adsabs/SciX_UAT_keywords huggingface dataset:
Revealing a Centrally Condensed Structure in OMC-3/MMS 3 with ALMA High-resolution Observations

Using the Atacama Large Millimeter/submillimeter Array (ALMA), we investigated the peculiar millimeter source MMS 3 located in the Orion Molecular Cloud 3 (OMC-3) region in the 1.3 mm continuum, CO (J = 2-1), SiO (J = 5-4), C18O (J = 2-1), N2D+ (J = 3-2), and DCN (J = 3-2) emissions. With the ALMA high angular resolution (∼0"2), we detected a very compact and highly centrally condensed continuum emission with a size of 0"45 × 0"32 (P.A. = 0°22). The peak position coincides with the locations of previously reported Spitzer/IRAC and X-ray sources within their positional uncertainties. We also detected an envelope with a diameter of ∼6800 au (P.A. = 75°) in the C18O (J = 2-1) emission. Moreover, a bipolar outflow was detected in the CO (J = 2-1) emission for the first time. The outflow is elongated roughly perpendicular to the long axis of the envelope detected in the C18O (J = 2-1) emission. Compact high-velocity CO gas in the (redshifted) velocity range of 22-30 km s-1, presumably tracing a jet, was detected near the 1.3 mm continuum peak. A compact and faint redshifted SiO emission was marginally detected in the CO outflow lobe. The physical quantities of the outflow in MMS 3 are somewhat smaller than those in other sources in the OMC-3 region. The centrally condensed object associated with the near-infrared and X-ray sources, the flattened envelope, and the faint outflow indicate that MMS 3 harbors a low-mass protostar with an age of ∼103 yr.

Keywords: star formation; protostars
Mid-infrared Spectrum of the Disk around the Forming Companion GQ Lup B Revealed by JWST/MIRI

GQ Lup B is a forming brown dwarf companion (M ∼ 10–30 M J) showing evidence for an infrared excess associated with a disk surrounding the companion itself. Here we present mid-infrared (MIR) observations of GQ Lup B with the Medium Resolution Spectrometer (MRS) on JWST, spanning 4.8–11.7 μm. We remove the stellar contamination using reference differential imaging based on principal component analysis, demonstrating that the MRS can perform high-contrast science. Our observations provide a sensitive probe of the disk surrounding GQ Lup B. We find no sign of a silicate feature, similar to other disks surrounding very low-mass objects, which likely implies significant grain growth ( ${a}_{\min }\gtrsim 5$ μm) and potentially dust settling. Additionally, we find that if the emission is dominated by an inner wall, the disk around the companion might have an inner cavity larger than the one set by sublimation. Conversely, if our data probe the emission from a thin flat disk, we find the disk to be very compact. More observations are required to confirm this findings and assess the vertical structure of the disk. This approach paves the path to the future study of circumplanetary disks and their physical properties. Our results demonstrate that MIR spectroscopic observations can reveal the physical characteristics of disks around forming companions, providing unique insights into the formation of giant planets, brown dwarfs, and their satellites.

Keywords: planet formation; high contrast spectroscopy
Stellar Properties for a Comprehensive Collection of Star-forming Regions in the SDSS APOGEE-2 Survey

The Sloan Digital Sky Survey IV APOGEE-2 primary science goal was to observe red giant stars throughout the Galaxy to study its dynamics, morphology, and chemical evolution. The APOGEE instrument, a high-resolution 300-fiber H-band (1.55-1.71 μm) spectrograph, is also ideal to study other stellar populations in the Galaxy, among which are a number of star-forming regions and young open clusters. We present the results of the determination of six stellar properties (T eff, $\mathrm{log}\,g$ , [Fe/H], L/L ⊙, M/M ⊙, and age) for a sample that is composed of 3360 young stars, of subsolar to supersolar types, in 16 Galactic star formation and young open cluster regions. Those sources were selected by using a clustering method that removes most of the field contamination. Samples were also refined by removing targets affected by various systematic effects of the parameter determination. The final samples are presented in a comprehensive catalog that includes all six estimated parameters. This overview study also includes parameter spatial distribution maps for all regions and Hertzsprung-Russell ( $\mathrm{log}L/{L}_{\odot }$ vs. T eff) diagrams. This study serves as a guide for detailed studies on individual regions and paves the way for the future studies on the global properties of stars in the pre-main-sequence phase of stellar evolution using more robust samples. * Based on SDSS Data Releases 16 and 17.

Keywords: young star clusters; pre-main sequence stars; star forming regions; fundamental parameters of stars; near infrared astronomy
Geoeffectiveness of Interplanetary Alfvén Waves. II. Spectral Characteristics and Geomagnetic Responses

Using multipoint observations over 10 yr near 1 au, we investigate the spectra (5 minutes to 2 hr) of interplanetary Alfvén waves and the responses in the geomagnetic activities. We compute the two-point correlations of the wave magnetic field between the ACE and the THEMIS spacecraft, which are separated by ~200 Earth radius (R E) in the solar wind. Alfvén waves associated with high two-point correlations exhibit steep spectra (spectra index ~-1.63). Such Alfvén waves occur mostly in slow-speed streams. By contrast, Alfvén waves with low two-point correlations exhibit flatter spectra (spectra index ~-1.51) with a relative enhancement of power above 2 × 10-4 Hz. The occurrence of Alfvén waves with low two-point correlations is more equally distributed between high-speed and low-speed streams. In general, interplanetary Alfvén waves show correlations with moderate geomagnetic responses in symmetric ring-current intensity, SuperMAG electrojet (SME), and Kp indices. Statistical analyses indicate that the Alfvén waves with flat spectra correspond to stronger responses in the geomagnetic indices than those with steep spectra, suggesting the importance of the tens of minutes (30-90 minutes) Alfvénic power spectra in the generation of SME/Auroral Electrojets. These observations may shed light on the response of the magnetosphere to fluctuating interplanetary magnetic field B z .

Keywords: planetary magnetospheres; solar-terrestrial interactions; solar-planetary interactions
RR Lyrae Mid-infrared Period-Luminosity-Metallicity and Period-Wesenheit-Metallicity Relations Based on Gaia DR3 Parallaxes

We present new empirical infrared period-luminosity-metallicity (PLZ) and period-Wesenheit-metallicity (PWZ) relations for RR Lyae based on the latest Gaia Early Data Release 3 (EDR3) parallaxes. The relations are provided in the Wide-field Infrared Survey Explorer (WISE) W1 and W2 bands, as well as in the W(W1, V - W1) and W(W2, V - W2) Wesenheit magnitudes. The relations are calibrated using a very large sample of Galactic halo field RR Lyrae stars with homogeneous spectroscopic [Fe/H] abundances (over 1000 stars in the W1 band), covering a broad range of metallicities (-2.5 ≲ [Fe/H] ≲ 0.0). We test the performance of our PLZ and PWZ relations by determining the distance moduli of both galactic and extragalactic stellar associations: the Sculptor dwarf spheroidal galaxy in the Local Group (finding ${\bar{\mu }}_{0}=19.47\pm 0.06$ ), the Galactic globular clusters M4 ( ${\bar{\mu }}_{0}=11.16\pm 0.05$ ), and the Reticulum globular cluster in the Large Magellanic Cloud ( ${\bar{\mu }}_{0}=18.23\pm 0.06$ ). The distance moduli determined through all our relations are internally self-consistent (within ≲0.05 mag) but are systematically smaller (by ~2-3σ) than previous literature measurements taken from a variety of methods/anchors. However, a comparison with similar recent RR Lyrae empirical relations anchored with EDR3 likewise shows, to varying extents, a systematically smaller distance modulus for PLZ/PWZ RR Lyrae relations.

Keywords: rr lyrae variable stars; standard candles; stellar distance
SILVERRUSH. XII. Intensity Mapping for Lyα Emission Extending over 100-1000 Comoving Kpc around z 2-7 LAEs with Subaru HSC-SSP and CHORUS Data

We conduct intensity mapping to probe for extended diffuse Lyα emission around Lyα emitters (LAEs) at z ~2-7, exploiting very deep (~26 mag at 5σ) and large-area (~4.5 deg2) Subaru/Hyper Suprime-Cam narrowband (NB) images and large LAE catalogs consisting of a total of 1540 LAEs at z = 2.2, 3.3, 5.7, and 6.6 obtained by the HSC-SSP and CHORUS projects. We calculate the spatial correlations of these LAEs with ~1-2 billion pixel flux values of the NB images, deriving the average Lyα surface brightness (SBLyα ) radial profiles around the LAEs. By carefully estimating systematics such as fluctuations of sky background and point-spread functions, we detect Lyα emission at 100-1000 comoving kpc around z = 3.3 and 5.7 LAEs at the 3.2σ and 3.7σ levels, respectively, and tentatively (=2.0σ) at z = 6.6. The emission is as diffuse as ~10-20-10-19 erg s-1 cm-2 arcsec-2 and extended beyond the virial radius of a dark matter halo with a mass of 1011 M ⊙. While the observed SBLyα profiles have similar amplitudes at z = 2.2-6.6 within the uncertainties, the intrinsic SBLyα profiles (corrected for the cosmological dimming effect) increase toward high redshifts. This trend may be explained by increasing hydrogen gas density due to the evolution of the cosmic volume. Comparisons with theoretical models suggest that extended Lyα emission around an LAE is powered by resonantly scattered Lyα photons in the CGM and IGM that originate from the inner part of the LAE and/or neighboring galaxies around the LAE.

Keywords: galaxy formation; galaxy evolution; high-redshift galaxies; circumgalactic medium; intergalactic medium
SCExAO/CHARIS Multiwavelength High-contrast Imaging of the BD+45°598 Debris Disk

We present a multiwavelength (1.16–2.37 μm) view of the debris disk around BD+45°598, using the Subaru Coronagraphic Extreme Adaptive Optics system paired with the Coronagraphic High Angular Resolution Imaging Spectrograph. With an assumed age of 23 Myr, this source allows us to study the early evolution of debris disks and search for forming planets. We fit a scattered light model to our disk using a differential evolution algorithm, and constrain its geometry. We find the disk to have a peak density radius of R 0 = 109.6 au, an inclination of i = 88.1°, and position angle PA = 111.0°. While we do not detect a substellar companion in the disk, our calculated contrast limits indicate sensitivity to planets as small as ∼10M Jup at a projected separation of 12 au of the star, and as small as ∼4M Jup beyond 38 au. When measuring intensity as a function of wavelength, the disk color constrains the minimum dust grain size within a range of ∼0.13–1.01 μm.

Keywords: debris disks; circumstellar disks; near infrared astronomy; adaptive optics; direct imaging
Gaia Gaps and the Physics of Low-mass Stars. I. The Fully Convective Boundary

The Gaia M-dwarf gap is a significant underdensity of stars observed near MG = 10.2 in a color-magnitude diagram for stars within 200 pc of the Sun. It has been proposed that the gap is the manifestation of structural instabilities within stellar interiors due to nonequilibrium 3He fusion prior to some stars becoming fully convective. To test this hypothesis, we use Dartmouth stellar evolution models, MARCS model atmospheres, and simple stellar population synthesis to create synthetic MG-(GBP - GRP) color-magnitude diagrams. We confirm that the proposed 3He instability is responsible for the appearance of the M-dwarf gap. Our synthetic gap shows qualitatively similar features to the observed gap, including its vertical extent in MG, its slope in the color-magnitude diagram, and its relative prominence at bluer colors as compared to redder colors. Furthermore, corresponding overdensities of stars above the gap are reproduced by the models. While qualitatively similar, the synthetic gap is approximately 0.2 magnitudes bluer, and when this color offset is accounted for, it is 0.16 magnitudes brighter than the observed gap. Our results reveal that the Gaia M-dwarf gap is sensitive to conditions within cores of M-dwarf stars, making the gap a powerful tool for testing the physics of M-dwarf stars and potentially using M dwarfs to understand the local star formation history.

Keywords: stellar evolution; stellar evolutionary models; hertzsprung russell diagram; main sequence; stellar interiors; m dwarf stars
How Have Astronomers Cited Other Fields in the Last Decade?

We present a citation pattern analysis between astronomical papers and 13 other disciplines, based on the arXiv database over the past decade (2010-2020). We analyze 12,600 astronomical papers citing over 14,531 unique publications outside astronomy. Two striking patterns are unraveled. First, general relativity recently became the most cited field by astronomers, a trend highly correlated with the discovery of gravitational waves. Second, the fast growth of referenced papers in computer science and statistics, the first with a notable 15 fold increase since 2015. Such findings confirm the critical role of interdisciplinary efforts involving astronomy, statistics, and computer science in recent astronomical research.

Keywords: interdisciplinary astronomy; astroinformatics; astrostatistics
Kinetic Simulations of Cosmic-Ray-modified Shocks. II. Particle Spectra

Diffusive shock acceleration is a prominent mechanism for producing energetic particles in space and in astrophysical systems. Such energetic particles have long been predicted to affect the hydrodynamic structure of the shock, in turn leading to CR spectra flatter than the test-particle prediction. However, in this work along with a companion paper, we use self-consistent hybrid (kinetic ion-fluid electron) simulations to show for the first time how CR-modified shocks actually produce steeper spectra. The steepening is driven by the enhanced advection of CRs embedded in magnetic turbulence downstream of the shock, in what we call the "postcursor." These results are consistent with multiwavelength observations of supernovae and supernova remnants and have significant phenomenological implications for space/astrophysical shocks in general.

Keywords: plasma astrophysics; plasma physics; shocks; cosmic rays; galactic cosmic rays; supernovae; supernova remnants
Planet Formation by Gas-assisted Accretion of Small Solids

We compute the accretion efficiency of small solids, with radii 1 cm ≤ R s ≤ 10 m, on planets embedded in gaseous disks. Planets have masses 3 ≤ M p ≤ 20 Earth masses (M ⊕) and orbit within 10 au of a solar mass star. Disk thermodynamics is modeled via 3D radiation-hydrodynamics calculations that typically resolve the planetary envelopes. Both icy and rocky solids are considered, explicitly modeling their thermodynamic evolution. The maximum efficiencies of 1 ≤ R s ≤ 100 cm particles are generally ≲10%, whereas 10 m solids tend to accrete efficiently or be segregated beyond the planet's orbit. A simplified approach is applied to compute the accretion efficiency of small cores, with masses M p ≤ 1 M ⊕ and without envelopes, for which efficiencies are approximately proportional to . The mass flux of solids, estimated from unperturbed drag-induced drift velocities, provides typical accretion rates dM p /dt ≲ 10‑5 M ⊕ yr‑1. In representative disk models with an initial gas-to-dust mass ratio of 70–100 and total mass of 0.05–0.06 M ⊙, the solids' accretion falls below 10‑6 M ⊕ yr‑1 after 1–1.5 Myr. The derived accretion rates, as functions of time and planet mass, are applied to formation calculations that compute dust opacity self-consistently with the delivery of solids to the envelope. Assuming dust-to-solid coagulation times of ≈0.3 Myr and disk lifetimes of ≈3.5 Myr, heavy-element inventories in the range 3–7 M ⊕ require that ≈90–150 M ⊕ of solids cross the planet's orbit. The formation calculations encompass a variety of outcomes, from planets a few times M ⊕, predominantly composed of heavy elements, to giant planets. The peak luminosities during the epoch of the solids' accretion range from ≈10‑7 to ≈10‑6 L ⊙.

Keywords: stellar accretion disks; radiative magnetohydrodynamics; astrophysical fluid dynamics; computational methods; planet formation; planetary-disk interactions; planetesimals; protoplanetary disks; extrasolar rocky planets; extrasolar gaseous planets; extrasolar gaseous giant planets; planetary atmospheres
Inferring Pulsar Periods from Synchro-curvature Spectra

The period and the period derivative of a pulsar are critical magnitudes for defining the properties of the magnetospheric size and plasma dynamics. The pulsar light cylinder, the magnetic field intensity nearby it, and the curvature radius all depend on these timing properties, and shape the observed high-energy synchro-curvature emission. Therefore, the radiative properties of pulsars are inextricably linked to them. This fact poses the question of how well does a given pulsar's spectral energy distribution embed information of the timing parameters, and if so, whether we can deduce them if they have not been measured directly. This is relevant to possibly constrain the timing properties of potential pulsar candidates among unidentified γ-ray sources. We consider well-measured pulsar spectra blinding us from the knowledge of their timing properties, and address this question by using our radiative synchro-curvature model that was proven able to fit the observed spectra of the pulsar population. We find that in the majority of the cases studied (8 out of 13), the spin period is constrained within a range of about 1 order of magnitude, within which the real period lies. In the other cases, there is degeneracy and no period range can be constrained. This can be used to facilitate the blind search of pulsed signals.

Keywords: gamma-ray sources; x-ray sources; pulsars; non-thermal radiation sources
Shedding Light on the Ejection History of Molecular Outflows: Multiple Velocity Modes and Precession

Variable accretion has been well studied in the evolved stages of low-mass star formation. However, the accretion history in the initial phases of star formation is still a seldom studied topic. The outflows and jets emerging from protostellar objects could shed some light on their accretion history. We consider the recently studied case of W43-MM1, a protocluster containing 46 outflows driven by 27 protostellar cores. The outflow kinematics of the individual cores and associated knots in W43-MM1 indicate episodic protostellar ejection. We take the observed parameters of an individual core system (core #8) and perform 3D hydrodynamic simulations of such a system, including episodic changes in the velocity of the outflow. The simulations consist of a collimated jet emerging from a core, taking into account one- and two-velocity modes in the variation of the ejection velocity of the jet. In addition, we investigated the effect of including the precession of the jet in the one- and two-velocity-mode models. From the simulations, we constructed position–velocity diagrams and compared them with the observations. We find that including a second mode in the ejection velocity, as well as the precession, are required to explain the positions of the outflow knots and other position–velocity features observed in core #8 in W43-MM1.

Keywords: stellar jets; massive stars; hydrodynamical simulations
A Chromatic Treatment of Linear Polarization in the Solar Corona at the 2023 Total Solar Eclipse

The broadband solar K-corona is linearly polarized due to Thomson scattering. Various strategies have been used to represent coronal polarization. Here, we present a new way to visualize the polarized corona, using observations from the 2023 April 20 total solar eclipse in Australia in support of the Citizen CATE 2024 project. We convert observations in the common four-polarizer orthogonal basis (0°, 45°, 90°, & 135°) to -60°, 0°, and +60° (MZP) polarization, which is homologous to R, G, B color channels. The unique image generated provides some sense of how humans might visualize polarization if we could perceive it in the same way we perceive color.

Keywords: solar k corona; solar eclipses; solar corona; polarimetry
A Deep Search for Emission from "Rock Comet" (3200) Phaethon at 1 au

We present a deep imaging and spectroscopic search for emission from (3200) Phaethon, a large near-Earth asteroid that appears to be the parent of the strong Geminid meteoroid stream, using the 4.3 m Lowell Discovery Telescope. Observations were conducted on 2017 December 14-18 when Phaethon passed only 0.07 au from the Earth. We determine the 3σ upper level of dust and CN production rates to be 0.007-0.2 kg s-1 and 2.3 × 1022 molecules s-1 through narrowband imaging. A search in broadband images taken through the SDSS r' filter shows no 100 m class fragments in Phaethon's vicinity. A deeper but star-contaminated search also shows no sign of fragments down to 15 m. Optical spectroscopy of Phaethon and comet C/2017 O1 (ASASSN) as a comparison confirms the absence of cometary emission lines from Phaethon and yields 3σ upper levels of CN, C2, and C3 of ∼1024-1025 molecules s-1, 2 orders of magnitude higher than the CN constraint placed by narrowband imaging, due to the much narrower on-sky aperture of the spectrographic slit. We show that narrowband imaging could provide an efficient way to look for weak gas emission from near-extinct bodies near the Earth, though these observations require careful interpretation. Assuming Phaethon's behavior is unchanged, our analysis shows that the DESTINY+ mission, currently planning to explore Phaethon in 2026, may not be able to directly detect a gas coma.

Keywords: comets; long period comets; asteroids; near-earth objects; apollo group; flyby missions; coma dust
EXOREL ${}^{{\mathfrak{R}}} : A Bayesian Inverse Retrieval Framework for Exoplanetary Reflected Light Spectra

The high-contrast imaging technique is meant to provide insight into those planets orbiting several astronomical units from their host star. Space missions such as Wide-Field InfraRed Survey Telescope, Habitable Exoplanet Imaging Mission, and Large Ultra-Violet/Optical/InfraRed Surveyor will measure reflected light spectra of cold gaseous and rocky planets. To interpret these observations, we introduce EXOREL ${}^{{\mathfrak{R}}} (Exoplanetary Reflected Light Retrieval), a novel Bayesian retrieval framework to retrieve cloud properties and atmospheric structures from exoplanetary reflected light spectra. As a unique feature, it assumes a vertically nonuniform volume mixing ratio (VMR) profile of water and ammonia, and uses it to construct cloud densities. In this way, clouds and molecular mixture ratios are consistent. We apply EXOREL ${}^{{\mathfrak{R}}} on three test cases: two exoplanets (υ And e and 47 Uma b) and Jupiter. We show that we are able to retrieve the concentration of methane in the atmosphere, and estimate the position of clouds when the signal-to-noise ratio of the spectrum is higher than 15, in line with previous works. Moreover, we described the ability of our model to give a chemical identity to clouds, and we discussed whether or not we can observe this difference in the planetary reflection spectrum. Finally, we demonstrate how it could be possible to retrieve molecular concentrations (water and ammonia in this work) below the clouds by linking the nonuniform VMR profile to the cloud presence. This will help to constrain the concentration of water and ammonia unseen in direct measurements.

Keywords: planetary science; planetary atmospheres; bayesian statistics; exoplanets; extrasolar gaseous giant planets; radiative transfer; spectroscopy