adsabs/SciX_UAT_keywords huggingface dataset:
A Quasar Shedding Its Dust Cocoon at Redshift 2

We present the first near-IR spectroscopy and joint analyses of multiwavelength observations for SDSS J082747.14+425241.1, a dust-reddened, weak broad emission-line quasar (WLQ) undergoing a remarkable broad-absorption line (BAL) transformation. The systemic redshift is more precisely measured to be z = 2.070 ± 0.001 using Hβ compared to z = 2.040 ± 0.003 using Mg II from the literature, signifying an extreme Mg II blueshift of 2140 ± 530 km s-1 relative to Hβ. Using the Hβ-based single-epoch scaling relation with a systematic uncertainty of 0.3 dex, its black hole (BH) mass and Eddington ratio are estimated to be M BH ~ 6.1 × 108 M ⊙ and λ Edd ~ 0.71, indicative of being in a rapidly accreting phase. Our investigations confirm the WLQ nature and the LoBAL → HiBAL transformation, along with a factor of 2 increase in the Mg II+Fe II emission strength and a decrease of 0.1 in E(B - V) over two decades. The kinetic power of this LoBAL wind at R ~ 15 pc from its BH is estimated to be ~43% of the Eddington luminosity, sufficient for quasar feedback upon its host galaxy albeit with an order-of-magnitude uncertainty. This quasar provides a clear example of the long-sought scenario where LoBAL quasars are surrounded by dust cocoons, and wide-angle nuclear winds play a key role in the transition of red quasars evolving into the commonly seen blue quasars.

Keywords: quasars; broad-absorption line quasar; supermassive black holes
A Decade of SCUBA-2: A Comprehensive Guide to Calibrating 450 μm and 850 μm Continuum Data at the JCMT

The Submillimetre Common User Bolometer Array 2 (SCUBA-2) is the James Clerk Maxwell Telescope's continuum imager, operating simultaneously at 450 and 850 μm. SCUBA-2 was commissioned in 2009-2011, and since that time, regular observations of point-like standard sources have been performed whenever the instrument is in use. Expanding the calibrator observation sample by an order of magnitude compared to previous work, in this paper we derive updated opacity relations at each wavelength for a new atmospheric extinction correction, analyze the Flux Conversion Factors used to convert instrumental units to physical flux units as a function of date and observation time, present information on the beam profiles for each wavelength, and update secondary calibrator source fluxes. Between 07:00 and 17:00 UTC, the portion of the night that is most stable to temperature gradients that cause dish deformation, the total flux uncertainty and the peak flux uncertainty measured at 450 μm are found to be 14% and 17%, respectively. Measured at 850 μm, the total flux and peak flux uncertainties are 6% and 7%, respectively. The analysis presented in this work is applicable to all SCUBA-2 projects observed since 2011.

Keywords: submillimeter astronomy; calibration; astronomical methods; observational astronomy; astronomical instrumentation; ground-based astronomy; astronomical techniques
Low-level Carbon Monoxide Line Polarization in Two Protoplanetary Disks: HD 142527 and IM Lup

Magnetic fields are expected to play an important role in accretion processes for circumstellar disks. However, measuring the magnetic field morphology is difficult, especially when given that polarimetric (sub)millimeter continuum observations may not trace the fields in most disks. The Goldreich-Kylafis effect suggests that line polarization is perpendicular or parallel to the magnetic field direction. We attempt to observe CO(2-1), 13CO(2-1), and C18O(2-1) line polarization toward HD 142527 and IM Lup, which are large and bright protoplanetary disks. We use spatial averaging and spectral integration to search for signals in both disks, and we detect a potential CO(2-1) Stokes Q signal toward both disks. The total CO(2-1) polarization fractions are 1.57% ± 0.18% and 1.01% ± 0.10% for HD 142527 and IM Lup, respectively. Our Monte Carlo simulations indicate that these signals are marginal. We also stack Stokes parameters based on the Keplerian rotation, but no signal was found. Across the disk traced by dust of HD 142527, the 3σ upper limits for ${P}_{\mathrm{frac}}$ at 0"5 (∼80 au) resolution are typically less than 3% for CO(2-1) and 13CO(2-1) and 4% for C18O(2-1). For IM Lup the 3σ upper limits for these three lines are typically less than 3%, 4%, and 12%, respectively. Upper limits based on our stacking technique are up to a factor of ∼10 lower, although stacking areas can potentially average out small-scale polarization structure. We also compare our continuum polarization at 1.3 mm to observations at 870 μm from previous studies. The polarization in the northern dust trap of HD 142527 shows a significant change in morphology and an increase in ${P}_{\mathrm{frac}}$ as compared to 870 μm. For IM Lup, the 1.3 mm polarization may be more azimuthal and has a higher ${P}_{\mathrm{frac}}$ than at 870 μm.

Keywords: circumstellar disks; protoplanetary disks; magnetic fields; polarimetry; t tauri stars; herbig ae/be stars; young stellar objects; interferometry
On the Formation of Solar Wind and Switchbacks, and Quiet Sun Heating

The solar coronal heating in quiet Sun (QS) and coronal holes (CHs), including solar wind formation, are intimately tied by magnetic field dynamics. Thus, a detailed comparative study of these regions is needed to understand the underlying physical processes. CHs are known to have subdued intensity and larger blueshifts in the corona. This work investigates the similarities and differences between CHs and QS in the chromosphere using the Mg II h and k, C II line, and transition region using Si IV line, for regions with identical absolute magnetic flux density (∣B∣). We find CHs to have subdued intensity in all of the lines, with the difference increasing with line formation height and ∣B∣. The chromospheric lines show excess upflows and downflows in CH, while Si IV shows excess upflows (downflows) in CHs (QS), where the flows increase with ∣B∣. We further demonstrate that the upflows (downflows) in Si IV are correlated with both upflows and downflows (only downflows) in the chromospheric lines. CHs (QS) show larger Si IV upflows (downflows) for similar flows in the chromosphere, suggesting a common origin to these flows. These observations may be explained due to impulsive heating via interchange (closed-loop) reconnection in CHs (QS), resulting in bidirectional flows at different heights, due to differences in magnetic field topologies. Finally, the kinked field lines from interchange reconnection may be carried away as magnetic field rotations and observed as switchbacks. Thus, our results suggest a unified picture of solar wind emergence, coronal heating, and near-Sun switchback formation.

Keywords: solar wind; quiet solar chromosphere; solar transition region; solar magnetic reconnection; solar magnetic fields; solar chromosphere; solar chromospheric heating; fast solar wind; slow solar wind; quiet sun; solar coronal holes; solar coronal heating
Testing Velocity Kinks as a Planet Detection Method: Do Velocity Kinks in Surface Gas Emission Trace Planetary Spiral Wakes in the Midplane Continuum?

Spiral density waves generated by an embedded planet are understood to cause "kinks" in observed velocity channel maps of CO surface emission by perturbing the gas motion within the spiral arms. If velocity kinks are a reliable probe of embedded planets, we should expect to see the planet-driven spiral arms in other observational tracers. We test this prediction by searching the dust continuum for the midplane counterparts of the spirals responsible for all of the velocity kink planet candidates reported to date whose orbits lie inside the dust continuum disk. We find no clear detection of any spiral structure in current continuum observations for six of the 10 velocity kink planet candidates in our sample (DoAr 25, GW Lup, Sz 129, HD 163296 #2, P94, and HD 143006), despite the high planet masses inferred from the kink amplitude. The remaining four cases include three clear detections of two-armed dust spirals (Elias 27, IM Lup, and WaOph 6) wherein neither spiral arm aligns with a wake originating from a reported planet location, suggesting that under the planetary-origin hypothesis, an accurate method for inferring the location of the planet in the midplane may need to encompass vertical effects. The 10th case, HD 97048, is inconclusive with current knowledge of the disk geometry.

Keywords: planetary-disk interactions; exoplanet detection methods; protoplanetary disks; planet formation; exoplanet formation
Identification of Magnetic Flux Ropes from Parker Solar Probe Observations during the First Encounter

The Parker Solar Probe (PSP) observed an interplanetary coronal mass ejection (ICME) event during its first orbit around the Sun, among many other events. This event is analyzed by applying a wavelet analysis technique to obtain the reduced magnetic helicity, cross helicity, and residual energy, the first two of which are magnetohydrodynamics (MHD) invariants. Our results show that the ICME, as a large-scale magnetic flux rope, possesses high magnetic helicity, very low cross helicity, and highly negative residual energy, thus pointing to a magnetic fluctuation dominated structure. Using the same technique, we also search for small-scale coherent magnetic flux rope structures during the period from 2018 October 22 to November 21, which are intrinsic to quasi-two-dimensional MHD turbulence in the solar wind. Multiple structures with durations between 8 and 300 minutes are identified from PSP in situ spacecraft measurements. The location and scales of these structures are characterized by wavelet spectrograms of the normalized reduced magnetic helicity, normalized cross helicity, and normalized residual energy. Transport theory suggests that these small-scale magnetic flux ropes may contribute to the acceleration of charged particles through magnetic reconnection processes, and the dissipation of these structures may be important for understanding the coronal heating processes.

Keywords: solar magnetic reconnection; solar magnetic fields; interplanetary turbulence
On Fabry-Pérot Etalon-based Instruments. III. Instrument Applications

The spectral, imaging, and polarimetric behavior of Fabry-Pérot etalons have an influence on imaging vector magnetograph instruments based on these devices. The impact depends on the optical configuration (collimated or telecentric), on the relative position of the etalon with respect to the polarimeter, on the type of etalon (air-gapped or crystalline), and even on the polarimetric technique to be used (single-beam or dual-beam). In this paper, we evaluate the artificial line-of-sight velocities and magnetic field strengths that arise in etalon-based instruments, attending to the factors mentioned. We differentiate between signals that are implicit to telecentric mounts due to the wavelength dependence of the point-spread function and those emerging in both collimated and telecentric setups from the polarimetric response of birefringent etalons. For the anisotropic case, we consider two possible locations of the etalon—between the modulator and the analyzer or after it—and we include the effect on different channels when dual-beam polarimetry is employed. We also evaluate the impact of the loss of symmetry produced in telecentric mounts due to imperfections in the illumination and/or to a tilt of the etalon relative to the incident beam.

Keywords: polarimeters; spectrometers; spectropolarimetry; polarimetry; spectroscopy; solar instruments
Wolf-Rayet Galaxies in SDSS-IV MaNGA. I. Catalog Construction and Sample Properties

Wolf-Rayet (WR) galaxies are a rare galaxy type that hosts living high-mass stars during the WR phase (I.e., WR stars) and can thus provide constraints on the stellar initial mass function, massive star formation, stellar evolution models, etc. Spatially resolved spectroscopy should in principle identify WR galaxies more efficiently than single-fiber surveys of galactic centers, as WR stars should be more preferentially found in disks. Using integral field unit data from the ongoing SDSS-IV MaNGA survey, we have performed a thorough search for WR galaxies. We first identify H II regions in each datacube and carry out full spectral fitting to the stacked spectra. We then visually inspect the residual spectrum of each H II region and identify significant WR "blue bumps" at 4600-4750 Å. The WR catalog includes 267 WR regions of ∼500 pc (radius) sizes, distributed in 90 galaxies from MaNGA Product Launch-7. We find that WR regions are exclusively found in galaxies with the bluest colors and highest star formation rates. Most WR galaxies have late-type morphologies and show relatively large asymmetry in their images, implying WR regions exist more in interacting galaxies. We estimate the stellar mass function of WR galaxies and the mass-dependent detection rate (typically ∼2%). This rate is about 40 times higher than that in catalogs from SDSS single-fiber surveys and half that of the CALIFA-based catalog. The difference in detection rates can be explained mainly by three factors: spatial coverage, spectral signal-to-noise ratio, and redshift ranges of parent samples. We tabulate WR galaxy properties for future studies.

Keywords: galaxy evolution; starburst galaxies; star formation; wolf-rayet stars; star forming regions; galaxy mass distribution; redshift surveys; emission line galaxies; galaxies
Surveying Flux Density in Galaxies with Apparent Large Black Holes at Millimeter/Submillimeter Wavelengths

We present millimeter and submillimeter continuum observations for 36 sources with potentially large black hole shadows at 230 and 345 GHz using the Submillimeter Array. The sources are selected based on the criterion of the large diameter of the black hole shadows. Our motivation is to explore the nature of the accretion flow of the potential candidates of low-luminosity active galactic nuclei (LLAGNs) through photometry at millimeter/submillimeter wavelengths. The detected result serves as the pathfinder of future high-angular resolution observations such as the Event Horizon Telescope. As a result, we successfully detected 17 and eight sources at 230 and 345 GHz, respectively. We reveal that three of the detected sources (IC 310, NGC 1277, and NGC 5846) show significant excess at millimeter/submillimeter wavelengths in comparison with the extrapolation both from low-frequency radio and infrared, which are considered to be attributed to the extended jet and dust component, respectively. One possible explanation is that these excesses are associated with the hot accretion flow onto the supermassive black holes of the LLAGNs. By adopting the advection-dominated accretion flow model's semi-analytic model, we obtained the upper bound of the mass accretion rate. Those are less than 10-2 ${\dot{M}}_{\mathrm{EDD}}$ , where ${\dot{M}}_{\mathrm{EDD}}$ is the Eddington mass accretion rate computed via the Eddington luminosity. This is in good agreement with the expected range of the LLAGNs. The ~200 mJy flux densities and negative spectral index of IC 1459 within millimeter and submillimeter wavelengths make it a promising candidate for future submillimeter high-angular resolution experiments for imaging the black hole shadow.

Keywords: low-luminosity active galactic nuclei; submillimeter astronomy; millimeter astronomy; radio astronomy; accretion; black hole physics; redshift surveys; surveys; supermassive black holes
Relating Intermittency and Inverse Cascade to Stochastic Entropy in Solar Wind Turbulence

Turbulent energy transfer in nearly collisionless plasmas can be conceptualized as a scale-to-scale Langevin process. Hence, the statistics of magnetic field fluctuations can be embedded in the framework of stochastic process theory. In this work, we investigate the statistical properties of the pristine solar wind as observed by Parker Solar Probe by defining the cascade trajectories of magnetic field increments and by estimating the stochastic entropy variation along them. Through the stochastic entropy, we can identify two regimes where fluctuations exhibit contrasting statistical properties. In the inertial range, the entropy production is associated with an increase of the flatness indicating the occurrence of intermittency. Otherwise, trajectories associated with an entropy consumption exhibit global scale invariance. In the transition region toward ion scales, the phenomenology switches: entropy-consuming trajectories exhibit a sudden flatness increase, associated with the presence of small-scale intermittency, while entropy-producing trajectories display a nearly constant flatness. Results are interpreted in terms of physical processes consistent with an accumulation of energy at ion scales.

Keywords: solar wind; space plasmas; interplanetary turbulence; interplanetary physics
Galaxy Quenching at the High Redshift Frontier: A Fundamental Test of Cosmological Models in the Early Universe with JWST-CEERS

We present an analysis of the quenching of star formation in massive galaxies (M * > 109.5 M ⊙) within the first 0.5–3 Gyr of the Universe's history utilizing JWST-CEERS data. We utilize a combination of advanced statistical methods to accurately constrain the intrinsic dependence of quenching in a multidimensional and intercorrelated parameter space. Specifically, we apply random forest classification, area statistics, and a partial correlation analysis to the JWST-CEERS data. First, we identify the key testable predictions from two state-of-the-art cosmological simulations (IllustrisTNG and EAGLE). Both simulations predict that quenching should be regulated by supermassive black hole mass in the early Universe. Furthermore, both simulations identify the stellar potential (ϕ *) as the optimal proxy for black hole mass in photometric data. In photometric observations, where we have no direct constraints on black hole masses, we find that the stellar potential is the most predictive parameter of massive galaxy quenching at all epochs from z = 0–8, exactly as predicted by simulations for this sample. The stellar potential outperforms stellar mass, galaxy size, galaxy density, and Sérsic index as a predictor of quiescence at all epochs probed in JWST-CEERS. Collectively, these results strongly imply a stable quenching mechanism operating throughout cosmic history, which is closely connected to the central gravitational potential in galaxies. This connection is explained in cosmological models via massive black holes forming and growing in deep potential wells, and subsequently quenching galaxies through a mix of ejective and preventative active galactic nucleus feedback.

Keywords: galaxy evolution; galaxy formation
Strength of the Termination Shock Inferred from the Globally Distributed Energetic Neutral Atom Flux from IBEX

In this study, we estimate the heliospheric termination shock (HTS) compression ratio at multiple directions in the sky from a quantitative comparison of the observed and simulated inner heliosheath (IHS) energetic neutral atom (ENA) fluxes. We use a 3D steady-state simulation of the heliosphere to simulate the ENA fluxes by postprocessing the MHD plasma using a multi-Maxwellian distribution for protons in the IHS. The simulated ENA fluxes are compared with time exposure-averaged IBEX-Hi data for the first 3 yr of the mission. The quantitative comparison is performed by calculating the fractional difference in the spectral slope between the observed and simulated ENA fluxes for a range of compression ratios, where the simulated ENA spectrum is varied as a function of downstream pickup ion temperature as a function of compression ratio. The estimated compression ratio in a particular direction is determined by the minimum value of the fractional difference in spectral slope. Our study shows that the compression ratio estimated by this method is in close agreement with the large-scale compression ratio observed by Voyager 2 in its travel direction. Also, the compression ratio in other directions near the ecliptic plane is similar to the compression ratio at the Voyager 2 direction. The weakest shock compression is found to be on the port side of the heliosphere at direction (27°, 15°). This is the first study to estimate the HTS compression ratio at multiple directions in the sky from IBEX data.

Keywords: termination shock; heliosphere; pickup ions; heliosheath; solar wind; charge exchange ionization
X-Ray Emission from the Jets and Lobes of the Spiderweb

Deep Chandra and Very Large Array imaging reveals a clear correlation between X-ray and radio emission on scales ~100 kpc in the Spiderweb radio galaxy at z = 2.16. The X-ray emission associated with the extended radio source is likely dominated by inverse Compton upscattering of cosmic microwave background photons by the radio-emitting relativistic electrons. For regions dominated by high surface brightness emission, such as hot spots and jet knots, the implied magnetic fields are ~50-70 μG. The nonthermal pressure in these brighter regions is then ~9 × 10-10 dynes cm-2, or three times larger than the nonthermal pressure derived assuming minimum energy conditions, and an order of magnitude larger than the thermal pressure in the ambient cluster medium. Assuming ram pressure confinement implies an average advance speed for the radio source of ~2400 km s-1 and a source age of ~3 × 107 yr. Considering the lower surface brightness, diffuse radio-emitting regions, we identify an evacuated cavity in the Lyα emission coincident with the tail of the eastern radio lobe. Making reasonable assumptions for the radio spectrum, we find that the relativistic electrons and fields in the lobe are plausibly in pressure equilibrium with the thermal gas and close to a minimum energy configuration. The radio morphology suggests that the Spiderweb is a high-z example of the rare class of hybrid morphology radio sources (or HyMoRS), which we attribute to interaction with the asymmetric gaseous environment indicated by the Lyα emission.

Keywords: radio galaxies; high-energy cosmic radiation; radio jets; cosmic microwave background radiation
Adsorption Kinetics of Water and Argon on Lunar Grains

Adsorption residence times of water on lunar grains play an essential role for the migration and sequestration of water on the Moon, but estimates vary by over 10 orders of magnitude for the same temperature. Here, the physical chemistry literature for the interaction of water vapor and argon with silicates is reviewed, and available measurements of adsorption on lunar samples are used to quantify adsorption times. The wide range of adsorption energies, measured or postulated, is explained by activated surface sites with high desorption energies. Passivation, the opposite of activation, occurs quickly in laboratory settings and is expected on longer timescales at shallow depths on the Moon. A quantitative parameterization of desorption rates, intended for a wide range of adsorbate concentrations and temperatures, is constructed and used in model calculations. Grain surface diffusion plays a key role for desorption rates and also reduces photodestruction rates. For ice buried beneath lunar soil, multilayer adsorption is expected well before the depth of the ice is reached.

Keywords: lunar surface; lunar science; lunar regolith; water vapor; astrochemistry; the moon; ice physics