Sazuna/UAT_keywords huggingface dataset:
Diverse Carbonates in Exoplanet Oceans Promote the Carbon Cycle. Carbonate precipitation in oceans is essential for the carbonate-silicate cycle (inorganic carbon cycle) to maintain temperate climates. By considering the thermodynamics of carbonate chemistry, we demonstrate that the ocean pH decreases by approximately 0.5 for a factor of 10 increase in the atmospheric carbon dioxide content. The upper and lower limits of ocean pH are within 1-4 of each other, where the upper limit is buffered by carbonate precipitation and defines the ocean pH when the carbon cycle operates. If the carbonate compensation depth (CCD) resides above the ocean floor, then carbonate precipitation and the carbon cycle cease to operate. The CCD is deep (&gt;40 km) for high ocean temperature and high atmospheric carbon dioxide content. Key divalent carbonates of magnesium, calcium and iron produce an increasingly wider parameter space of deep CCDs, suggesting that chemical diversity promotes the carbon cycle. The search for life from exoplanets will benefit by including chemically more diverse targets than Earth twins.

Keywords: Extrasolar rocky planets, Ocean-atmosphere interactions, Carbon dioxide, Planetary geology, Habitable zone
Possible Evidence for Lorentz Invariance Violation in Gamma-Ray Burst 221009A. The preliminary detections of the gamma-ray burst 221009A up to 18 TeV by LHAASO and up to 251 TeV by Carpet 2 have been reported through Astronomer's Telegrams and Gamma-ray Coordination Network circulars. Since this burst is at redshift z = 0.1505, these photons may at first seem to have a low probability to avoid pair production off of background radiation fields and survive to reach detectors on Earth. By extrapolating the reported 0.1-1.0 GeV Fermi Large Area Telescope spectrum from this burst to higher energies and using this to limit the intrinsic spectrum of the burst, we show that the survival of the 18 TeV photon detected by LHAASO is not unlikely with many recent extragalactic background light models, although the detection of a 251 TeV event is still very unlikely. This can be resolved if Lorentz invariance is violated at an energy scale E QG ≲ 49E Planck in the linear (n = 1) case, and E QG ≲ 10-6 E Planck in the quadratic (n = 2) case (95% confidence limits), where E Planck is the Planck energy. This could potentially be the first evidence for subluminal Lorentz invariance violation.

Keywords: Gamma-ray astronomy, Gamma-ray bursts, Quantum gravity
Macrospicules and Their Connection to Magnetic Reconnection in the Lower Solar Atmosphere. Solar macrospicules are beam-like cool plasma ejections of size in between spicules and coronal jets, which can elucidate potential connections between plasma jetting activity at different scales. With high-resolution observations from the New Vacuum Solar Telescope and Solar Dynamics Observatory, we investigate the origin of five groups of recurrent active-region macrospicules. Before the launch of each macrospicule, we detect a compact bright patch (BP) at its base where a newly emerging dipole contacts and cancel with the preexisting ambient field. The spectral diagnosis from the Interface Region Imaging Spectrograph at one of BPs reveals signatures of reconnection at the lower atmosphere. Multiwavelength imaging of these BPs show that they mainly occur at the rising phase of the flux emergence and slowly ascend from the lower to the upper chromosphere. Remarkable macrospicules occur and fade out once the BPs appear and decay from the AIA 304 Å images, respectively. We suggest that these macrospicules and related BPs form in a common reconnection process, in which the increasing reconnection height between the emerging dipole and the ambient field results in the observed variations from BPs to macrospicules. Interestingly, most macrospicules show similar characteristics to larger-scale coronal jets and/or smaller-scale spicules, i.e., the rotating motions, the presence of minifilaments and BPs before the eruptions, and magnetic flux emergence and cancellation. We conclude that the formation mechanism of macrospicules should be the same as spicules and coronal jets, i.e., solar jetting phenomena at different scales share the same physical mechanism in association with magnetic reconnection.

Keywords: Solar activity, Solar chromosphere, Solar magnetic reconnection, Solar spicules
DDO68 C: The Actual Appearance of a Ghost Satellite Dwarf through Adaptive Optics at the Large Binocular Telescope. Through adaptive optics (AO) imaging with the SOUL+LUCI instrument at the Large Binocular Telescope we were able to resolve, for the first time, individual stars in the gas-rich galaxy DDO68 C. This system was already suggested to be interacting with the extremely metal-poor dwarf DDO68, but its nature has remained elusive so far because of the presence of a bright foreground star close to its line of sight that hampers a detailed study of its stellar population and distance. In our study, we turned this interloper star into an opportunity to have a deeper insight on DDO68 C, using it as a guide star for the AO correction. Although the new data do not allow for a direct distance measurement through the red giant branch tip method, the combined analysis of the resolved-star color-magnitude diagram, of archival GALEX far-UV and near-UV photometry, and of Hα data provides a self-consistent picture in which DDO68 C is at the same ~13 Mpc distance as its candidate companion DDO68. These results indicate that DDO68 is a unique case of a low-mass dwarf, less massive than the Magellanic Clouds, interacting with three satellites (DDO68 C and two previously confirmed accreting systems), providing useful constraints on cosmological models and a potential explanation for its anomalous extremely low metallicity.

Keywords: Dwarf irregular galaxies, Dwarf galaxies, Galaxy stellar content, Adaptive optics, Interacting galaxies
UGC 4211: A Confirmed Dual Active Galactic Nucleus in the Local Universe at 230 pc Nuclear Separation. We present multiwavelength high-spatial resolution (~0.″1, 70 pc) observations of UGC 4211 at z = 0.03474, a late-stage major galaxy merger at the closest nuclear separation yet found in near-IR imaging (0.″32, ~230 pc projected separation). Using Hubble Space Telescope/Space Telescope Imaging Spectrograph, Very Large Telescope/MUSE+AO, Keck/OSIRIS+AO spectroscopy, and the Atacama Large Millimeter/submillimeter Array (ALMA) observations, we show that the spatial distribution, optical and near-infrared emission lines, and millimeter continuum emission are all consistent with both nuclei being powered by accreting supermassive black holes (SMBHs). Our data, combined with common black hole mass prescriptions, suggest that both SMBHs have similar masses, $\mathrm{log}\left({M}_{\mathrm{BH}}/{M}_{\odot }\right)$ ~ 8.1 (south) and $\mathrm{log}\left({M}_{\mathrm{BH}}/{M}_{\odot }\right)$ ~ 8.3 (north), respectively. The projected separation of 230 pc (~6× the black hole sphere of influence) represents the closest-separation dual active galactic nuclei (AGN) studied to date with multiwavelength resolved spectroscopy and shows the potential of nuclear (&lt;50 pc) continuum observations with ALMA to discover hidden growing SMBH pairs. While the exact occurrence rate of close-separation dual AGN is not yet known, it may be surprisingly high, given that UGC 4211 was found within a small, volume-limited sample of nearby hard X-ray detected AGN. Observations of dual SMBH binaries in the subkiloparsec regime at the final stages of dynamical friction provide important constraints for future gravitational wave observatories.

Keywords: AGN host galaxies, AB photometry, Galaxy collisions, X-ray active galactic nuclei, Galaxy mergers, Interacting galaxies
Early Results from GLASS-JWST. IX. First Spectroscopic Confirmation of Low-mass Quiescent Galaxies at z &gt; 2 with NIRISS. How passive galaxies form, and the physical mechanisms which prevent star formation over long timescales, are some of the most outstanding questions in understanding galaxy evolution. The properties of quiescent galaxies over cosmic time provide crucial information to identify the quenching mechanisms. Passive galaxies have been confirmed and studied out to z ~ 4, but all of these studies have been limited to massive systems (mostly with $\mathrm{log}({M}_{\mathrm{star}}/{M}_{\odot })\gt 10.8$ ). Using JWST-NIRISS grism slitless spectroscopic data from the GLASS-JWST Early Release Science program, we present spectroscopic confirmation of two quiescent galaxies at ${z}_{\mathrm{spec}}={2.650}_{-0.006}^{+0.004}$ and ${z}_{\mathrm{spec}}={2.433}_{-0.016}^{+0.032}$ (3σ errors) with stellar masses of $\mathrm{log}({M}_{\mathrm{star}}/{M}_{\odot })={10.59}_{-0.05}^{+0.11}$ and $\mathrm{log}({M}_{\mathrm{star}}/{M}_{\odot })={10.07}_{-0.03}^{+0.06}$ (corrected for magnification factors of μ = 2.0 and μ = 2.1, respectively). The latter represents the first spectroscopic confirmation of the existence of low-mass quiescent galaxies at cosmic noon, showcasing the power of JWST to identify and characterize this enigmatic population.

Keywords: High-redshift galaxies, Quenched galaxies, Galaxies
Early Results from GLASS-JWST. X. Rest-frame UV-optical Properties of Galaxies at 7 &lt; z &lt; 9. We present the first James Webb Space Telescope/NIRCam-led determination of 7 &lt; z &lt; 9 galaxy properties based on broadband imaging from 0.8 to 5 μm as part of the GLASS-JWST Early Release Science program. This is the deepest data set acquired at these wavelengths to date, with an angular resolution ≲0.″14. We robustly identify 13 galaxies with signal-to-noise ratio ≳ 8 in F444W from 8 arcmin2 of data at m AB ≤ 28 from a combination of dropout and photometric redshift selection. From simulated data modeling, we estimate the dropout sample purity to be ≳90%. We find that the number density of these F444W-selected sources is broadly consistent with expectations from the UV luminosity function determined from Hubble Space Telescope data. We characterize galaxy physical properties using a Bayesian spectral energy distribution fitting method, finding a median stellar mass of 108.5 M ⊙ and age 140 Myr, indicating they started ionizing their surroundings at redshift z &gt; 9.5. Their star formation main sequence is consistent with predictions from simulations. Lastly, we introduce an analytical framework to constrain main-sequence evolution at z &gt; 7 based on galaxy ages and basic assumptions, through which we find results consistent with expectations from cosmological simulations. While this work only gives a glimpse of the properties of typical galaxies that are thought to drive the reionization of the universe, it clearly shows the potential of JWST to unveil unprecedented details of galaxy formation in the first billion years.

Keywords: High-redshift galaxies, Galaxy evolution
Early Results from GLASS-JWST. XI. Stellar Masses and Mass-to-light Ratio of z &gt; 7 Galaxies. We exploit James Webb Space Telescope (JWST) NIRCam observations from the GLASS-JWST-Early Release Science program to investigate galaxy stellar masses at z &gt; 7. We first show that JWST observations reduce the uncertainties on the stellar mass by a factor of at least 5-10, when compared with the highest-quality data sets available to date. We then study the UV mass-to-light ratio, finding that galaxies exhibit a a two orders of magnitude range of M/L UV values for a given luminosity, indicative of a broad variety of physical conditions and star formation histories. As a consequence, previous estimates of the cosmic stellar-mass density-based on an average correlation between UV luminosity and stellar mass-can be biased by as much as a factor of ~6. Our first exploration demonstrates that JWST represents a new era in our understanding of stellar masses at z &gt; 7 and, therefore, of the growth of galaxies prior to cosmic reionization.

Keywords: Mass-to-light ratio, High-redshift galaxies, Stellar masses
Early Results From GLASS-JWST. XII. The Morphology of Galaxies at the Epoch of Reionization. Star-forming galaxies can exhibit strong morphological differences between the rest-frame far-UV and optical, reflecting inhomogeneities in star formation and dust attenuation. We exploit deep, high-resolution, NIRCAM seven-band observations to take a first look at the morphology of galaxies in the epoch of reionization (z &gt; 7), and its variation in the rest-frame wavelength range between Lyα and 6000-4000 Å, at z = 7-12. We find no dramatic variations in morphology with wavelength-of the kind that would have overturned anything we have learned from the Hubble Space Telescope. No significant trends between morphology and wavelengths are detected using standard quantitative morphology statistics. We detect signatures of mergers/interactions in 4/19 galaxies. Our results are consistent with a scenario in which Lyman-break galaxies-observed when the universe is only 400-800 Myr old-are growing via a combination of rapid, galaxy-scale star formation supplemented by the accretion of star-forming clumps and interactions.

Keywords: High-redshift galaxies
Early Results from GLASS-JWST. XIII. A Faint, Distant, and Cold Brown Dwarf. We present the serendipitous discovery of a late T-type brown dwarf candidate in JWST NIRCam observations of the Early Release Science Abell 2744 parallel field. The discovery was enabled by the sensitivity of JWST at 4 μm wavelengths and the panchromatic 0.9-4.5 μm coverage of the spectral energy distribution. The unresolved point source has magnitudes F115W = 27.95 ± 0.15 and F444W = 25.84 ± 0.01 (AB), and its F115W-F444W and F356W-F444W colors match those expected for other known T dwarfs. We can exclude it as a reddened background star, high redshift quasar, or a very high redshift galaxy. Comparison with stellar atmospheric models indicates a temperature of T eff ≈ 650 K and surface gravity $\mathrm{log}g\approx 5.25$ , implying a mass of 0.03 M ⊙ and age of 5 Gyr. We estimate the distance of this candidate to be 570-720 pc in a direction perpendicular to the Galactic plane, making it a likely thick disk or halo brown dwarf. These observations underscore the power of JWST to probe the very low-mass end of the substellar mass function in the Galactic thick disk and halo. *Based on data collected with JWST.

Keywords: T dwarfs
Deciphering the  18 TeV Photons from GRB 221009A. On 2022 October 9, an extremely powerful gamma-ray burst, GRB 221009A, was detected by several instruments. Despite being obstructed by the Milky Way galaxy, its afterglow outburst outshone all other GRBs seen before. LHAASO detected several thousand very high energy photons extending up to 18 TeV. Detection of such energetic photons is unexpected due to the large opacity of the universe. It is possible that in the afterglow epoch, the intrinsic very high energy photon flux from the source might have increased manifolds, which could compensate for the attenuation by pair production with the extragalactic background light. We propose such a scenario and show that very high energy photons can be observed on the Earth from the interaction of very high energy protons with the seed synchrotron photons in the external forward shock region of the GRB jet.

Keywords: Gamma-ray bursts, Particle astrophysics
Prospects for the Observation of Continuous Gravitational Waves from Spinning Neutron Stars Lensed by the Galactic Supermassive Black Hole. We study the prospects of detecting continuous gravitational waves (CGWs) from spinning neutron stars (NSs), gravitationally lensed by the galactic supermassive black hole. Assuming various astrophysically motivated spatial distributions of galactic NSs, we find that CGW signals from a few (~0-6) neutron stars should be strongly lensed. Lensing will produce two copies of the signal (with time delays of seconds to minutes) that will interfere with each other. The relative motion of the NS with respect to the lensing optical axis will change the interference pattern, which will help us to identify a lensed signal. Accounting for the magnifications and time delays of the lensed signals, we investigate their detectability by ground-based detectors. Modeling the spin distribution of NSs based on that of known pulsars and assuming an ellipticity of ϵ = 10-7, lensed CGWs are unlikely to be detectable by LIGO and Virgo in realistic searches involving ${ \mathcal O }({10}^{12})$ templates. However, third-generation detectors have a ~2%-51% probability of detecting at least one lensed CGW signal. For an ellipticity of ϵ = 10-8, the detection probability reduces to ~0%-18%. Though rare, such an observation will enable interesting probes of the supermassive black hole and its environment.

Keywords: Neutron stars, Strong gravitational lensing, Gravitational wave sources, Gravitational wave astronomy, General relativity, Gravitational waves
Rejuvenated Accretors Have Less Bound Envelopes: Impact of Roche Lobe Overflow on Subsequent Common Envelope Events. Common envelope (CE) evolution is an outstanding open problem in stellar evolution, critical to the formation of compact binaries including gravitational-wave sources. In the "classical" isolated binary evolution scenario for double compact objects, the CE is usually the second mass transfer phase. Thus, the donor star of the CE is the product of a previous binary interaction, often stable Roche lobe overflow (RLOF). Because of the accretion of mass during the first RLOF, the main-sequence core of the accretor star grows and is "rejuvenated." This modifies the core-envelope boundary region and decreases significantly the envelope binding energy for the remaining evolution. Comparing accretor stars from self-consistent binary models to stars evolved as single, we demonstrate that the rejuvenation can lower the energy required to eject a CE by ~42%-96% for both black hole and neutron star progenitors, depending on the evolutionary stage and final orbital separation. Therefore, binaries experiencing first stable mass transfer may more easily survive subsequent CE events and result in possibly wider final separations compared to current predictions. Despite their high mass, our accretors also experience extended "blue loops," which may have observational consequences for low-metallicity stellar populations and asteroseismology.

Keywords: Roche lobe overflow, Binary stars, Common envelope binary stars
Live to Die Another Day: The Rebrightening of AT 2018fyk as a Repeating Partial Tidal Disruption Event. Stars that interact with supermassive black holes (SMBHs) can be either completely or partially destroyed by tides. In a partial tidal disruption event (TDE), the high-density core of the star remains intact, and the low-density outer envelope of the star is stripped and feeds a luminous accretion episode. The TDE AT 2018fyk, with an inferred black hole mass of 107.7±0.4 M ☉, experienced an extreme dimming event at X-ray (factor of &gt;6000) and UV (factor of ~15) wavelengths ~500-600 days after discovery. Here we report on the reemergence of these emission components roughly 1200 days after discovery. We find that the source properties are similar to those of the predimming accretion state, suggesting that the accretion flow was rejuvenated to a similar state. We propose that a repeated partial TDE, where the partially disrupted star is on an ~1200 day orbit about the SMBH and periodically stripped of mass during each pericenter passage, powers its unique light curve. This scenario provides a plausible explanation for AT 2018fyk's overall properties, including the rapid dimming event and the rebrightening at late times. We also provide testable predictions for the behavior of the accretion flow in the future; if the second encounter was also a partial disruption, then we predict another strong dimming event around day 1800 (2023 August) and a subsequent rebrightening around day 2400 (2025 March). This source provides strong evidence of the partial disruption of a star by an SMBH.

Keywords: Accretion, Tidal disruption, Stellar dynamics, X-ray transient sources, Ultraviolet transient sources
As a Matter of Dynamical Range - Scale Dependent Energy Dynamics in MHD Turbulence. Magnetized turbulence is ubiquitous in many astrophysical and terrestrial plasmas but no universal theory exists. Even the detailed energy dynamics in magnetohydrodynamic (MHD) turbulence are still not well understood. We present a suite of subsonic, super-Alfvénic, high plasma beta MHD turbulence simulations that only vary in their dynamical range, i.e., in their separation between the large-scale forcing and dissipation scales, and their dissipation mechanism (implicit large eddy simulation, ILES, and direct numerical simulation (DNS)). Using an energy transfer analysis framework we calculate the effective numerical viscosities and resistivities, and demonstrate that all ILES calculations of MHD turbulence are resolved and correspond to an equivalent visco-resistive MHD turbulence calculation. Increasing the number of grid points used in an ILES corresponds to lowering the dissipation coefficients, i.e., larger (kinetic and magnetic) Reynolds numbers for a constant forcing scale. Independently, we use this same framework to demonstrate that-contrary to hydrodynamic turbulence-the cross-scale energy fluxes are not constant in MHD turbulence. This applies both to different mediators (such as cascade processes or magnetic tension) for a given dynamical range as well as to a dependence on the dynamical range itself, which determines the physical properties of the flow. We do not observe any indication of convergence even at the highest resolution (largest Reynolds numbers) simulation at 20483 cells, calling into question whether an asymptotic regime in MHD turbulence exists, and, if so, what it looks like.

Keywords: Magnetohydrodynamics, Theoretical techniques, Plasma astrophysics, Computational methods, Magnetic fields, Magnetohydrodynamical simulations
Missing for 20 yr: MeerKAT Redetects the Elusive Binary Pulsar M30B. PSR J2140-2311B is a 13 ms pulsar discovered in 2001 in a 7.8 hr Green Bank Telescope observation of the core-collapsed globular cluster M30 and predicted to be in a highly eccentric binary orbit. This pulsar has eluded detection since then; therefore, its precise orbital parameters have remained a mystery until now. In this work, we present the confirmation of this pulsar using observations taken with the UHF receivers of the MeerKAT telescope as part of the TRAPUM Large Survey Project. Taking advantage of the beamforming capability of our backends, we have localized it, placing it 1.'2(1) from the cluster center. Our observations have enabled the determination of its orbit: It is highly eccentric (e = 0.879) with an orbital period of 6.2 days. We also measured the rate of periastron advance, $\dot{\omega }=0.078\pm 0.002\,\deg \,{\mathrm{yr}}^{-1}$ . Assuming that this effect is fully relativistic, general relativity provides an estimate of the total mass of the system, M TOT = 2.53 ± 0.08 M ⊙, consistent with the lightest double neutron star systems known. Combining this with the mass function of the system gives the pulsar and companion masses of m  p  &lt; 1.43 M ⊙ and m  c  &gt; 1.10 M ⊙, respectively. The massive, undetected companion could either be a massive white dwarf or a neutron star. M30B likely formed as a result of a secondary exchange encounter. Future timing observations will allow the determination of a phase-coherent timing solution, vastly improving our uncertainty in $\dot{\omega }$ and likely enabling the detection of additional relativistic effects, which will determine m  p  and m  c .

Keywords: Globular star clusters, Radio pulsars