Sazuna/UAT_keywords huggingface dataset:
Circumbinary Disk Evolution in the Presence of an Outer Companion Star. We consider a hierarchical triple system consisting of an inner eccentric binary with an outer companion. A highly misaligned circumbinary disk around the inner binary is subject to two competing effects: (i) nodal precession about the inner binary eccentricity vector that leads to an increase in misalignment (polar alignment) and (ii) Kozai-Lidov (KL) oscillations of eccentricity and inclination driven by the outer companion that leads to a reduction in the misalignment. The outcome depends upon the ratio of the timescales of these effects. If the inner binary torque dominates, then the disk aligns to a polar orientation. If the outer companion torque dominates, then the disk undergoes KL oscillations. In that case, the highly eccentric and misaligned disk is disrupted and accreted by the inner binary, while some mass is transferred to the outer companion. However, when the torques are similar, the outer parts of the circumbinary disk can undergo large eccentricity oscillations while the inclination remains close to polar orientation. The range of initial disk inclinations that evolve to a polar orientation is smaller in the presence of the outer companion. Disk breaking is also more likely, at least temporarily, during the polar alignment process. The stellar orbits in HD 98800 have parameters such that polar alignment of the circumbinary disk is expected. In the absence of gas, solid particles are unstable at much smaller radii than the gas-disk inner tidal truncation radius because KL-driven eccentricity leads to close encounters with the binary.

Keywords: Accretion, Binary stars, Hydrodynamics, Protoplanetary disks, Circumstellar disks, Stellar accretion disks, Trinary stars, Exoplanet formation, Planet formation
Magnetocentrifugal Origin for Protostellar Jets Validated through Detection of Radial Flow at the Jet Base. Jets can facilitate the mass accretion onto the protostars in star formation. They are believed to be launched from accretion disks around the protostars by magnetocentrifugal force, as supported by the detections of rotation and magnetic fields in some of them. Here we report a radial flow of the textbook-case protostellar jet HH 212 at the base to further support this jet-launching scenario. This radial flow validates a central prediction of the magnetocentrifugal theory of jet formation and collimation, namely, the jet is the densest part of a wide-angle wind that flows radially outward at distances far from the (small, sub-au) launching region. Additional evidence for the radially flowing wide-angle component comes from its ability to reproduce the structure and kinematics of the shells detected around the HH 212 jet. This component, which can transport material from the inner to outer disk, could account for the chondrules and Ca-Al-rich inclusions detected in the solar system at large distances.

Keywords: Jets, Star formation, Interstellar medium
NGC 5846-UDG1: A Galaxy Formed Mostly by Star Formation in Massive, Extremely Dense Clumps of Gas. It has been shown that ultra-diffuse galaxies (UDGs) have higher specific frequencies of globular clusters, on average, than other dwarf galaxies with similar luminosities. The UDG NGC 5846-UDG1 is among the most extreme examples of globular cluster-rich galaxies found so far. Here we present new Hubble Space Telescope observations and analysis of this galaxy and its globular cluster system. We find that NGC 5846-UDG1 hosts 54 ± 9 globular clusters, three to four times more than any previously known galaxy with a similar luminosity and higher than reported in previous studies. With a galaxy luminosity of L  V,gal ≈ 6 × 107 L ⊙ (M ⋆ ≈ 1.2 × 108 M ⊙) and a total globular cluster luminosity of L  V,GCs ≈ 7.6 × 106 L ⊙, we find that the clusters currently comprise ~13% of the total light. Taking into account the effects of mass loss from clusters during their formation and throughout their lifetime, we infer that most of the stars in the galaxy likely formed in globular clusters, and very little to no "normal" low-density star formation occurred. This result implies that the most extreme conditions during early galaxy formation promoted star formation in massive and dense clumps, in contrast to the dispersed star formation observed in galaxies today.

Keywords: Globular star clusters, Observational astronomy, Galaxy formation, Hubble Space Telescope, Dwarf galaxies, HST photometry, Star clusters, Star formation, Low surface brightness galaxies
ALMA as a Prominence Thermometer: First Observations. We present first prominence observations obtained with Atacama Large Millimeter Array (ALMA) in Band 3 at the wavelength of 3 mm. High-resolution observations have been coaligned with the MSDP Hα data from Wrocław-Białków large coronagraph at similar spatial resolution. We analyze one particular cotemporal snapshot, first calibrating both ALMA and MSDP data and then demonstrating a reasonable correlation between both. In particular, we can see quite similar fine-structure patterns in both ALMA brightness-temperature maps and MSDP maps of Hα intensities. Using ALMA, we intend to derive the prominence kinetic temperatures. However, having current observations only in one band, we use an independent diagnostic constraint, which is the Hα line integrated intensity. We develop an inversion code and show that it can provide realistic temperatures for brighter parts of the prominence where one gets a unique solution, while within faint structures, such inversion is ill conditioned. In brighter parts, ALMA serves as a prominence thermometer, provided that the optical thickness in Band 3 is large enough. In order to find a relation between brightness and kinetic temperatures for a given observed Hα intensity, we constructed an extended grid of non-LTE prominence models covering a broad range of prominence parameters. We also show the effect of the plane-of-sky filling factor on our results.

Keywords: Solar prominences
The Case for Technosignatures: Why They May Be Abundant, Long-lived, Highly Detectable, and Unambiguous. The intuition suggested by the Drake equation implies that technology should be less prevalent than biology in the galaxy. However, it has been appreciated for decades in the SETI community that technosignatures could be more abundant, longer-lived, more detectable, and less ambiguous than biosignatures. We collect the arguments for and against technosignatures' ubiquity and discuss the implications of some properties of technological life that fundamentally differ from nontechnological life in the context of modern astrobiology: It can spread among the stars to many sites, it can be more easily detected at large distances, and it can produce signs that are unambiguously technological. As an illustration in terms of the Drake equation, we consider two Drake-like equations, for technosignatures (calculating N(tech)) and biosignatures (calculating N(bio)). We argue that Earth and humanity may be poor guides to the longevity term L and that its maximum value could be very large, in that technology can outlive its creators and even its host star. We conclude that while the Drake equation implies that N(bio) ≫ N(tech), it is also plausible that N(tech) ≫ N(bio). As a consequence, as we seek possible indicators of extraterrestrial life, for instance, via characterization of the atmospheres of habitable exoplanets, we should search for both biosignatures and technosignatures. This exercise also illustrates ways in which biosignature and technosignature searches can complement and supplement each other and how methods of technosignature search, including old ideas from SETI, can inform the search for biosignatures and life generally.

Keywords: Biosignatures, Search for extraterrestrial intelligence, Technosignatures, Astrobiology
Gaia 0007-1605: An Old Triple System with an Inner Brown Dwarf-White Dwarf Binary and an Outer White Dwarf Companion. We identify Gaia 0007-1605 A,C as the first inner brown dwarf-white dwarf binary of a hierarchical triple system in which the outer component is another white dwarf (Gaia 0007-1605 B). From optical/near-infrared spectroscopy obtained at the Very Large Telescope with the X-Shooter instrument and/or from Gaia photometry plus spectral energy distribution fitting, we determine the effective temperatures and masses of the two white dwarfs (12,018 ± 68 K and 0.54 ± 0.01 M ☉ for Gaia 0007-1605 A and 4445 ± 116 K and 0.56 ± 0.05 M ☉ for Gaia 0007-1605 B) and the effective temperature of the brown dwarf (1850 ± 50 K; corresponding to spectral type L3 ± 1). By analyzing the available TESS light curves of Gaia 0007-1605 A,C we detect a signal at 1.0446 ± 0.0015 days with an amplitude of 6.25 ppt, which we interpret as the orbital period modulated from irradiation effects of the white dwarf on the brown dwarf's surface. This drives us to speculate that the inner binary evolved through a common-envelope phase in the past. Using the outer white dwarf as a cosmochronometer and analyzing the kinematic properties of the system, we conclude that the triple system is about 10 Gyr old.

Keywords: Trinary stars, White dwarf stars, Brown dwarfs
The Kiloparsec-scale Neutral Atomic Carbon Outflow in the Nearby Type 2 Seyfert Galaxy NGC 1068: Evidence for Negative AGN Feedback. Active galactic nucleus (AGN) feedback is postulated as a key mechanism for regulating star formation within galaxies. Studying the physical properties of the outflowing gas from AGNs is thus crucial for understanding the coevolution of galaxies and supermassive black holes. Here we report 55 pc resolution ALMA neutral atomic carbon [C I] 3 P 1-3 P 0 observations toward the central 1 kpc of the nearby Type 2 Seyfert galaxy NGC 1068, supplemented by 55 pc resolution CO(J = 1-0) observations. We find that [C I] emission within the central kiloparsec is strongly enhanced by a factor of &gt;5 compared to the typical [C I]/CO intensity ratio of ~0.2 for nearby starburst galaxies (in units of brightness temperature). The most [C I]-enhanced gas (ratio &gt; 1) exhibits a kiloparsec-scale elongated structure centered at the AGN that matches the known biconical ionized gas outflow entraining molecular gas in the disk. A truncated, decelerating bicone model explains well the kinematics of the elongated structure, indicating that the [C I] enhancement is predominantly driven by the interaction between the ISM in the disk and the highly inclined ionized gas outflow (which is likely driven by the radio jet). Our results strongly favor the "CO dissociation scenario" rather than the "in situ C formation" one, which prefers a perfect bicone geometry. We suggest that the high-[C I]/CO intensity ratio gas in NGC 1068 directly traces ISM in the disk that is currently dissociated and entrained by the jet and the outflow, i.e., the "negative" effect of the AGN feedback.

Keywords: Molecular gas, Interstellar phases, Interstellar atomic gas, Galaxy nuclei, Seyfert galaxies, Active galactic nuclei, Galaxy winds
Detection of the S(1) Rotational Line of H<SUB>2</SUB> toward IRC+10216: A Simultaneous Measurement of the Mass-loss Rate and CO Abundance. We report the first detection of the S(1) pure rotational line of ortho-H2 at 17.04 μm in an asymptotic giant branch star, using observations of IRC+10216 with the Echelon-cross-echelle Spectrograph (EXES) mounted on the Stratospheric Observatory for Infrared Astronomy. This line, which was observed in a very high-sensitivity spectrum (rms noise ≃0.04% of the continuum), was detected in the wing of a strong telluric line and displayed a P Cygni profile. The spectral ranges around the frequencies of the S(5) and S(7) ortho-H2 transitions were observed as well but no feature was detected in spectra with sensitivities of 0.12% and 0.09% regarding the continuum emission, respectively. We used a radiation transfer code to model these three lines and derived a mass-loss rate of (2.43 ± 0.21) × 10-5 M ⊙ yr-1 without using the CO abundance. The comparison of this rate with previous estimates derived from CO observations suggests that the CO abundance relative to H2 is (6.7 ± 1.4) × 10-4. From this quantity and previously reported molecular abundances, we estimate the O/H and C/H ratios to be (3.3 ± 0.7) × 10-4 and &gt;(5.2 ± 0.9) × 10-4, respectively. The C/O ratio is &gt;1.5 ± 0.4. The absence of the S(5) and S(7) lines of ortho-H2 in our observations can be explained by the opacity of hot dust within 5 R ⋆ from the center of the star. We estimate the intensity of the S(0) and S(2) lines of para-H2 to be ≃0.1% and 0.2% of the continuum, respectively, which are below the detection limit of EXES.

Keywords: High resolution spectroscopy, Spectral line identification, Carbon stars, Chemical abundances, Stellar mass loss, Infrared astronomy, Circumstellar matter, Asymptotic giant branch stars, Stellar winds, Dust continuum emission
Gradual Sequestration of Water at Lunar Polar Conditions due to Temperature Cycles. Migration of water molecules into the porous lunar soil can lead to sequestration of adsorbed water or ice at depth. Here, this process is modeled at several potential landing sites in the south polar region of the Moon. Desorption times are parameterized based on the Brunauer-Emmett-Teller (BET) isotherm model. Water sequestration is significant at depths where subsurface temperatures remain below the cold-trapping threshold, a condition satisfied at one of three sites considered, west of Haworth Crater. Model calculations predict a hydrated layer below a desiccated layer. The thickness of the desiccated layer is on the scale of the thermal skin depth, which for dust is typically centimeters. The underlying layer, decimeters thick, can be hydrated over a timescale of a billion years, reaching abundances on the order of 1 wt%. This sequestration process potentially simultaneously explains excess hydrogen concentrations outside of cold traps and the observed presence of a desiccated layer above a hydrogenous layer.

Keywords: Ice formation, The Moon, Lunar science, Lunar surface, Surface ices
Possible TeV Gamma-Ray Binary Origin of HESS J1828-099. The High Energy Stereoscopic System (H.E.S.S.) observatory has carried out a deep survey of the Galactic plane, in the course of which the existence of a significant number of (~78) TeV γ-ray sources was confirmed, many of which remain unidentified. HESS J1828-099 is a point-like (Gaussian standard deviation &lt; 0.°07) unidentified source among the 17 confirmed point-like sources in the H.E.S.S. Galactic Plane Survey (HGPS) catalog. This source is also unique because it does not seem to have any apparent association with any object detected at other wavelengths. We investigate the nature and association of HESS J1828-099 with multiwavelength observational data. A high-mass X-ray binary (HMXB)-composed of the pulsar XTE J1829-098 and a companion Be star-has been observed earlier in the X-ray and infrared bands, 14' away from HESS J1828-099. With 12 yr of Fermi-LAT γ-ray data, we explore the possibility of 4FGL J1830.2-1005 being the GeV counterpart of HESS J1828-099. Within the RXTE confidence region, a steep-spectrum (α radio = -0.746 ± 0.284) plausible counterpart is detected in data from existing radio frequency surveys. In this Letter, we probe for the first time, using multiwavelength data, whether HESS J1828-099, 4FGL J1830.2-1005, and the HMXB system have a common origin. Our study indicates that HESS J1828-099 might be a TeV high-mass γ-ray binary source.

Keywords: High energy astrophysics, Galactic radio sources, Gamma-ray sources, Massive stars, High mass x-ray binary stars
Tidal Dissipation Due to Inertial Waves Can Explain the Circularization Periods of Solar-type Binaries. Tidal dissipation is responsible for circularizing the orbits and synchronizing the spins of solar-type close binary stars, but the mechanisms responsible are not fully understood. Previous work has indicated that significant enhancements to the theoretically predicted tidal dissipation rates are required to explain the observed circularization periods (P circ) in various stellar populations and their evolution with age. This was based partly on the common belief that the dominant mechanism of tidal dissipation in solar-type stars is turbulent viscosity acting on equilibrium tides in convective envelopes. In this paper, we study tidal dissipation in both convection and radiation zones of rotating solar-type stars following their evolution. We study equilibrium tide dissipation, incorporating a frequency-dependent effective viscosity motivated by the latest hydrodynamical simulations, and inertial wave (dynamical tide) dissipation, adopting a frequency-averaged formalism that accounts for the realistic structure of the star. We demonstrate that the observed binary circularization periods can be explained by inertial wave (dynamical tide) dissipation in convective envelopes. This mechanism is particularly efficient during pre-main-sequence phases, but it also operates on the main sequence if the spin is close to synchronism. The predicted P circ due to this mechanism increases with the main-sequence age in accordance with observations. We also demonstrate that both equilibrium tide and internal gravity-wave dissipation are unlikely to explain the observed P circ, even during the pre-main sequence, based on our best current understanding of these mechanisms. Finally, we advocate more realistic dynamical studies of stellar populations that employ tidal dissipation due to inertial waves.

Keywords: Stellar convective zones, Hydrodynamics, Close binary stars, Exoplanet tides, Planet hosting stars, Tidal interaction, Stellar rotation, Astrophysical fluid dynamics
The High Latitude Spectroscopic Survey on the Nancy Grace Roman Space Telescope. The Nancy Grace Roman Space Telescope will conduct a High Latitude Spectroscopic Survey (HLSS) over a large volume at high redshift, using the near-IR grism (1.0-1.93 μm, R = 435-865) and the 0.28 deg2 wide-field camera. We present a reference HLSS that maps 2000 deg2 and achieves an emission-line flux limit of 10-16 erg s-1 cm-2 at 6.5σ, requiring ~0.6 yr of observing time. We summarize the flowdown of the Roman science objectives to the science and technical requirements of the HLSS. We construct a mock redshift survey over the full HLSS volume by applying a semianalytic galaxy formation model to a cosmological N-body simulation and use this mock survey to create pixel-level simulations of 4 deg2 of HLSS grism spectroscopy. We find that the reference HLSS would measure ~10 million Hα galaxy redshifts that densely map large-scale structure at z = 1-2 and 2 million [O III] galaxy redshifts that sparsely map structures at z = 2-3. We forecast the performance of this survey for measurements of the cosmic expansion history with baryon acoustic oscillations and the growth of large-scale structure with redshift-space distortions. We also study possible deviations from the reference design and find that a deep HLSS at f line &gt; 7 × 10-17 erg s-1 cm-2 over 4000 deg2 (requiring ~1.5 yr of observing time) provides the most compelling stand-alone constraints on dark energy from Roman alone. This provides a useful reference for future optimizations. The reference survey, simulated data sets, and forecasts presented here will inform community decisions on the final scope and design of the Roman HLSS.

Keywords: Cosmology, Dark energy
A New Planet Candidate Detected in a Dust Gap of the Disk around HD 163296 through Localized Kinematic Signatures: An Observational Validation of the DISCMINER. We report the robust detection of coherent, localized deviations from Keplerian rotation possibly associated with the presence of two giant planets embedded in the disk around HD 163296. The analysis is performed using the DISCMINER channel map modeling framework on 12CO J = 2-1 DSHARP data. Not only orbital radius but also azimuth of the planets are retrieved by our technique. One of the candidate planets, detected at R = 94 ± 6 au, ϕ = 50° ± 3° (P94), is near the center of one of the gaps in dust continuum emission and is consistent with a planet mass of 1 M Jup. The other planet, located at R = 261 ± 4 au, ϕ = 57° ± 1° (P261), is in the region where a velocity kink was previously observed in 12CO channel maps. Also, we provide a simultaneous description of the height and temperature of the upper and lower emitting surfaces of the disk and propose the line width as a solid observable to track gas substructure. Using azimuthally averaged line width profiles, we detect gas gaps at R = 38, 88, and 136 au, closely matching the location of their dust and kinematical counterparts. Furthermore, we observe strong azimuthal asymmetries in line widths around the gas gap at R = 88 au, possibly linked to turbulent motions driven by the P94 planet. Our results confirm that the DISCMINER is capable of finding localized, otherwise unseen velocity perturbations thanks to its robust statistical framework, but also that it is well suited for studies of the gas properties and vertical structure of protoplanetary disks.

Keywords: Exoplanet detection methods, Planetary-disk interactions, Protoplanetary disks
New Approach for Analyzing Dynamical Processes on the Surface of Photospheric Vortex Tubes. The majority of studies on multi-scale vortex motions employ a two-dimensional geometry by using a variety of observational and numerical data. This approach limits the understanding the nature of physical processes responsible for vortex dynamics. Here, we develop a new methodology to extract essential information from the boundary surface of vortex tubes. 3D high-resolution magneto-convection MURaM numerical data has been used to analyze photospheric intergranular velocity vortices. The Lagrangian averaged vorticity deviation technique was applied to define the centers of vortex structures and their boundary surfaces based on the advection of fluid elements. These surfaces were mapped onto a constructed envelope grid that allows the study of the key plasma parameters as functions of space and time. Quantities that help in understanding the dynamics of the plasma, e.g., Lorentz force, pressure force, and plasma-β were also determined. Our results suggest that, while density and pressure have a rather global behavior, the other physical quantities undergo local changes, with their magnitude and orientation changing in space and time. At the surface, the mixing in the horizontal direction is not efficient, leading to appearance of localized regions with higher/colder temperatures. In addition, the analysis of the MHD Poynting flux confirms that the majority of the energy is directed in the horizontal direction. Our findings also indicate that the pressure and magnetic forces that drive the dynamics of the plasma on vortex surfaces are unbalanced and therefore the vortices do not rotate as a rigid body.

Keywords: Solar atmospheric motions, Solar granulation, Solar photosphere, Magnetohydrodynamical simulations
Model-independent Reconstruction of the Cosmological Scale Factor as a Function of Lookback Time. We present a model-independent method of reconstructing scale factor against lookback time from the Observational Hubble parameter Data (OHD). The reconstruction method is independent of dynamical models and is only based on the Friedmann-Robertson-Walker metric. We also calculate the propagation of error in the reconstruction process. The reconstruction data errors mainly come from trapezoidal rule approximation and the uncertainty from OHD. Furthermore, the model discrimination ability of original OHD and reconstructed a-t data is discussed under a dimensionless standard method. The a-t data can present the differences between cosmology models more clearly than H-z data by comparing their coefficients of variations. Finally, we add 50 simulated H(z) data to estimate the influence of future observation. More Hubble measurements in the future will help constrain cosmological parameters more accurately.

Keywords: Cosmological models, Stellar distance, Astronomy data analysis, Cosmological parameters