adsabs/SciX_UAT_keywords huggingface dataset:
Probing the Nature of High-redshift Weak Emission Line Quasars: A Young Quasar with a Starburst Host Galaxy

We present the discovery of PSO J083.8371+11.8482, a weak emission line quasar with extreme star formation rate at z = 6.3401. This quasar was selected from Pan-STARRS1, UHS, and unWISE photometric data. Gemini/GNIRS spectroscopy follow-up indicates a Mg II-based black hole mass of ${M}_{\mathrm{BH}}=\left({2.0}_{-0.4}^{+0.7}\right)\times {10}^{9}$ M⊙ and an Eddington ratio of ${L}_{\mathrm{bol}}/{L}_{\mathrm{Edd}}={0.5}_{-0.2}^{+0.1}$ , in line with an actively accreting supermassive black hole (SMBH) at z ≳ 6. Hubble Space Telescope imaging sets strong constraint on lens boosting, showing no relevant effect on the apparent emission. The quasar is also observed as a pure point source with no additional emission component. The broad-line region (BLR) emission is intrinsically weak and not likely caused by an intervening absorber. We found rest-frame equivalent widths of EW ${(\mathrm{Ly}\alpha +{\rm{N}}{\rm\small{V}})}_{\mathrm{rest}}=5.7\pm 0.7\,\mathring{\rm A} $ , EW ${({\rm{C}}{\rm\small{IV}})}_{\mathrm{rest}}\leqslant 5.8$ Š(3σ upper limit), and EW ${(\mathrm{Mg}{\rm\small{II}})}_{\mathrm{rest}}=8.7\pm 0.7\,\mathring{\rm A} $ . A small proximity zone size ( ${R}_{{\rm{p}}}=1.2\pm 0.4$ pMpc) indicates a lifetime of only ${t}_{{\rm{Q}}}={10}^{3.4\pm 0.7}$ years from the last quasar phase ignition. ALMA shows extended [C II] emission with a mild velocity gradient. The inferred far-infrared luminosity ( ${L}_{\mathrm{FIR}}=(1.2\pm 0.1)\times {10}^{13}\,{L}_{\odot }$ ) is one of the highest among all known quasar hosts at z ≳ 6. Dust and [C II] emissions put a constraint on the star formation rate of SFR = 900- $4900\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$ , similar to that of a hyperluminous infrared galaxy. Considering the observed quasar lifetime and BLR formation timescale, the weak-line profile in the quasar spectrum is most likely caused by a BLR that is not yet fully formed rather than by continuum boosting by gravitational lensing or a soft continuum due to super-Eddington accretion.

Keywords: quasars; supermassive black holes; active galactic nuclei; agn host galaxies; intergalactic medium; reionization; early universe
Searching for Molecular Jets from High-mass Protostars

We report Very Large Array observations in the Q band toward 10 ionized jet candidates to search for SiO emission, a well-known shocked gas tracer. We detected 7 mm continuum counterparts toward 90% of the jet candidates. In most cases, the jet candidate is located toward the center of the 7 mm core, and the high masses (≈100 M ⊙) and densities (≈107 cm-3) of the cores suggest that the central objects are very young high-mass protostars. We detected SiO J = 1-0 emission associated with six target sources. In all cases, the morphology and spectrum of the emission is consistent with what is expected for molecular jets along an outflow axis, thus confirming the jet nature of 60% of our sample. Our data suggest a positive correlation between the SiO luminosity L SiO, and both the bolometric luminosity L Bol and the radio luminosity S ν d 2 of the driving sources.

Keywords: jets; radio jets; star formation; protostars; young stellar objects
A Photometric Analysis of the Relationship between the UV flux of Type Ia Supernovae and Host-galaxy Metallicity

The effect of progenitor metallicity on Type Ia supernovae (SNe Ia) has important cosmological implications due to the need for these standardizable candles to be compared across large spans of cosmic time in which the progenitor stars might have different properties. Theoretical models have come to different conclusions as to the wavelength range impacted by metallicity differences, leading to differing interpretations of the growing sample of UV observations. Recent work has claimed a correlation between the mid-UV flux of SNe Ia measured from Swift grism spectra and the gas-phase metallicities measured for their host galaxies. Here we examine UV photometry for the same objects. We find no significant correlations between the UV-optical colors (or UV/optical count rate ratios) of the SNe Ia and the host-galaxy properties of mass or metallicity. The lack of a significant correlation with host-galaxy metallicity implies that a physical difference other than progenitor metallicity dominates the UV flux differences. Understanding the existing observations requires improved theoretical models and a larger parameter space of physical differences.

Keywords: type ia supernovae; metallicity
TRIDENT: A Rapid 3D Radiative-transfer Model for Exoplanet Transmission Spectra

Transmission spectroscopy is one of the premier methods used to probe the temperature, composition, and cloud properties of exoplanet atmospheres. Recent studies have demonstrated that the multidimensional nature of exoplanet atmospheres-due to nonuniformities across the day-night transition and between the morning and evening terminators-can strongly influence transmission spectra. However, the computational demands of 3D radiative-transfer techniques have precluded their usage within atmospheric retrievals. Here we introduce TRIDENT, a new 3D radiative-transfer model which rapidly computes transmission spectra of exoplanet atmospheres with day-night, morning-evening, and vertical variations in temperature, chemical abundances, and cloud properties. We also derive a general equation for transmission spectra, accounting for 3D atmospheres, refraction, multiple scattering, ingress/egress, grazing transits, stellar heterogeneities, and nightside thermal emission. After introducing TRIDENT's linear-algebra-based approach to 3D radiative transfer, we propose new parametric prescriptions for 3D temperature and abundance profiles and 3D clouds. We show that multidimensional transmission spectra exhibit two significant observational signatures: (i) day-night composition gradients alter the relative amplitudes of absorption features; and (ii) morning-evening composition gradients distort the peak-to-wing contrast of absorption features. Finally, we demonstrate that these signatures of multidimensional atmospheres incur residuals >100 ppm compared to 1D models, rendering them potentially detectable with the James Webb Space Telescope. TRIDENT's rapid radiative transfer, coupled with parametric multidimensional atmospheres, unlocks the final barrier to 3D atmospheric retrievals.

Keywords: exoplanet atmospheres; exoplanet atmospheric composition; hot jupiters; transmission spectroscopy; spectroscopy; exoplanets; radiative transfer
No Longer Impossible: The Self-lensing Binary KIC 8145411 is a Triple

Five self-lensing binaries (SLBs) have been discovered with data from the Kepler mission. One of these systems is KIC 8145411, which was reported to host an extremely low mass (ELM; 0.2 M ⊙) white dwarf (WD) in a 456 days orbit with a solar-type companion. The system has been dubbed "impossible," because evolutionary models predict that ∼0.2 M ⊙ WDs should only be found in tight orbits (P orb ≲ days). In this work, we show that KIC 8145411 is in fact a hierarchical triple system: it contains a WD orbiting a solar-type star, with another solar-type star ∼700 au away. The wide companion was unresolved in the Kepler light curves, was just barely resolved in Gaia DR3, and is resolved beyond any doubt by high-resolution imaging. We show that the presence of this tertiary confounded previous mass measurements of the WD for two reason: it dilutes the amplitude of the self-lensing pulses, and it reduces the apparent radial velocity (RV) variability amplitude of the WD's companion due to line blending. By jointly fitting the system's light curves, RVs, and multi-band photometry using a model with two luminous stars, we obtain a revised WD mass of (0.53 ± 0.01)M ⊙. Both luminous stars are near the end of their main-sequence evolution. The WD is thus not an ELM WD, and the system does not suffer the previously proposed challenges to its formation history. Similar to the other SLBs and the population of astrometric WD binaries recently identified from Gaia data, KIC 8145411 has parameters in tension with standard expectations for formation through both stable and unstable mass transfer (MT). The system's properties are likely best understood as a result of unstable MT from an AGB star donor.

Keywords: white dwarf stars; multiple stars; light curves
Study of the Influence of the Solar Wind Energy on the Geomagnetic Activity for Space Weather Science

This paper addresses the investigation of the interaction of the solar wind energy with the Earth's magnetosphere, by studying its correlation with the disturbance storm time (Dst) index, a proxy of the geomagnetic activity. Some relevant parameters of the solar wind (the bulk speed and the z-component of the interplanetary magnetic field) are explored in the energy-Dst space. It results that (I) the solar wind energy and the geomagnetic activity are strictly related, with the coronal mass ejections representing the most energetic and geoeffective driver; (II) the slow solar wind has negligible effects on Earth regardless of its energy content, whereas high-speed streams may induce severe geomagnetic storming depending on the advected energy; and (III) while at low and mid energies, geomagnetic disturbances are induced provided the magnetic reconnection between the interplanetary and terrestrial magnetic fields occurs, high-energy solar wind plasma can impact Earth even without reconnecting with the geomagnetic field at the dayside magnetopause. The most significant result in the framework of space weather science resides in the observational evidence that the Earth's magnetosphere has a maximum response to the energetic content of the solar wind, which leads to the derivation of an empirical law allowing the proper forecast of the upper limit of the intensity of any geomagnetic disturbance on the basis of the solar wind energy derived in situ at the Lagrangian point L1.

Keywords: magnetohydrodynamics; heliosphere; solar wind; space weather; solar-terrestrial interactions
A λ 3 mm Line Survey toward the Circumstellar Envelope of the Carbon-rich AGB Star IRC+10216 (CW Leo)

We present an unbiased λ 3 mm spectral line survey (between 84.5 and 115.8 GHz), conducted by the Purple Mountain Observatory 13.7 m radio telescope, together with updated modeling results, toward the carbon-rich asymptotic giant branch star IRC+10216 (CW Leo). A total of 75 spectral lines (96 transitions) are detected, and identified to arise from 19 molecules: C2H, l-C3H, C4H, CN, C3N, HC3N, HC5N, HCN, HNC, CH3CN, MgNC, CO, c-C3H2, SiC2, SiO, SiS, CS, C2S, C3S, and their isotopologues. Among them, one molecular emission line (H13CCCN J = 13–12) is discovered in IRC+10216 for the first time. The excitation temperature, column density, and fractional abundance of the detected species are deduced by assuming they are in local thermodynamic equilibrium. In addition, the isotopic ratios of [12C]/[13C], [32S]/[34S], [28Si]/[29Si], and [12C34S]/[13C32S] are obtained and found to be consistent with previous studies. Finally, we summarize all of the 106 species detected in IRC+10216 to date with their observed and modeled column densities for the convenience of future studies.

Keywords: astrochemistry
Two Directly Imaged, Wide-orbit Giant Planets around the Young, Solar Analog TYC 8998-760-1

Even though tens of directly imaged companions have been discovered in the past decades, the number of directly confirmed multiplanet systems is still small. Dynamical analysis of these systems imposes important constraints on formation mechanisms of these wide-orbit companions. As part of the Young Suns Exoplanet Survey we report the detection of a second planetary-mass companion around the 17 Myr-old, solar-type star TYC 8998-760-1 that is located in the Lower Centaurus Crux subgroup of the Scorpius-Centaurus association. The companion has a projected physical separation of 320 au and several individual photometric measurements from 1.1 to 3.8 microns constrain a companion mass of 6 ± 1 MJup, which is equivalent to a mass ratio of q = 0.57 ± 0.10% with respect to the primary. With the previously detected 14 ± 3 MJup companion that is orbiting the primary at 160 au, TYC 8998-760-1 is the first directly imaged multiplanet system that is detected around a young, solar analog. We show that circular orbits are stable, but that mildly eccentric orbits for either/both components (e > 0.1) are chaotic on gigayear timescales, implying in situ formation or a very specific ejection by an unseen third companion. Due to the wide separations of the companions TYC 8998-760-1 is an excellent system for spectroscopic and photometric follow-up with space-based observatories such as the James Webb Space Telescope. * Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programs 099.C-0698(A), 0101.C-0341(A), 2103.C-5012(B), and 0104.C-0265(A).

Keywords: extrasolar gaseous giant planets; exoplanet astronomy; exoplanet detection methods; exoplanets; direct imaging
Volatility of Sodium in Carbonaceous Chondrites at Temperatures Consistent with Low-perihelion Asteroids

Solar system bodies with surface and subsurface volatiles will show observational evidence of activity when they reach a temperature where those volatiles change from solid to gas and are released. This is most frequently seen in comets, where activity is driven by the sublimation of water, carbon dioxide, or carbon monoxide ices. However, some bodies (notably the asteroid (3200) Phaethon) show initiation of activity at very small heliocentric distances, long after they have reached the sublimation temperatures of these ices. We investigate whether the sodium present in the mineral matrix could act as the volatile element responsible for this activity. We conduct theoretical modeling which indicates that sodium has the potential to sublimate in the conditions that Phaethon experiences, depending on the mineral phase it is held in. To test this, we then exposed samples of the carbonaceous chondrite Allende to varying heating events, similar to what would be experienced by low-perihelion asteroids. We measured the change in sodium present in each sample and find that the highest temperature samples show a significant loss of sodium from specific mineral phases over a single heating event, comparable to a day on the surface of Phaethon. Under specific thermal histories possible for Phaethon, this outgassing could be sufficient to explain this object's observed activity. This effect would also be expected to be observed for other low-perihelion asteroids as well and may act as a critical step in the process of disrupting small low-albedo asteroids.

Keywords: asteroids; near-earth objects; comet volatiles
Deconstructing the Planck TT Power Spectrum to Constrain Deviations from ΛCDM

Consistency checks of Lambda cold dark matter (ΛCDM) predictions with current cosmological data sets may illuminate the types of changes needed to resolve cosmological tensions. To this end, we modify the CLASS Boltzmann code to create phenomenological amplitudes, similar to the lensing amplitude parameter AL, for the Sachs-Wolfe, Doppler, early Integrated Sachs-Wolfe (eISW), and polarization contributions to the cosmic microwave background temperature anisotropy, and then we include these additional amplitudes in fits to the Planck TT power spectrum. We find that allowing one of these amplitudes to vary at a time results in little improvement over ΛCDM alone suggesting that each of these physical effects are being correctly accounted for given the current level of precision. Further, we find that the only pair of phenomenological amplitudes that results in a significant improvement to the fit to Planck temperature data results from varying the amplitudes of the Sachs-Wolfe and Doppler effects simultaneously. However, we show that this model is really just refinding the ΛCDM + AL solution. We test adding our phenomenological amplitudes as well as Neff, YHe, and nrun to ΛCDM + AL and find that none of these model extensions provide significant improvement over ΛCDM + AL when fitting Planck temperature data. Finally, we quantify the contributions of both the eISW effect and lensing on the constraint of the physical matter density from Planck temperature data by allowing the phenomenological amplitude from each effect to vary. We find that these effects play a relatively small role (the uncertainty increases by 3.5% and 16% respectively) suggesting that the overall photon envelope has the greatest constraining power.

Keywords: observational cosmology; cosmic microwave background radiation; cosmological parameters; hubble constant; cosmological models
Double Power-law Formation by Sequential Particle Acceleration

Spectral double power laws are common in solar high-energy phenomena such as flares and interplanetary energetic-electron events. However, the physical mechanism that produces the changes in power-law index within a single spectrum is unclear. We developed a fully analytical method of forming single power-law spectra from sequential acceleration of particles orbiting inside and hopping between simulated large-scale magnetic islands formed by flare reconnection. Here, we extend the analytical method to the formation of double power-law spectra by assuming sequential acceleration in two successive regions with different acceleration and particle-transport rates. The resulting spectral distribution is continuous and smooth, with a flattening at low energies, two power-law regions at mid-energies, and a steep rollover at high energies. The model provides analytical expressions for the spectral indices, all energy breaks, and normalization constants as functions of just three physical parameters of each acceleration region: (1) the energy gain in each accelerator, (2) the percentage of particles transferred between accelerators, and (3) the number of accelerators visited. One of the most salient predictions of our work is that the spectral index at high (low) energies is determined by the parameters of the first "seed" (second) acceleration region. By constructing the spectral distribution through an iterative analytical process, the evolution toward a double power law is easily characterized and explained. Our analytical model provides tools to interpret space- and ground-based observations from RHESSI, FOXSI, NuSTAR, Solar Orbiter/STIX, EOVSA, and future high-energy missions.

Keywords: solar flares; solar magnetic reconnection; spectral index; solar flare spectra
Statistical Properties of Solar Wind Upstream of Mars: MAVEN Observations

Using the data sets of Mars Atmosphere and Volatile EvolutioN and OMNI for the period 2014 October 10-2020 February 14 and the heliocentric distance of 1-1.66 au, we investigate the statistical properties of solar wind upstream of Mars for the first time. The key parameters, including interplanetary magnetic field (IMF), proton density (N), bulk velocity (∣V∣), and dynamic pressure (Pdyn), are surveyed with regard to variations of solar activity level and heliocentric distance. We find that the parameters ∣IMF∣, N, and Pdyn monotonously decrease with heliocentric distance. Both ∣IMF∣ and Pdyn are generally stronger at a higher solar activity level (F10.7 ≥ 70 sfu), while such activity has little relevance to N. In contrast, ∣V∣ basically keeps a median of about 370 km s-1 and is insensitive to the solar activity level and heliocentric distance. We also find that the IMF upstream of Mars at the higher solar activity level has a much smaller spiral angle in the inward sector; thus, IMF seems "straighter" than that in the outward sector, although that is not so for the inward sector of the upstream of Earth. Our statistical survey can be used as a reference for upstream solar wind of Mars at 1.4 ∼ 1.7 au, and could benefit the studies on solar wind as well as the Martian space environment.

Keywords: solar wind; mars; solar activity; interplanetary magnetic fields; planetary science
Uranus's and Neptune's Stratospheric Water Abundance and Vertical Profile from Herschel-HIFI

Here we present new constraints on Uranus's and Neptune's externally sourced stratospheric water abundance using disk-averaged observations of the 557 GHz emission line from Herschel's Heterodyne Instrument for the Far-Infrared. Derived stratospheric column water abundances are × 1014 cm‑2 for Uranus and ×1014 cm‑2 for Neptune, consistent with previous determinations using ISO-SWS and Herschel-PACS. For Uranus, excellent observational fits are obtained by scaling photochemical model profiles or with step-type profiles with water vapor limited to ≤0.6 mbar. However, Uranus's cold stratospheric temperatures imply a ∼0.03 mbar condensation level, which further limits water vapor to pressures ≤0.03 mbar. Neptune's warmer stratosphere has a deeper ∼1 mbar condensation level, so emission-line pressure broadening can be used to further constrain the water profile. For Neptune, excellent fits are obtained using step-type profiles with cutoffs of ∼0.3–0.6 mbar or by scaling a photochemical model profile. Step-type profiles with cutoffs ≥1.0 mbar or ≤0.1 mbar can be rejected with 4σ significance. Rescaling photochemical model profiles from Moses & Poppe to match our observed column abundances implies similar external water fluxes for both planets: × 104 cm‑2 s‑1 for Uranus and ×104 cm‑2 s‑1 for Neptune. This suggests that Neptune's ∼4 times greater observed water column abundance is primarily caused by its warmer stratosphere preventing loss by condensation, rather than by a significantly more intense external source. To reconcile these water fluxes with other stratospheric oxygen species (CO and CO2) requires either a significant CO component in interplanetary dust particles (Uranus) or contributions from cometary impacts (Uranus, Neptune). * Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Keywords: neptune; uranus; planetary atmospheres; submillimeter astronomy
Magnetic Fields and Star Formation around H II Regions: The S235 Complex

Magnetic fields are ubiquitous and essential in star formation. In particular, their role in regulating formation of stars across diverse environments like H II regions needs to be well understood. In this study, we present magnetic field properties toward the S235 complex using near-infrared (NIR) H-band polarimetric observations, obtained with the Mimir and POLICAN instruments. We selected 375 background stars in the field through combination of Gaia distances and extinctions from NIR colors. The plane-of-sky (POS) magnetic field orientations inferred from starlight polarization angles reveal a curved morphology tracing the spherical shell of the H II region. The large-scale magnetic field traced by Planck is parallel to the Galactic plane. We identified 11 dense clumps using 1.1 mm dust emission, with masses between 33 and 525 M⊙. The clump-averaged POS magnetic field strengths were estimated to be between 36 and 121 μG, with a mean of ∼65 μG. The mass-to-flux ratios for the clumps are found to be subcritical with turbulent Alfvén Mach numbers less than 1, indicating a strongly magnetized region. The clumps show scaling of magnetic field strength versus density with a power-law index of 0.52 ± 0.07, similar to ambipolar diffusion models. Our results indicate that the S235 complex is a region where stellar feedback triggers new stars, and the magnetic fields regulate the rate of new star formation.

Keywords: h ii regions; magnetic fields; interstellar magnetic fields; molecular clouds; starlight polarization; polarimetry