adsabs/SciX_UAT_keywords huggingface dataset:
JWST Census for the Mass-Metallicity Star Formation Relations at z = 4-10 with Self-consistent Flux Calibration and Proper Metallicity Calibrators

We present the evolution of the mass-metallicity (MZ) relation at z = 4-10 derived with 135 galaxies identified in JWST/NIRSpec data taken from the three major public spectroscopy programs of ERO, GLASS, and CEERS. Because there are many discrepancies between the flux measurements reported by the early ERO studies, we first establish our NIRSpec data reduction procedure for reliable emission-line flux measurements and errors, successfully explaining Balmer decrements with no statistical tensions thorough comparisons with the early ERO studies. Applying the reduction procedure to the 135 galaxies, we obtain emission-line fluxes for physical property measurements. We confirm that 10 out of the 135 galaxies with [O III] λ4363 lines have electron temperatures of ≃(1.1-2.3) × 104 K, similar to lower-z star-forming galaxies, which can be explained by heating by young massive stars. We derive the metallicities of the 10 galaxies by a direct method and the rest of the galaxies with strong lines using the metallicity calibrations of Nakajima et al. applicable for these low-mass metal-poor galaxies, anchoring the metallicities with the direct-method measurements. We thus obtain the MZ relation and star formation rate (SFR)-MZ relation over z = 4-10. We find that there is a small evolution of the MZ relation from z ~ 2-3 to z = 4-10, while interestingly the SFR-MZ relation shows no evolution up to z ~ 8 but a significant decrease at z > 8 beyond the errors This SFR-MZ relation decrease at z > 8 may suggest a break of the metallicity equilibrium state via star formation, inflow, and outflow, while further statistical and local-baseline studies are needed for a conclusion.

Keywords: chemical abundances; galaxy chemical evolution; galaxy evolution; james webb space telescope; high-redshift galaxies
Distribution and Kinematics of H I through Raman He II Spectroscopy of NGC 6302

The young planetary nebula NGC 6302 is known to exhibit Raman-scattered He II features at 6545 Å and 4851 Å. These features are formed through inelastic scattering of He II λλ 1025 and 972 with hydrogen atoms in the ground state, for which the cross sections are 1.2 × 10-21 cm2 and 1.4 × 10-22 cm2, respectively. We investigate the spectrum of NGC 6302 archived in the ESO Science Portal. Our Gaussian line-fitting analysis shows that the Raman-scattered He II features are broader and more redshifted than the hypothetical model Raman features that would be formed in a cold static H I medium. We adopt a simple scattering geometry consisting of a compact He II emission region surrounded by an H I medium to perform Monte Carlo simulations using the radiative transfer code STaRS. Our simulations show that the H I region is characterized by the H I column density N H I = 3 × 1021 cm-2, with the random speed component v ran = 10 km s-1 expanding with a speed ${v}_{\exp }=13\,\mathrm{km}\ {{\rm{s}}}^{-1}$ from the He II emission region. Based on our best-fit parameters, we estimate the H I mass of the neutral medium M H I ≃ 1.0 × 10-2 M ⊙, pointing out the usefulness of Raman He II spectroscopy as a tool to trace H I components.

Keywords: radiative transfer; radiative transfer simulations; planetary nebulae; high resolution spectroscopy
Electromagnetic Signatures of Relativistic Explosions in the Disks of Active Galactic Nuclei

The disks of active galactic nuclei (AGNs), traditionally studied as feeders of the supermassive black holes (SMBHs) at their centers, are also hosts to massive stars and hence their neutron star (NS) and black hole (BH) remnants. Migration traps and gas torques in these disks favor binary formation and enhance the rate of compact object mergers. In these environments both long gamma-ray bursts (GRBs) from the death of massive stars and short GRBs from NS-NS to NS-BH mergers are expected. However, their properties in the environment of AGN disks have never been studied. Here we show that GRBs in AGN disks can display unique features, owing to the unusual relative position of the shocks that characterize the burst evolution and the Thomson photosphere of the AGN disk. In dense environments, for example, a relativistic reverse shock develops early, likely powering the prompt emission instead of internal shocks. The transient's time evolution is also compressed, yielding afterglow emission that is brighter and may peak earlier than for GRBs in the interstellar medium. Additionally, in regions of the disk that are sufficiently dense and extended, the light curves are dominated by diffusion, since the fireball remains inside the disk photosphere throughout the entire evolution. These diffusion-dominated transients emerge on timescales of days in disks around SMBHs of ∼ 106M⊙ to years for SMBHs of ∼ 108M⊙. Finally, a large fraction of events, especially in AGNs with SMBHs ≲ 107M⊙, display time-variable absorption in the X-ray band.

Keywords: active galactic nuclei; gamma-ray bursts; relativistic jets
Angular Expansion of Nova Shells

Nova shells can provide important information on their distance, their interactions with circumstellar and interstellar media, and the evolution in morphology of the ejecta. We have obtained narrowband images of a sample of five nova shells, namely DQ Her, FH Ser, T Aur, V476 Cyg, and V533 Her, with ages ranging from 50 to 130 yr. These images have been compared with suitable available archival images to derive their angular expansion rates. We find that all the nova shells in our sample are still in the free expansion phase, which can be expected, as the mass of the ejecta is 7-45 times larger than the mass of the swept-up circumstellar medium. The nova shells will keep expanding freely for time periods up to a few hundred years, reducing their time dispersal into the interstellar medium.

Keywords: cataclysmic variable stars; interstellar medium; astronomical techniques
XMM Observation of the Supernova Remnant J0454-6713 and the Adjacent N9 Superbubble

The Large Magellanic Cloud supernova remnant J0454-6713 abutting the H II region N9 has been observed with XMM-Newton. Two groups of lines from Fe XVII account for half the emission and lines from Fe XVIII, O VII, and O VIII are also clearly detected with the XMM RGS. Isothermal equilibrium fits of the EPIC spectra reproduce the basic spectral form and show little variation throughout the remnant but are insensitive to the lines from the high-temperature ions. These are overwhelmed in the EPIC cameras by the dominant Fe XVII radiation and the EPIC best-fit spectra do not agree with the RGS data. Uncertainties in the atomic data used to determine Fe-line strength present a further complication which inhibits a good EPIC spectral fit. We build a two-temperature model which does fit both RGS and EPIC results and propose that the high-T component is from SN debris and the low from heated material in the H II region. The high ratio of Fe emission to that from O requires the remnant to be the product of a Type Ia supernova and points to a deflagration-detonation origin. Weak X-ray emission from the N9 superbubble is detected and briefly discussed. The abundance of Ne in N9 material seems higher than average for the LMC in both the superbubble spectrum and the low-temperature component of the remnant RGS spectrum.

Keywords: supernova remnants; large magellanic cloud; x-ray astronomy; plasma astrophysics; type ia supernovae
Modeling the Photometric Variability of Alpha2 CVn with a Dynamical Magnetosphere

Alpha2 Canum Venaticorum (α 2 CVn) is a strongly magnetic star with peculiar chemical signatures and periodic variability that have been long attributed to the diffusion of magnetic elements through the photosphere, leading to chemical spots across the stellar surface. However, recent studies of other magnetic hot stars are consistent with magnetospheric clouds above the surface. Here we take a renewed approach to modeling α 2 CVn with a simplified dynamical magnetosphere and a tilted, offset magnetic dipole to reproduce its Transiting Exoplanet Survey Satellite variability. Our dipole model also reproduces well the magnetic surface map of α 2 CVn from Silvester et al. Its ultraviolet variability, from IUE archival spectra, is also consistent with traditional reddening models. However, other observable quantities from the system contradict the expectations of a magnetosphere, and we conclude that it is unlikely to be present in α 2 CVn.

Keywords: magnetic stars
On the Investigation of the Closure Relations for Gamma-Ray Bursts Observed by Swift in the Post-plateau Phase and the GRB Fundamental Plane

Gamma-ray Bursts (GRBs) are the most explosive phenomena in the universe after the big bang. A large fraction of GRB lightcurves (LCs) shows X-ray plateaus. We perform the most comprehensive analysis of all GRBs (with known and unknown redshifts) with plateau emission observed by The Neil Gehrels Swift Observatory from its launch until 2019 August. We fit 455 LCs showing a plateau and explore whether these LCs follow closure relations, relations between the temporal and spectral indices of the afterglow, corresponding to two distinct astrophysical environments and cooling regimes within the external forward shock (ES) model, and find that the ES model works for the majority of cases. The most favored environments are a constant-density interstellar or wind medium with slow cooling. We also confirm the existence of the fundamental plane relation between the rest-frame time and luminosity at the end of the plateau emission and the peak prompt luminosity for this enlarged sample, and test this relation on groups corresponding to the astrophysical environments of our known redshift sample. The plane becomes a crucial discriminant corresponding to these environments in terms of the best-fitting parameters and dispersions. Most GRBs for which the closure relations are fulfilled with respect to astrophysical environments have an intrinsic scatter σ compatible within 1σ of that of the "Gold" GRBs, a subset of long GRBs with relatively flat plateaus. We also find that GRBs satisfying closure relations indicating a fast cooling regime have a lower σ than ever previously found in literature.

Keywords: gamma-ray bursts
Solar Polar Magnetic Fields: Comparing Full-disk and High-resolution Spectromagnetograph Data

This is the first systematic comparison between photospheric polar magnetic field data from a full-disk synoptic observing program, the National Solar Observatory's Synoptic Optical Long-term Investigations of the Sun Vector Spectromagnetograph (SOLIS/VSM), and a high-resolution vector spectromagnetograph, the Hinode Solar Optical Telescope Spectropolarimeter (SOT/SP). Polar magnetic fluxes derived from longitudinal magnetic field measurements from both telescopes and from SOT/SP full-Stokes vector data are all compared in the form of polar synoptic maps. Measurements taken over 35 day periods with advantageous rotation axis tilt angle are used; observations extend to the poles, and no synthetic pole-filling is needed. Polar fluxes are derived from longitudinal data assuming an approximately radial field, whereas those derived from vector data are based on measured vector magnitude and direction. However, the full-vector measurements may have a detection problem: polar fields are observed as mostly transverse from (near) Earth, and Zeeman sensitivity to transverse fields is significantly lower than for longitudinal fields. Accordingly, the SOT/SP vector-based polar fluxes are lower than the longitudinal-based fluxes from both telescopes, a result driven by pixels without sufficient Q and U signals for the full-Stokes inversions to detect significant radial field but with good Stokes V signal implying a significant field. Furthermore, the SOT/SP longitudinal-based fluxes are significantly higher than their VSM counterparts because of superior seeing-free spatial resolution and longer observation time. The SOT/SP longitudinal-based polar fluxes appear large enough to account for radial interplanetary field measurements whereas the SOT/SP vector-based and the VSM ones are generally too low.

Keywords: quiet sun; solar cycle; solar magnetic fields; heliosphere
Photometric Analyses of Saturn's Small Moons: Aegaeon, Methone, and Pallene Are Dark; Helene and Calypso Are Bright

We examine the surface brightnesses of Saturn's smaller satellites using a photometric model that explicitly accounts for their elongated shapes and thus facilitates comparisons among different moons. Analyses of Cassini imaging data with this model reveal that the moons Aegaeon, Methone, and Pallene are darker than one would expect given trends previously observed among the nearby mid-sized satellites. On the other hand, the trojan moons Calypso and Helene have substantially brighter surfaces than their co-orbital companions Tethys and Dione. These observations are inconsistent with the moons' surface brightnesses being entirely controlled by the local flux of E-ring particles, and therefore strongly imply that other phenomena are affecting their surface properties. The darkness of Aegaeon, Methone, and Pallene is correlated with the fluxes of high-energy protons, implying that high-energy radiation is responsible for darkening these small moons. Meanwhile, Prometheus and Pandora appear to be brightened by their interactions with the nearby dusty F ring, implying that enhanced dust fluxes are most likely responsible for Calypso's and Helene's excess brightness. However, there are no obvious structures in the E ring that would preferentially brighten these two moons, so there must either be something subtle in the E-ring particles' orbital properties that leads to asymmetries in the relevant fluxes, or something happened recently to temporarily increase these moons' brightnesses.

Keywords: saturnian satellites; natural satellites (solar system); photometry; surface photometry; planetary magnetospheres; planetary rings
Introducing TIGRESS-NCR. I. Coregulation of the Multiphase Interstellar Medium and Star Formation Rates

Massive, young stars are the main source of energy that maintains multiphase structure and turbulence in the interstellar medium (ISM), and without this "feedback" the star formation rate (SFR) would be much higher than is observed. Rapid energy loss in the ISM and efficient energy recovery by stellar feedback lead to coregulation of SFRs and the ISM state. Realistic approaches to this problem should solve for the dynamical evolution of the ISM, including star formation and the input of feedback energy self-consistently and accurately. Here, we present the TIGRESS-NCR numerical framework, in which UV radiation, supernovae, cooling and heating processes, and gravitational collapse are modeled explicitly. We use an adaptive ray-tracing method for UV radiation transfer from star clusters represented by sink particles, accounting for attenuation by dust and gas. We solve photon-driven chemical equations to determine the abundances of hydrogen (time dependent) and carbon/oxygen-bearing species (steady state), which then set cooling and heating rates self-consistently. Applying these methods, we present high-resolution magnetohydrodynamics simulations of differentially rotating local galactic disks representing typical conditions of nearby star-forming galaxies. We analyze ISM properties and phase distributions and show good agreement with existing multiwavelength galactic observations. We measure midplane pressure components (turbulent, thermal, and magnetic) and the weight, demonstrating that vertical dynamical equilibrium holds. We quantify the ratios of pressure components to the SFR surface density, which we call the feedback yields. The TIGRESS-NCR framework will allow for a wide range of parameter exploration, including in low-metallicity systems.

Keywords: interstellar medium; star formation; stellar feedback; magnetohydrodynamical simulations; radiative transfer simulations
Modified Temperature–Redshift Relation and Ultra-high-energy Cosmic Ray Propagation

We reexamine the interactions of ultra-high-energy cosmic rays (UHECRs) with photons from the cosmic microwave background (CMB) under a changed, locally nonlinear temperature–redshift relation T(z). This changed temperature–redshift relation has recently been suggested by the postulate of subjecting thermalized and isotropic photon gases such as the CMB to an SU(2) rather than a U(1) gauge group. This modification of ΛCDM is called SU(2)CMB, and some cosmological parameters obtained by SU(2)CMB seem to be in better agreement with local measurements of the same quantities, in particular H 0 and S8. In this work, we apply the reduced CMB photon density under SU(2)CMB to the propagation of UHECRs. This leads to a higher UHECR flux just below the ankle in the cosmic ray spectrum and slightly more cosmogenic neutrinos under otherwise equal conditions for emission and propagation. Most prominently, the proton flux is significantly increased below the ankle (5 × 1018 eV) for hard injection spectra and without considering the effects of magnetic fields. The reduction in CMB photon density also favors a decreased cosmic ray source evolution than the best fit using ΛCDM. In consequence, it seems that SU(2)CMB favors sources that evolve like the star formation rate, such as starburst galaxies and gamma-ray bursts, over active galactic nuclei as origins of UHECRs. We conclude that the question about the nature of primary sources of UHECRs is directly affected by the assumed temperature–redshift relation of the CMB.

Keywords: ultra-high-energy cosmic radiation; cosmological neutrinos; cosmology
Using Maximum Circular Velocity in Halo Occupation Distribution Models to Predict Galaxy Clustering

Standard halo occupation distribution (HOD) models predict how galaxies occupy halos based on a single property, the virial mass, M vir. To incorporate galaxy assembly bias, we consider alternative halo mass proxies to use in the HOD. A promising replacement is maximum circular velocity, ${V}_{\max }$ , which measures the halo's potential well, and successfully predicts galaxy clustering in subhalo abundance matching models. We fit galaxy clustering measurements from SDSS DR7 with two modified HODs besides the standard M vir-based model: one where ${V}_{\max }$ is used as the halo property that determines galaxy occupation, and the other adopting an adjustable combination of M vir and ${V}_{\max }$ . Except for the reduced volume M r < - 20 threshold sample fit with ${V}_{\max }$ alone, neither change improves the model performance in predicting the projected two-point correlation function, w p. We conclude that switching the primary variable to ${V}_{\max }$ does not significantly improve the HOD model's ability to fit galaxy clustering.

Keywords: galaxy dark matter halos; galaxy formation; galaxy evolution; astronomical models
Measurement of Dependence of Microlensing Planet Frequency on the Host Star Mass and Galactocentric Distance by Using a Galactic Model

We measure the dependence of planet frequency on host star mass, M L, and distance from the Galactic center, R L, using a sample of planets discovered by gravitational microlensing. We compare the two-dimensional distribution of the lens-source proper motion, μ rel, and the Einstein radius crossing time, t E, measured for 22 planetary events from Suzuki et al. with the distribution expected from Galactic model. Assuming that the planet-hosting probability of a star is proportional to ${M}_{{\rm{L}}}^{m}{R}_{{\rm{L}}}^{r}$ , we calculate the likelihood distribution of (m,r). We estimate that $r={0.10}_{-0.37}^{+0.51}$ and $m={0.50}_{-0.70}^{+0.90}$ under the assumption that the planet-hosting probability is independent of the mass ratio. We also divide the planet sample into subsamples based on their mass ratio, q, and estimate that $m=-{0.08}_{-0.65}^{+0.95}$ for q < 10‑3 and ${1.25}_{-1.14}^{+1.07}$ for q > 10‑3. Although uncertainties are still large, this result implies a possibility that, in orbits beyond the snowline, massive planets are more likely to exist around more massive stars whereas low-mass planets exist regardless of their host star mass.

Keywords: planet formation; exoplanets; gravitational microlensing
Tracing the Magnetic Field Topology of the Quiet Corona Using Propagating Disturbances

The motion of faint propagating disturbances (PDs) in the solar corona reveals an intricate structure that must be defined by the magnetic field. Applied to quiet Sun observations by the Atmospheric Imaging Assembly (AIA)/Solar Dynamics Observatory (SDO), a novel method reveals a cellular network, with cells of typical diameters 50″ in the cool 304 Å channel and 100″ in the coronal 193 Å channel. The 193 Å cells can overlie several 304 Å cells, although both channels share common source and sink regions. The sources are points, or narrow corridors, of divergence that occupy the centers of cells. They are significantly aligned with photospheric network features and enhanced magnetic elements. This shows that the bright network is important to the production of PDs and confirms that the network is host to the source footpoint of quiet coronal loops. The other footpoint, or the sinks of the PDs, form the boundaries of the coronal cells. These are not significantly aligned with the photospheric network-they are generally situated above the dark internetwork photosphere. They form compact points or corridors, often without an obvious signature in the underlying photosphere. We argue that these sink points can either be concentrations of closed field footpoints associated with minor magnetic elements in the internetwork or concentrations of an upward-aligned open field. The link between the coronal velocity and magnetic fields is strengthened by comparison with a magnetic extrapolation, which shows several general and specific similarities, thus the velocity maps offer a valuable additional constraint on models.

Keywords: quiet solar corona; quiet solar chromosphere; solar magnetic fields; solar atmospheric motions
The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey

The spatial distribution and evolution of gas in the inner 10 au of protoplanetary disks form the basis for estimating the initial conditions of planet formation. Among the most important constraints derived from spectroscopic observations of the inner disk are the radial distributions of the major gas phase constituents, how the properties of the gas change with inner disk dust evolution, and how the chemical abundances and excitation conditions are influenced by the high-energy radiation from the central star. We present a survey of the radial distribution, excitation, and evolution of inner disk molecular hydrogen (H2) obtained as part of the Hubble Space Telescope-ULLYSES program. We analyze far-UV spectroscopy of 71 (63 accreting) pre-main-sequence systems in ULLYSES DR5 to characterize the H2 emission lines, H2 dissociation continuum emission, and major photochemical/disk evolution driving the UV emissions (Lyα, UV continuum, and C IV). We use the widths of the H2 emission lines to show that most fluorescent H2 arises between 0.1 and 1.4 au from the parent star, and show positive correlations of the average emitting radius with the accretion luminosity and with the dust disk mass. We find a strong correlation between H2 dissociation emission and both the accretion-dominated Lyα luminosity and the inner disk dust clearing, painting a picture where water molecules in the inner 3 au are exposed to and dissociated by strong Lyα emission as the opacity of the inner disk declines with time.

Keywords: protoplanetary disks; circumstellar gas; planet formation