adsabs/SciX_UAT_keywords huggingface dataset:
Prediction for Arrival Time and Parameters of Corotation Interaction Regions using Earth–Mars Correlated Events from Tianwen-1, MAVEN, and Wind Observations

Using the Stream Interaction Regions list from the Tianwen-1/Mars Orbiter Magnetometer (MOMAG) data between 2021 November and 2021 December and from Wind observations, we present an accurate prediction for the arrival time and in situ parameters of corotating interaction regions (CIRs) when the Earth and Mars have large longitudinal separations. Since CIRs were detected earlier at Earth than at Mars during the period examined, we employ Earth-based CIR detections for predicting CIR observations at Mars. The arrival time is calculated by the Parker spiral model under the assumption of steady corotation of the Sun and coronal holes, while the in situ parameters are derived from Wind data through radial dependent scaling laws. The CIR prediction results are compared to the actual observations obtained from the MOMAG and Mars Ion and Neutral Particle Analyzer instruments onboard Tianwen-1, as well as the Magnetometer and Solar Wind Ion Analyzer instruments onboard MAVEN. The predicted arrival time is close to the observed values with relative errors less than 10%, and the expected in situ data show a good consistency with the Martian measurements. The comparison results indicate that the prediction method has good performance and will be helpful for comparative analysis with Tianwen-1 observations at Mars in the future.

Keywords: space weather; heliosphere
Complex Network View of the Sun's Magnetic Patches. I. Identification

Solar and stellar magnetic patches (i.e., magnetic fluxes that reach the surface from the interior) are believed to be the primary sources of a star's atmospheric conditions. Here, we apply the complex network approach and investigate its efficacy in the identification of these features. For this purpose, we use the line-of-sight magnetograms provided by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. We construct the magnetic network following a specific visibility graph condition between pairs of pixels with opposite polarities and search for possible links between these regions. The complex network facilitates the construction of node degrees and PageRank images, and applying the downhill algorithm to node-degree images allows for the grouping of pixels into features corresponding to one-to-one matches with magnetogram patches. This approach promisingly serves to identify the nontrivial morphological structure of the magnetic patches for small and large sizes. We observe that the changes in the features of the node-degree images effectively correspond to the cospatial magnetic patches over time. Through visual assessment, we estimate an average false-negative error rate of approximately 1% in identifying small-scale features (one or two pixels in size).

Keywords: the sun; solar active regions
The Mass Density of Merging Binary Black Holes over Cosmic Time

The connection between the binary black hole (BBH) mergers observed by LIGO-Virgo-KAGRA and their stellar progenitors remains uncertain. Specifically, the fraction ϵ of stellar mass that ends up in BBH mergers and the delay time τ between star formation and merger carry information about the astrophysical processes that produce merging BBHs. We model the merger rate in terms of cosmic star formation, coupled with a metallicity-dependent efficiency ϵ and a distribution of delay times τ, and infer these parameters with data from the Third Gravitational-Wave Transient Catalog. The progenitors to merging BBHs preferentially form in low-metallicity environments with a low-metallicity efficiency of and a high-metallicity efficiency of at 90% credibility. The data also prefer short delay times. For a power-law distribution p(τ) ∝ τ α , we find and α < ‑1.32 at 90% credibility. Our model allows us to extrapolate the mass density in BBHs to high redshifts. We cumulatively integrate our density rate over time to get the total density of merging stellar-mass BBHs as a function of redshift. Today, BBH mergers are only ∼0.01% of the total stellar-mass density created by >10 M ⊙ progenitors. However, because massive stars are short lived, there may be more mass in merging BBHs than in living massive stars as early as ∼2.5 Gyr ago. We also compare to the mass in supermassive black holes, finding that the densities were comparable ∼12.5 Gyr ago, but their densities quickly increased to ∼75 times the density in merging stellar-mass BBHs by z ∼ 1.

Keywords: gravitational waves; gravitational wave astronomy; black holes; binary stars; compact objects; stellar remnants; gravitational wave sources; massive stars; astrophysical black holes; stellar mass black holes; metallicity
Vortex Fiber Nulling for Exoplanet Observations: First Direct Detection of M Dwarf Companions around HIP 21543, HIP 94666, and HIP 50319

Vortex fiber nulling (VFN) is a technique for detecting and characterizing faint companions at small separations from their host star. A near-infrared (∼2.3 μm) VFN demonstrator mode was deployed on the Keck Planet Imager and Characterizer (KPIC) instrument at the Keck Observatory and presented earlier. In this Letter, we present the first VFN companion detections. Three targets, HIP 21543 Ab, HIP 94666 Ab, and HIP 50319 B, were detected with host–companion flux ratios between 70 and 430 at and within one diffraction beamwidth (λ/D). We complement the spectra from KPIC VFN with flux ratio and position measurements from the CHARA Array to validate the VFN results and provide a more complete characterization of the targets. This Letter reports the first direct detection of these three M dwarf companions, yielding their first spectra and flux ratios. Our observations provide measurements of bulk properties such as effective temperatures, radial velocities, and $v\sin i$ , and verify the accuracy of the published orbits. These detections corroborate earlier predictions of the KPIC VFN performance, demonstrating that the instrument mode is ready for science observations.

Keywords: exoplanet detection methods; astronomical instrumentation; direct detection interferometry; high resolution spectroscopy; companion stars
3D Radiative Transfer for Exoplanet Atmospheres. gCMCRT: A GPU-accelerated MCRT Code

Radiative transfer (RT) is a key component for investigating atmospheres of planetary bodies. With the 3D nature of exoplanet atmospheres being important in giving rise to their observable properties, accurate and fast 3D methods are required to be developed to meet future multidimensional and temporal data sets. We develop an open-source GPU RT code, gCMCRT, a Monte Carlo RT forward model for general use in planetary atmosphere RT problems. We aim to automate the post-processing pipeline, starting from direct global circulation model (GCM) output to synthetic spectra. We develop albedo, emission, and transmission spectra modes for 3D and 1D input structures. We include capability to use correlated-k and high-resolution opacity tables, the latter of which can be Doppler-shifted inside the model. We post-process results from several GCM groups, including ExoRad, SPARC/MITgcm THOR, UK Met Office UM, Exo-FMS, and the Rauscher model. Users can therefore take advantage of desktop and HPC GPU computing solutions. gCMCRT is well suited for post-processing large GCM model grids produced by members of the community and for high-resolution 3D investigations.

Keywords: exoplanet atmospheres; radiative transfer; hot jupiters; high resolution spectroscopy
The X-shooter/ALMA Sample of Quasars in the Epoch of Reionization. II. Black Hole Masses, Eddington Ratios, and the Formation of the First Quasars

We present measurements of black hole masses and Eddington ratios (λ Edd) for a sample of 38 bright (M 1450 < -24.4 mag) quasars at 5.8 ≲ z ≲ 7.5, derived from Very Large Telescope/X-shooter near-IR spectroscopy of their broad C IV and Mg II emission lines. The black hole masses (on average, M BH ~ 4.6 × 109 M ⊙) and accretion rates (0.1 ≲ λ Edd ≲ 1.0) are broadly consistent with that of similarly luminous 0.3 ≲ z ≲ 2.3 quasars, but there is evidence for a mild increase in the Eddington ratio above z ≳ 6. Combined with deep Atacama Large Millimeter/submillimeter Array (ALMA) observations of the [C II] 158 μm line from the host galaxies and VLT/MUSE investigations of the extended Lyα halos, this study provides fundamental clues to models of the formation and growth of the first massive galaxies and black holes. Compared to local scaling relations, z ≳ 5.7 black holes appear to be over-massive relative to their hosts, with accretion properties that do not change with host galaxy morphologies. Assuming that the kinematics of the T ~ 104 K gas, traced by the extended Lyα halos, are dominated by the gravitational potential of the dark matter halo, we observe a similar relation between black hole mass and circular velocity as reported for z ~ 0 galaxies. These results paint a picture where the first supermassive black holes reside in massive halos at z ≳ 6 and lead the first stages of galaxy formation by rapidly growing in mass with a duty cycle of order unity. The duty cycle needs to drastically drop toward lower redshifts, while the host galaxies continue forming stars at a rate of hundreds of solar masses per year, sustained by the large reservoirs of cool gas surrounding them.

Keywords: quasars; reionization; supermassive black holes
Wide-field Survey of Dwarf Satellite Systems around 10 Hosts in the Local Volume

We present the results of an extensive search for dwarf satellite galaxies around 10 primary host galaxies in the Local Volume (LV, D < 12 Mpc) using archival CFHT/MegaCam imaging data. The hosts span a wide range in properties, with stellar masses ranging from that of the Large Magellanic Cloud to ∼3 times that of the Milky Way. The surveyed hosts are: NGC 1023, NGC 1156, NGC 2903, NGC 4258, NGC 4565, NGC 4631, NGC 5023, M51, M64, and M104. We detect satellite candidates using a consistent semi-automated detection algorithm that is optimized for the detection of low surface brightness objects. Depending on the host, our completeness limit is Mg ∼ -8 to -10 (assuming the distance of the host). We detect objects with surface brightness down to μ0,g∼ 26 mag arcsec-2 at ≳90% completeness. The survey areas of the six best-surveyed hosts cover most of the inner projected R< 150 kpc area, which will roughly double the number of massive LV hosts surveyed at this level of area and luminosity completeness, once distances are measured for the candidates. The number of detected candidates range from 1 around M64 to 33 around NGC 4258. In total, 155 candidates are found, of which 93 are new. While we defer an analysis of the satellite luminosity functions of the hosts until distance information is available for the candidates, we do show that the candidates are primarily red, spheroidal systems with properties roughly consistent with known satellites in the Local Group.

Keywords: dwarf galaxies; astronomical methods; galaxy formation
The BLAST Observatory: A Sensitivity Study for Far-IR Balloon-borne Polarimeters

Sensitive wide-field observations of polarized thermal emission from interstellar dust grains will allow astronomers to address key outstanding questions about the life cycle of matter and energy driving the formation of stars and the evolution of galaxies. Stratospheric balloon-borne telescopes can map this polarized emission at far-infrared wavelengths near the peak of the dust thermal spectrum—wavelengths that are inaccessible from the ground. In this paper we address the sensitivity achievable by a Super Pressure Balloon polarimetry mission, using as an example the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) Observatory. By launching from Wanaka, New Zealand, the BLAST Observatory can obtain a 30 days flight with excellent sky coverage—overcoming limitations of past experiments that suffered from short flight duration and/or launch sites with poor coverage of nearby star-forming regions. This proposed polarimetry mission will map large regions of the sky at sub-arcminute resolution, with simultaneous observations at 175, 250, and 350 μm, using a total of 8274 microwave kinetic inductance detectors. Here, we describe the scientific motivation for the BLAST Observatory, the proposed implementation, and the forecasting methods used to predict its sensitivity. We also compare our forecasted experiment sensitivity with other facilities.

Keywords: high altitude balloons
Orbital Evolution of Binary Black Holes in Active Galactic Nucleus Disks: A Disk Channel for Binary Black Hole Mergers?

We perform a series of high-resolution 2D hydrodynamical simulations of equal-mass binary black holes (BBHs) embedded in active galactic nucleus (AGN) accretion disks to study whether these binaries can be driven to merger by the surrounding gas. We find that the gravitational softening adopted for the BBH has a profound impact on this result. When the softening is less than 10% of the binary separation, we show that, in agreement with recent simulations of isolated equal-mass binaries, prograde BBHs expand in time rather than contract. Eventually, however, the binary separation becomes large enough that the tidal force of the central AGN disrupts them. Only when the softening is relatively large do we find that prograde BBHs harden. We determine through detailed analysis of the binary torque, that this dichotomy is due to a loss of spiral structure in the circum-single disks orbiting each black hole when the softening is a significant fraction of the binary separation. Properly resolving these spirals—both with high resolution and small softening—results in a significant source of binary angular momentum. Only for retrograde BBHs do we find consistent hardening, regardless of softening, as these BBHs lack the important spiral structure in their circum-single disks. This suggests that the gas-driven inspiral of retrograde binaries can produce a population of compact BBHs in the gravitational-wave-emitting regime in AGN disks, which may contribute a large fraction to the observed BBH mergers.

Keywords: active galactic nuclei; black holes; black hole physics; gravitational wave sources; hydrodynamical simulations
Galactic Cirri at High Galactic Latitudes. I. Investigating Scatter in Slopes between Optical and Far-infrared Intensities

Based on the slopes between DESI g, r and Infrared Astronomical Satellite (IRAS) 100 μm intensities, specifically k g and k r , we have constructed a substantial sample of Galactic cirri. This sample covers 561.25 deg2 at high Galactic latitudes (∣b∣ ≥ 30°), allowing for a systematic study of the physical parameters of the Galactic cirrus on a large scale, such as g ‑ r color, dust temperature, asymmetry factor, and albedo. The ratio of k g and k r is consistent with the diffuse Galactic starlight model, suggesting that the diffuse starlight within our own Galaxy serves as the primary illumination source for the cirrus. Both k g and k r decrease slowly with increasing Galactic latitudes and IRAS 100 μm intensities, while they do not have a correlation with Galactic longitudes. The distribution of k g and k r confirms a significant scatter in the slopes, reaching a factor of 4–5. Such large scatter cannot be explained by the weak correlation between the slopes and Galactic latitudes and IRAS 100 μm intensities. Instead, it is attributed to substantial variations in the intrinsic properties of the dust, e.g., asymmetry factor and albedo. We propose that the properties of dust particles play a critical role in the observed scatter in slopes, making them the primary contributing factors. Moreover, the variations in dust properties within the cirrus are localized rather than exhibiting large-scale gradients.

Keywords: interstellar emissions; interstellar dust; interstellar medium; diffuse nebulae
Molecular Gas in 21 and 30 μm Sources: The 2 mm and 1.3 mm Spectra of IRAS 21318+5631 and 22272+5435

The carriers of the 21 and 30 μm emission features in infrared spectra of circumstellar envelopes are a long-standing enigma. In this paper, we present the results of molecular line observations toward two circumstellar envelopes exhibiting the 21 and/or 30 μm features, IRAS 21318+5631 and 22272+5435. We investigate whether they have unusual gas-phase chemistry and search for a possible gas-phase precursor of the carriers of the two dust features. The spectra cover several discrete frequency ranges of 130-164 GHz and 216.5-273 GHz, resulting in a detection of 13 molecular species and isotopologues in each object. A rotation-diagram analysis is carried out to determine the molecular abundances, column densities, and excitation temperatures. We did not discover any molecular species that would be unexpected in a normal C-rich star. Nevertheless, there exists subtle differences between their molecular abundances. IRAS 22272+5435 shows stronger SiC2 and HC3N lines and weaker SiS lines than IRAS 21318+5631, suggesting that this 21 μm source is more carbon-rich and has experienced more efficient dust formation. We discuss the potential implications of the results for the carriers of the 21 μm and 30 μm features.

Keywords: spectral line identification; circumstellar matter; interstellar molecules; asymptotic giant branch; post-asymptotic giant branch
Solar Coronal Mass Ejections Plasma Diagnostics Expressed as Potential Stellar CME Signatures

Solar coronal mass ejections (CMEs) have a strong association with solar flares that is not fully understood. This characteristic of our Sun's magnetic activity may also occur on other stars, but the lack of successfully detected stellar CMEs makes it difficult to perform statistical studies that might show a similar association between CMEs and flares. Because of the potentially strong association, the search for stellar CMEs often starts with a successful search for superflares on magnetically active stars. Regardless of the flare's presence, we emphasize the utility of searching for CME-specific spectroscopic signatures when attempting to find and confirm stellar CME candidates. We use solar CMEs as examples of why a multitude of ultraviolet emission lines, when detected simultaneously, can substantially improve the credibility of spectroscopically discovered stellar CME candidates. We make predictions on how bright CME-related emission lines can be if they are derived from distant stars. We recommend the use of three emission lines in particular (C IV 1550 Å, O VI 1032 Å, and C III 977 Å) due to their potentially bright signal and convenient diagnostic capabilities that can be used to confirm if an observational signature truly derives from a stellar CME.

Keywords: stellar coronal mass ejections; stellar phenomena; solar coronal mass ejections
The Role of Early Giant-planet Instability in Terrestrial Planet Formation

The terrestrial planets are believed to have formed by violent collisions of tens of lunar- to Mars-size protoplanets at time t < 200 Myr after the protoplanetary gas disk dispersal (t0). The solar system giant planets rapidly formed during the protoplanetary disk stage and, after t0, radially migrated by interacting with outer disk planetesimals. An early (t < 100 Myr) dynamical instability is thought to have occurred with Jupiter having gravitational encounters with a planetary-size body, jumping inward by ∼0.2-0.5 au, and landing on its current, mildly eccentric orbit. Here we investigate how the giant-planet instability affected the formation of the terrestrial planets. We study several instability cases that were previously shown to match many solar system constraints. We find that resonances with giant planets help to remove solids available for accretion near ∼1.5 au, thus stalling the growth of Mars. It does not matter, however, whether the giant planets are placed on their current orbits at t0 or whether they realistically evolve in one of our instability models; the results are practically the same. The tight orbital spacing of Venus and Earth is difficult to reproduce in our simulations, including cases where bodies grow from a narrow annulus at 0.7-1 au, because protoplanets tend to spread radially during accretion. The best results are obtained in the narrow-annulus model when protoplanets emerging from the dispersing gas nebula are assumed to have (at least) the mass of Mars. This suggests efficient accretion of the terrestrial protoplanets during the first ∼10 Myr of the solar system.

Keywords: solar system terrestrial planets; planetary system formation
SKYSURF-4: Panchromatic Hubble Space Telescope All-Sky Surface-brightness Measurement Methods and Results

The diffuse, unresolved sky provides most of the photons that the Hubble Space Telescope (HST) receives, yet remains poorly understood. The HST Archival Legacy program SKYSURF aims to measure the 0.2-1.6 μm sky surface brightness (sky-SB) from over 140,000 HST images. We describe a sky-SB measurement algorithm designed for SKYSURF that is able to recover the input sky-SB from simulated images to within 1% uncertainty. We present our sky-SB measurements estimated using this algorithm on the entire SKYSURF database. Comparing our sky-SB spectral energy distribution (SED) to measurements from the literature shows general agreements. Our SKYSURF SED also reveals a possible dependence on the Sun angle, indicating either nonisotropic scattering of solar photons off interplanetary dust or an additional component to zodiacal light. Finally, we update the diffuse light limits in the near-IR based on the methods from Carleton et al., with values of 0.009 MJy sr-1 (22 nW m-2 sr-1) at 1.25 μm, 0.015 MJy sr-1 (32 nW m-2 sr-1) at 1.4 μm, and 0.013 MJy sr-1 (25 nW m-2 sr-1) at 1.6 μm. These estimates provide the most stringent all-sky constraints to date in this wavelength range. SKYSURF sky-SB measurements are made public on the official SKYSURF website and will be used to constrain diffuse light in future papers.

Keywords: zodiacal cloud; hubble space telescope; sky brightness; cosmic background radiation; optical astronomy
Sizes and Mass Profiles of Candidate Massive Galaxies Discovered by JWST at 7 < z < 9: Evidence for Very Early Formation of the Central 100 pc of Present-day Ellipticals

The first JWST data revealed an unexpected population of red galaxies that appear to have redshifts of z ~ 7-9 and high masses of M * ≳ 1010 M ☉. Here we fit Sérsic profiles to the F200W NIRCam images of the 13 massive galaxy candidates of Labbé et al., to determine their structural parameters. Satisfactory fits were obtained for nine galaxies. We find that their effective radii are extremely small, ranging from r e ~ 80 pc to r e ~ 300 pc, with a mean of <r e> ≈ 150 pc. For their apparent stellar masses, the galaxies are smaller than any other galaxy population that has been observed at any other redshift. We use the fits to derive circularized three-dimensional stellar mass profiles of the galaxies, and compare these to the mass profiles of massive quiescent galaxies at z ~ 2.3 and nearby elliptical galaxies. Despite the fact that the high-redshift galaxies have 10-20 times smaller half-light radii than their putative descendants, the central stellar densities are very similar. The most straightforward interpretation is that the dense compact inner regions of the most massive ellipticals today were already in place ~600 Myr after the Big Bang. We caution that the redshifts and masses of the galaxies remain to be confirmed, and that the complex NIRCam point-spread function is not yet fully characterized.

Keywords: galaxy evolution; high-redshift galaxies; james webb space telescope