adsabs/SciX_UAT_keywords huggingface dataset:
NEMESIS: Exoplanet Transit Survey of Nearby M-dwarfs in TESS FFIs. I.

In this work, we present an analysis of 33,054 M-dwarf stars, located within 100 parsecs, via the Transiting Exoplanet Survey Satellite (TESS) full-frame images (FFIs) of observed sectors 1-5. We present a new pipeline called NEMESIS, developed to extract detrended photometry, and to perform transit searches of single-sector data in TESS FFIs. As many M-dwarfs are faint, and are not observed with a two-minute cadence by TESS, FFI transit surveys can provide an empirical validation of how many planets are missed, using the 30-minute cadence data. In this work, we detect 183 threshold crossing events, and present 29 candidate planets for sectors 1-5, 24 of which are new detections. Our sample contains orbital periods ranging from 1.25 to 6.84 days, and planetary radii from 1.26 to 5.31 R⊕. With the addition of our new planet candidate detections, along with detections previously observed in sectors 1-5, we calculate an integrated occurrence rate of 2.49 ± 1.58 planets per star, for the period range ∈ [1, 9] days, and planet radius range ∈ [0.5,11] R⊕. We project an estimated yield of 122 ± 11 transit detections of nearby M-dwarfs. Of our new candidates, 23 have signal-to-noise ratios >7, transmission spectroscopy metrics >38, and emission spectroscopy metrics >10. We present all of our data products for our planet candidates via the Filtergraph data visualization service, located at https://filtergraph.com/NEMESIS.

Keywords: exoplanet astronomy; exoplanet detection methods; m dwarf stars; transit photometry; m stars
A Magnetohydrodynamic Relaxation Method for Non-force-free Magnetic Field in Magnetohydrostatic Equilibrium

A nonlinear force-free field (NLFFF) extrapolation is widely used to reconstruct the three-dimensional magnetic field in the solar corona from the observed photospheric magnetic field. However, the pressure gradient and gravitational forces are ignored in the NLFFF model, even though the photospheric and chromospheric magnetic fields are not in general force-free. Here we develop a magnetohydrodynamic (MHD) relaxation method that reconstructs the solar atmospheric (chromospheric and coronal) magnetic field as a non-force-free magnetic field (NFFF) in magnetohydrostatic equilibrium where the Lorentz, pressure gradient, and gravitational forces are balanced. The system of basic equations for the MHD relaxation method is derived, and mathematical properties of the system are investigated. A robust numerical solver for the system is constructed based on the modern high-order shock capturing scheme. Two-dimensional numerical experiments that include the pressure gradient and gravitational forces are also demonstrated.

Keywords: solar magnetic fields; solar corona; solar chromosphere; solar photosphere; solar atmosphere; solar coronal loops
Evidence for the Operation of the Hanle and Magneto-optical Effects in the Scattering Polarization Signals Observed by CLASP2 across the Mg II h and k Lines

Radiative transfer investigations of the solar Mg II h and k resonance lines around 280 nm have shown that, while their circular polarization (Stokes V) signals arise from the Zeeman effect, the linear polarization profiles (Stokes Q and U) are dominated by the scattering of anisotropic radiation and the Hanle and magneto-optical (MO) effects. Using the unprecedented observations of the Mg II and Mn I resonance lines obtained by the Chromospheric LAyer Spectro-Polarimeter (CLASP2), here we investigate how the linear polarization signals at different wavelengths (i.e., at the center, and at the near and far wings of the k line) vary with the longitudinal component of the magnetic field (B L ) at their approximate height of formation. The B L is estimated from the V signals in the aforementioned spectral lines. Particular attention is given to the following quantities that are expected to be influenced by the presence of magnetic fields through the Hanle and MO effects: the sign of the U signals, the total linear polarization amplitude (LP) and its direction (χ) with respect to a reference direction. We find that at the center and near wings of the k line, the behavior of these quantities is significantly different in the observed quiet and plage regions, and that both LP and χ seem to depend on B L . These observational results are indicative of the operation of the Hanle effect at the center of the k line and of the MO effects at the near wings of the k line.

Keywords: solar physics; solar magnetic fields; spectropolarimetry; polarimetry
The Mercury's Bow-shock Models Near Perihelion and Aphelion

When Mercury moves in its high-eccentricity orbit around the Sun, the background solar wind conditions are significantly changed. We investigated the effects of heliocentric distance and interplanetary magnetic field (IMF) orientation on the shape and location of Mercury's bow shock. We fit empirical models to the bow shock crossings obtained from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging magnetometer observations under different conditions. Our results demonstrate that the bow shock moves antiplanetward when Mercury moves from perihelion to aphelion. However, this difference is not as significant as that of magnetopause due to the thickness variation of the magnetosheath. The IMF orientations show a weak influence on the bow shock shape and location, which implies that the southward magnetic field component is not the determinant factor that drives reconnection at the low-β magnetopause of Mercury.

Keywords: magnetic fields; planetary magnetospheres; mercury (planet); planetary bow shocks; solar wind
Bayesian Survey of the Dense Matter Equation of State Built upon Skyrme Effective Interactions

The nonrelativistic model of nuclear matter (NM) with zero-range Skyrme interactions is employed within a Bayesian approach in order to study the behavior of the neutron star (NS) equation of state (EOS). A minimal number of constraints from nuclear physics and ab initio calculations of pure neutron matter (PNM) are imposed together with causality and a lower limit on the maximum mass of an NS to all our models. Our key result is that accounting for correlations among the values that the energy per neutron in PNM takes at various densities and that are typically disregarded efficiently constrains the behavior of the EOS at high densities. A series of global NS properties, e.g., maximum mass, central density of the maximum mass configuration, minimum NS mass that allows for direct URCA, and radii of intermediate and massive NSs, appear to be correlated with the value of effective neutron mass in PNM at 0.16 fm‑3. Together with similar studies in the literature our work contributes to a better understanding of the NS EOS as well as its link with the properties of dense NM.

Keywords: nuclear physics; nuclear astrophysics; neutron star cores; neutron stars
Does a Solar Filament Barb Always Correspond to a Prominence Foot?

Solar filaments are dark structures on the solar disk, with an elongated spine and several barbs extending out from the spine. When appearing above the solar limb, a filament is called a prominence, with several feet extending down to the solar surface. It was generally thought that filament barbs are simply the prominence feet veering away from the spine and down to the solar surface. However, it was recently noticed that there might be another dynamic type of barb, which was proposed to be due to filament thread longitudinal oscillation. If this is the case, the dynamic barbs would not extend down to the solar surface. With the quadrature observations of a filament barb on 2011 June 5 from the Solar Dynamics Observatory and the Solar Terrestrial Relations Observatory satellites, we confirm that the filament barb is due to filament thread longitudinal oscillations. Viewed from the side, the filament barb looks like an appendix along the spine of the prominence and does not extend down to the solar surface as a foot.

Keywords: solar filaments; solar prominences; solar magnetic fields
Discovery of an Accretion Streamer and a Slow Wide-angle Outflow around FU Orionis

We present Atacama Large Millimeter/submillimeter Array 12-m, 7-m, and Total Power Array observations of the FU Orionis outbursting system, covering spatial scales ranging from 160 to 25,000 au. The high-resolution interferometric data reveal an elongated 12CO(2–1) feature previously observed at lower resolution in 12CO(3–2). Kinematic modeling indicates that this feature can be interpreted as an accretion streamer feeding the binary system. The mass infall rate provided by the streamer is significantly lower than the typical stellar accretion rates (even in quiescent states), suggesting that this streamer alone is not massive enough to sustain the enhanced accretion rates characteristic of the outbursting class prototype. The observed streamer may not be directly linked to the current outburst, but rather a remnant of a previous, more massive streamer that may have contributed enough to the disk mass to render it unstable and trigger the FU Orionis outburst. The new data detect, for the first time, a vast, slow-moving carbon monoxide molecular outflow emerging from this object. To accurately assess the outflow properties (mass, momentum, and kinetic energy), we employ 13CO(2–1) data to correct for optical depth effects. The analysis indicates that the outflow corresponds to swept-up material not associated with the current outburst, similar to the slow molecular outflows observed around other FUor and Class I protostellar objects.

Keywords: star formation; fu orionis stars; young stellar objects
Tracking Halo Orbits and Their Mass Evolution around Large-scale Filaments

We have explored the dynamical and mass evolution of halos driven by large-scale filaments using a dark-matter-only cosmological simulation with the help of a phase-space analysis. Since a nonnegligible number of galaxies are expected to fall into the cluster environment through large-scale filaments, tracking how halos move around large-scale filaments can provide a more comprehensive view on the evolution of cluster galaxies. Halos exhibit orbital motions around filaments, which emerge as specific trajectories in a phase space composed of halos' perpendicular distance and velocity component with respect to filaments. These phase-space trajectories can be represented by three cases according to their current states. We parameterize the trajectories with halos' initial position and velocity, maximum velocity, formation time, and time since first crossing, which are found to be correlated with each other. These correlations are explained well in the context of the large-scale structure formation. The mass evolution and dynamical properties of halos seem to be affected by the density of filaments, which can be shown from the fact that halos around denser filaments are more likely to lose their mass and be bound within large-scale filaments. Finally, we reproduce the mass segregation trend around filaments found in observations. The mass segregation has been developed because halos that formed earlier approached filaments earlier, grew efficiently, and ended up being more massive. We also found that dynamical friction helps to retain this segregation trend.

Keywords: large-scale structure of the universe; galaxy dark matter halos; cosmic web
Three Ultra-short-period Contact Eclipsing Binary Systems Mined from Massive Astronomical Surveys

We present the photometric analysis of three ultra-short-period total eclipsing binaries in contact configuration, CRTS_J172718.0+431624, OGLE-BLG-ECL-000104, and OGLE-BLG-ECL-000012, mined from massive astronomical surveys. Using the available archival light curves (LCs) from Vista Variables in the Vía Láctea (VVV), Optical Gravitational Lensing Experiment (OGLE), Zwicky Transient Facility, and Catalina Sky Survey in different passbands and new multiband photometric observations with the 2.3 m Aristarchos telescope at Helmos Observatory, their relative physical parameters were derived. We explored the parameter space by using the PIKAIA genetic algorithm optimizer. The best photometric solution and error budget estimation were adopted for each system through Markov Chain Monte Carlo sampling of the global optimum. The approximate absolute parameters were derived for each contact system adopting an empirical mass-luminosity relation. All three systems have a mass ratio lower than 0.5. The exchange between the primary and secondary depths of CRTS_J172718.0+431624 during 2016-2022 may be due to spot activity. In addition, we present a detailed analysis of the first well-characterized shortest-period contact eclipsing binary with total eclipses known so far (OGLE-BLG-ECL-000104). Thanks to VVV and OGLE LCs, new distances were derived for OGLE-BLG-ECL-000104 and OGLE-BLG-ECL-000012 using empirical period-luminosity relations. The origin and evolutionary status of all three ultra-short-period contact binaries are thoroughly discussed in the context of the detached binary formation channel.

Keywords: eclipsing binary stars; contact binary stars; fundamental parameters of stars; astronomy data analysis
Molecular Clouds Surrounding Supernova Remnant G43.9+1.6: Associated and Nonassociated

Many supernova remnants (SNRs) are considered to evolve in molecular environments, but the associations between SNRs and molecular clouds (MCs) are often unclear. Being aware of such ambiguity, in our study, we report on the molecular environment toward SNR G43.9+1.6 through CO line observations. We investigated the correlations between the SNR and MCs at different velocities, and found two velocity components, i.e., ∼5 km s-1 and ∼50 km s-1, showing spatial correlations with the remnant. However, no kinematic evidence of a disturbance was found for the ∼5 km s-1 velocity component. Furthermore, at the distance of the ∼5 km s-1 velocity component, either near or far, the derived physical parameters are unreasonable. We conclude that the SNR is not associated with the ∼5 km s-1 velocity component, and their spatial correlation is just a chance correlation. For the ∼50 km s-1 velocity component, kinematic evidence of disturbances, as well as the spatial correlation, indicate that it is associated with the SNR. We found that all the CO spectra extracted from the molecular clumps distributed along the border of the remnant are with broadened components presented, which can be fitted by Gaussian functions. Through further analysis, we suggest that the SNR is at a near kinematic distance of about 3.1 kpc.

Keywords: supernova remnants; radio spectroscopy; interstellar dynamics; interstellar line emission; interstellar medium; interstellar molecules; stellar-interstellar interactions; molecular clouds; millimeter astronomy
Nozzle Shocks, Disk Tearing, and Streamers Drive Rapid Accretion in 3D GRMHD Simulations of Warped Thin Disks

The angular momentum of gas feeding a black hole (BH) may be misaligned with respect to the BH spin, resulting in a tilted accretion disk. Rotation of the BH drags the surrounding spacetime, manifesting as Lense-Thirring torques that lead to disk precession and warping. We study these processes by simulating a thin (H/r = 0.02), highly tilted ( ${ \mathcal T }=65^\circ $ ) accretion disk around a rapidly rotating (a = 0.9375) BH at extremely high resolutions, which we performed using the general-relativistic magnetohydrodynamic code H-AMR. The disk becomes significantly warped and continuously tears into two individually precessing subdisks. We find that mass accretion rates far exceed the standard α-viscosity expectations. We identify two novel dissipation mechanisms specific to warped disks that are the main drivers of accretion, distinct from the local turbulent stresses that are usually thought to drive accretion. In particular, we identify extreme scale height oscillations that occur twice an orbit throughout our disk. When the scale height compresses, "nozzle" shocks form, dissipating orbital energy and driving accretion. Separate from this phenomenon, there is also extreme dissipation at the location of the tear. This leads to the formation of low-angular momentum "streamers" that rain down onto the inner subdisk, shocking it. The addition of low-angular momentum gas to the inner subdisk causes it to rapidly accrete, even when it is transiently aligned with the BH spin and thus unwarped. These mechanisms, if general, significantly modify the standard accretion paradigm. Additionally, they may drive structural changes on much shorter timescales than expected in α-disks, potentially explaining some of the extreme variability observed in active galactic nuclei.

Keywords: black holes; accretion; general relativity; magnetohydrodynamics; astronomical simulations
Radio Spectral Index Analysis of Southern Hemisphere Symbiotic Stars

Symbiotic stars show emission across the electromagnetic spectrum from a wide array of physical processes. At centimeter waves, both synchrotron and thermal emissions are seen, often highly variable and associated with outbursts in the optical and X-rays. Most models of the radio emission include an ionized region within the dense wind of the red giant star that is kept ionized by activity on the white dwarf companion or its accretion disk. In some cases, there is ongoing shell burning on the white dwarf due to its high mass accretion rate or a prior nova eruption; in other cases, nuclear fusion occurs only occasionally as recurrent nova events. In this study, we measure the spectral indices of a sample of symbiotic systems in the Southern Hemisphere using the Australia Telescope Compact Array. Putting our data together with results from other surveys, we derive the optical depths and brightness temperatures of some well-known symbiotic stars. Using parallax distances from Gaia Data Release 3, we determine the sizes and characteristic electron densities in the radio emission regions. The results show a range of a factor of 104 in radio luminosity and a factor of 100 in linear size. These numbers are consistent with a picture where the rate of shell burning on the white dwarf determines the radio luminosity. Therefore, our findings also suggest that radio luminosity can be used to determine whether a symbiotic star is powered by accretion alone or also by shell burning.

Keywords: symbiotic binary stars; stellar accretion disks; white dwarf stars; interacting binary stars
Characteristics of an Extreme Dusty Star-forming Galaxy at z = 4.5

We present new physical properties for an extreme (LIR > 1013 L⊙), unlensed dusty star-forming galaxy at z = 4.531, G09-81106. We compile fluxes from the literature, and include new Hubble Space Telescope data to generate SED models under various assumptions. G09-81106 has a number of physical characteristics that far surpass the average data for DSFGs, including high dust temperature (∼70 K) and star formation rate ( > 2 × 103 M⊙ yr-1). While barely within the average star-forming main sequence region, G09 is already an order of magnitude more massive and more star-forming than most star-forming galaxies at similar epochs. Visual inspection suggests these exceptional properties may be due to an ongoing merger, though future work with spatially resolved imaging and spectroscopic analysis will reveal its true nature.

Keywords: ultraluminous infrared galaxies; high-redshift galaxies; galaxy evolution; starburst galaxies
Mapping Obscuration to Reionization with ALMA (MORA): 2 mm Efficiently Selects the Highest-redshift Obscured Galaxies

We present the characteristics of 2 mm selected sources from the largest Atacama Large Millimeter/submillimeter Array (ALMA) blank-field contiguous survey conducted to date, the Mapping Obscuration to Reionization with ALMA (MORA) survey covering 184 arcmin2 at 2 mm. Twelve of 13 detections above 5σ are attributed to emission from galaxies, 11 of which are dominated by cold dust emission. These sources have a median redshift of $\langle {z}_{2\,\mathrm{mm}}\rangle ={3.6}_{-0.3}^{+0.4}$ primarily based on optical/near-infrared photometric redshifts with some spectroscopic redshifts, with 77% ± 11% of sources at z > 3 and 38% ± 12% of sources at z > 4. This implies that 2 mm selection is an efficient method for identifying the highest-redshift dusty star-forming galaxies (DSFGs). Lower-redshift DSFGs (z < 3) are far more numerous than those at z > 3 yet are likely to drop out at 2 mm. MORA shows that DSFGs with star formation rates in excess of 300 M ⊙ yr-1 and a relative rarity of ~10-5 Mpc-3 contribute ~30% to the integrated star formation rate density at 3 < z < 6. The volume density of 2 mm selected DSFGs is consistent with predictions from some cosmological simulations and is similar to the volume density of their hypothesized descendants: massive, quiescent galaxies at z > 2. Analysis of MORA sources' spectral energy distributions hint at steeper empirically measured dust emissivity indices than reported in typical literature studies, with $\langle \beta \rangle ={2.2}_{-0.4}^{+0.5}$ . The MORA survey represents an important step in taking census of obscured star formation in the universe's first few billion years, but larger area 2 mm surveys are needed to more fully characterize this rare population and push to the detection of the universe's first dusty galaxies.

Keywords: millimeter astronomy; submillimeter astronomy; dust continuum emission; high-redshift galaxies; active galaxies; infrared galaxies; starburst galaxies
X-Ray Binary Luminosity Function Scaling Relations in Elliptical Galaxies: Evidence for Globular Cluster Seeding of Low-mass X-Ray Binaries in Galactic Fields

We investigate X-ray binary (XRB) luminosity function (XLF) scaling relations for Chandra-detected populations of low-mass XRBs (LMXBs) within the footprints of 24 early-type galaxies. Our sample includes Chandra and Hubble Space Telescope observed galaxies at $D\lesssim 25$ Mpc that have estimates of the globular cluster (GC) specific frequency (SN) reported in the literature. As such, we are able to directly classify X-ray-detected sources as being coincident with unrelated background/foreground objects, GCs, or sources that are within the fields of the galaxy targets. We model the GC and field LMXB population XLFs for all galaxies separately and then construct global models characterizing how the LMXB XLFs vary with galaxy stellar mass and SN. We find that our field LMXB XLF models require a component that scales with SN and has a shape consistent with that found for the GC LMXB XLF. We take this to indicate that GCs are "seeding" the galactic field LMXB population, through the ejection of GC LMXBs and/or the diffusion of the GCs in the galactic fields themselves. However, we also find that an important LMXB XLF component is required for all galaxies that scales with stellar mass, implying that a substantial population of LMXBs are formed "in situ," which dominates the LMXB population emission for galaxies with SN ≲ 2. For the first time, we provide a framework quantifying how directly associated GC LMXBs, GC-seeded LMXBs, and in situ LMXBs contribute to LMXB XLFs in the broader early-type galaxy population.

Keywords: elliptical galaxies; early-type galaxies; x-ray binary stars; low-mass x-ray binary stars; globular star clusters; x-ray point sources