifts are extremely difficult to obtain due to dust extinction. Here we report the first radio-based spectroscopic redshift measurement for an FRB host galaxy, through detection of its neutral hydrogen (H I) 21 cm emission using MeerKAT observations. We obtain an H I–based redshift of z = 0.0357 ± 0.0001 for the host galaxy of FRB 20230718A, an apparently nonrepeating FRB detected in the Commensal Real-time ASKAP Fast Transients survey and localized at a Galactic latitude of –0.°367. Our observations also reveal that the FRB host galaxy is interacting with a nearby companion, which is evident from the detection of an H I bridge connecting the two galaxies. A subsequent optical spectroscopic observation confirmed an FRB host galaxy redshift of 0.0359 ± 0.0004. This result demonstrates the value of H I to obtain redshifts of FRBs at low Galactic latitudes and redshifts. Such nearby FRBs whose DMs are dominated by the Milky Way can be used to characterize these components and thus better calibrate the remaining cosmological contribution to dispersion for more distant FRBs that provide a strong lever arm to examine the Macquart relation between cosmological DM and redshift.

Keywords: h i line emission; radio transient sources
Anisotropy of Magnetic Field Spectra at Kinetic Scales of Solar Wind Turbulence as Revealed by the Parker Solar Probe in the Inner Heliosphere

Using the Parker Solar Probe data taken in the inner heliosphere, we investigate the power and spatial anisotropy of magnetic field spectra at kinetic scales (i.e., around sub-ion scales) in solar wind turbulence in the inner heliosphere. We find that strong anisotropy of the magnetic spectra occurs at kinetic scales with the strongest power in the perpendicular direction with respect to the local magnetic field (forming an angle θ B with the mean flow velocity). The spectral index of the magnetic spectra varies from -3.2 to -5.8 when the angle θ B changes from 90° to 180° (or 0°), indicating that strong anisotropy of the spectral indices occurs at kinetic scales in the solar wind turbulence. Using a diagnosis based on the magnetic helicity, we show that the anisotropy of the spectral indices can be explained by the nature of the plasma modes that carry the cascade at kinetic scales. We discuss our findings in light of existing theories and current development in the field.

Keywords: solar wind; interplanetary turbulence; heliosphere; space plasmas