Sazuna/UAT_keywords huggingface dataset:
Gravitational Wave Sources in Our Galactic Backyard: Predictions for BHBH, BHNS, and NSNS Binaries Detectable with LISA. Future searches for gravitational waves from space will be sensitive to double compact objects in our Milky Way. We present new simulations of the populations of double black holes (BHBHs), BH neutron stars (BHNSs), and double neutron stars (NSNSs) that will be detectable by the planned space-based gravitational-wave detector called Laser Interferometer Space Antenna (LISA). For our estimates, we use an empirically informed model of the metallicity-dependent star formation history of the Milky Way. We populate it using an extensive suite of binary population-synthesis predictions for varying assumptions relating to mass transfer, common-envelope, supernova kicks, remnant masses, and wind mass-loss physics. For a 4(10) yr LISA mission, we predict between 30-370(50-550) detections over these variations, out of which 6-154 (9-238) are BHBHs, 2-198 (3-289) are BHNSs, and 3-35 (4-57) are NSNSs. We expect that about 50% (60%) can be distinguished from double white dwarf sources based on their mass or eccentricity and localization. Specifically, for about 10% (15%), we expect to be able to determine chirp masses better than 10%. For 13% (13%), we expect sky-localizations better than 1°. We discuss how the variations in the physics assumptions alter the distribution of properties of the detectable systems, even when the detection rates are unchanged. We further discuss the possibility of multimessenger observations of pulsar populations with the Square Kilometre Array and assess the benefits of extending the LISA mission.

Keywords: Neutron stars, Gravitational wave detectors, Binary stars, Stellar mass black holes, Pulsars, Gravitational waves, Compact objects, Stellar evolution
Orbital Dynamics Landscape near the Most Distant Known Trans-Neptunian Objects. The most distant known trans-Neptunian objects (TNOs), those with perihelion distance above 38 au and semimajor axis above 150 au, are of interest for their potential to reveal past, external, or present but unseen perturbers. Realizing this potential requires understanding how the known planets influence their orbital dynamics. We use a recently developed Poincaré mapping approach for orbital phase space studies of the circular planar restricted three-body problem, which we have extended to the case of the 3D restricted problem with N planetary perturbers. With this approach, we explore the dynamical landscape of the 23 most distant TNOs under the perturbations of the known giant planets. We find that, counter to common expectations, almost none of these TNOs are far removed from Neptune's resonances. Nearly half (11) of these TNOs have orbits consistent with stable libration in Neptune's resonances; in particular, the orbits of TNOs 148209 and 474640 overlap with Neptune's 20:1 and 36:1 resonances, respectively. Five objects can be ruled currently nonresonant, despite their large orbital uncertainties, because our mapping approach determines the resonance boundaries in angular phase space in addition to semimajor axis. Only three objects are in orbital regions not appreciably affected by resonances: Sedna, 2012 VP113 and 2015 KG163. Our analysis also demonstrates that Neptune's resonances impart a modest (few percent) nonuniformity in the longitude of perihelion distribution of the currently observable distant TNOs. While not large enough to explain the observed clustering, this small dynamical sculpting of the perihelion longitudes could become relevant for future, larger TNO data sets.

Keywords: Kuiper belt, Resonant Kuiper belt objects, Orbital resonances, Celestial mechanics, Detached objects, Trans-Neptunian objects
CN 2-1 and CS 5-4 Observations toward Arp 299 with the SMA. Dense gas is the key to understanding star formation in galaxies. We present high-resolution (~3″) observations of CN 2-1 and CS 5-4 as dense gas tracers toward Arp 299, a mid-stage major merger of galaxies, with the Submillimeter Array. The spatial distribution of CN 2-1 and CS 5-4 are generally consistent with each other, as well as HCN 1-0 in the literature. However, different line ratios of CS 5-4 and CN 2-1 are found in the A, B, and C regions, with the highest value in B. Dense gas fraction decreases from IC 694 (A) to NGC 3690 (B) and the starburst in the overlap regions (C and C'), which indicates that circumnuclear upcoming starburst in A and B will be more efficient than that in the overlap region of Arp 299.

Keywords: Galaxy mergers
The 3D X-Ray Ejecta Structure of Tycho's Supernova Remnant. We present our velocity measurements of 59 clumpy, metal-rich ejecta knots in the supernova remnant (SNR) of SN 1572 (Tycho). We use our 450 ks Chandra High Energy Transmission Grating Spectrometer observation to measure the Doppler shift of the He-like Si Kα line-center wavelength emitted from these knots to find their line-of-sight (radial) velocities (v  r ). We find v  r  up to ~5500 km s-1, with roughly consistent speeds between blueshifted and redshifted ejecta knots. We also measure the proper motions (PMs) for our sample based on archival Chandra Advanced CCD Imaging Spectrometer data taken from 2003, 2009, and 2015. We estimate PMs up to 0.″35 yr-1, which corresponds to a transverse velocity of about 5800 km s-1 for the distance of 3.5 kpc to Tycho. Our v  r  and transverse velocity measurements imply space velocities of ~1900-6000 km s-1 for the ejecta knots in Tycho. We estimate a new expansion center of R.A.(J2000) = 00h25m18s.725 ± 1.ˢ157 and decl.(J2000) = +64°08'02.″5 ± 11.″2 from our PM measurements, consistent to within ~13″ of the geometric center. The distribution of space velocities throughout the remnant suggests that the southeast quadrant generally expands faster than the rest of the SNR. We find that blueshifted knots are projected more in the northern shell, while redshifted knots are more in the southern shell. The previously estimated reverse shock position is consistent with most of our estimated ejecta distribution; however, some ejecta show deviations from the 1D picture of the reverse shock.

Keywords: X-ray astronomy, Interstellar dynamics, Supernova remnants, Type Ia supernovae, Proper motions, Radial velocity
The Expansion of the X-Ray Nebula Around η Car. The massive colliding wind binary system η Car is embedded in an X-ray emitting region having a characteristic temperature of a few million degrees, associated with ejecta produced during the 1840s, and in earlier outbursts. We use CHANDRA X-ray imaging observations obtained over the past two decades to directly measure the expansion of the X-ray nebula for the first time. A combined CHANDRA/ACIS image shows a faint, nearly uniform elliptic structure. This faint elliptical "shell" has a similar orientation and shape as the Homunculus nebula but is about 3 times larger. We measure proper motions of brighter regions associated with the X-ray emitting ring. We compare spectra of the soft X-ray emitting plasma in CHANDRA/ACIS and XMM-Newton PN observations and show that the PN observations indicate a decline in X-ray flux which is comparable to that derived from NICER observations. We associate the diffuse elliptical emission surrounding the bright X-ray "ring" with the blast wave produced during the Great Eruption. We suggest that the interaction of this blast wave with pre-existing clumps of ejecta produces the bright, broken X-ray emitting ring. We extrapolate the trend in X-ray energy back to the time of the Great Eruption using a simple model and show that the X-ray energy was comparable to the kinetic energy of the Homunculus, suggesting equipartition of energy between fast, low-density ejecta and slower, dense ejecta.

Keywords: Circumstellar shells, Proper motions, High energy astrophysics
Origin of Nitrogen Isotopic Variations in the Rocky Bodies of the Solar System. Noncarbonaceous (NC; inner solar system) meteorites have lower 15N/14N ratios than carbonaceous (CC; outer solar system) meteorites. Whether this is evidence of a primordial heterogeneity of N reservoirs in the protosolar disk remains unclear. In this study, I consider the N isotopic compositions of meteorite (chondrite, achondrite, and iron meteorite) parent bodies as a function of their growth zones. Despite the 15N/14N ratios of CC meteorites being generally higher than NC meteorites, there is a substantial overlap between them. Late-stage mixing of isotopically distinct reservoirs cannot explain this overlap. 15N/14N ratios of meteorites, independent of the growth zones, are correlated with the accretion ages of their parent bodies. A common correlation of the 15N/14N ratios of NC and CC chondrites with their peak metamorphic temperatures suggests that N isotopic compositions of meteorites were likely set by a universal time-dependent process-thermal evolution of their parent bodies by radiogenic heating. Therefore, heterogeneous N isotopic compositions of meteorites do not allude to isotopically heterogeneous primitive N reservoirs in the protosolar disk. Rather, it is likely that the N isotopic compositions of meteorites are a direct reflection of a differential response of labile 15N-rich and refractory 15N-poor components in common organic precursors to variable degrees of parent body processing. Consequently, the isotopic ratios of N, and other highly volatile elements like C and H, in meteorites do not reflect the isotopic compositions of primitive volatile reservoirs in the protosolar disk and thus cannot be used independently to cosmolocate volatile reservoirs in the disk.

Keywords: Chondrites, Iron meteorites, Protoplanetary disks, Planetesimals, Meteorites, Planet formation
Impacts of the Direct Urca and Superfluidity inside a Neutron Star on Type I X-Ray Bursts and X-Ray Superbursts. We investigate the impacts of the neutrino cooling mechanism inside the neutron star (NS) core on the light curves of type I X-ray bursts and X-ray superbursts. From several observations of NS thermal evolution, physical processes of fast neutrino cooling, such as the direct Urca (DU) process, are indicated. They significantly decrease the surface temperature of NSs, though the cooling effect could be suppressed by nucleon superfluidity. In the present study, focusing on the DU process and nucleon superfluidity, we investigate the effects of NS cooling on the X-ray bursts using a general-relativistic stellar-evolution code. We find that the DU process leads to a longer recurrence time and higher peak luminosity, which could be obstructed by the neutrons' superfluidity. We also apply our burst models to the comparison with Clocked burster GS 1826-24, and to the recurrence time of a superburst triggered by carbon ignition. These effects are significant within a certain range of binary parameters and the uncertainty of the NS equation of state.

Keywords: Neutron stars, Low-mass x-ray binary stars, Neutron star cores, X-ray bursts
Orbital Decay in M82 X-2. M82 X-2 is the first pulsating ultraluminous X-ray source discovered. The luminosity of these extreme pulsars, if isotropic, implies an extreme mass transfer rate. An alternative is to assume a much lower mass transfer rate, but with an apparent luminosity boosted by geometrical beaming. Only an independent measurement of the mass transfer rate can help discriminate between these two scenarios. In this paper, we follow the orbit of the neutron star for 7 yr, measure the decay of the orbit ( ${\dot{P}}_{\mathrm{orb}}/{P}_{\mathrm{orb}}\approx -8\cdot {10}^{-6}\,{\mathrm{yr}}^{-1}$ ), and argue that this orbital decay is driven by extreme mass transfer of more than 150 times the mass transfer limit set by the Eddington luminosity. If this is true, the mass available to the accretor is more than enough to justify its luminosity, with no need for beaming. This also strongly favors models where the accretor is a highly magnetized neutron star.

Keywords: Orbital evolution, Ultraluminous x-ray sources, Pulsar timing method, Pulsars
Evidence of the Alfvén Transition Layer and Particle Precipitation in the Cusp Region: 3D Global PIC Simulation of the Solar Wind-Earth Magnetosphere Interaction. A transition layer, named the Alfvénic transition layer (or ATL), has been clearly evidenced near the outer boundary of the cusp by experimental observations from the Cluster mission. This layer characterized by a local value of Log M A ~ 1, where M A is the Alfvén Mach number, allows the bulk flow to transit from super-Alfvénic to sub-Alfvénic from the exterior to the interior side of the outer cusp. The ATL has been observed during northward interplanetary magnetic field orientation, and mainly within the meridian plane. Currently, 3D Particle In Cell (PIC) global simulations of the solar wind-magnetosphere interaction are being performed in order to analyze the cusp region and this layer in detail. Present results stress the following points: (i) the ATL has a 3D structure; (ii) within the meridian plane, the ATL appears as a sublayer within a much more extended slow-mode pattern, and it is almost adjacent and located above the upper edge of the stagnant exterior cusp (SEC); and (iii) the plasma deceleration through the ATL is not uniform in the region located above the cusp. In addition, present preliminary results stress that (a) the spiraled streamlines of ion/electron fluxes converge when approaching the cusp, and their intensity strongly increases; and (b) ion and electron energetic fluxes penetrating the cusp region strongly differ in terms of their penetration depths and are issued from different regions of the magnetosphere/magnetosheath. Our results illustrate the importance of 3D effects used with a PIC simulation approach allowing the analysis of each population simultaneously.

Keywords: Planetary magnetospheres
ALMA Detection of Dust Trapping around Lagrangian Points in the LkCa 15 Disk. We present deep high-resolution (~50 mas, 8 au) Atacama Large Millimeter/submillimeter Array (ALMA) 0.88 and 1.3 mm continuum observations of the LkCa 15 disk. The emission morphology shows an inner cavity and three dust rings at both wavelengths, but with slightly narrower rings at the longer wavelength. Along a faint ring at 42 au, we identify two excess emission features at ~10σ significance at both wavelengths: one as an unresolved clump and the other as an extended arc, separated by roughly 120° in azimuth. The clump is unlikely to be a circumplanetary disk (CPD) as the emission peak shifts between the two wavelengths even after accounting for orbital motion. Instead, the morphology of the 42 au ring strongly resembles the characteristic horseshoe orbit produced in planet-disk interaction models, where the clump and the arc trace dust accumulation around Lagrangian points L 4 and L 5, respectively. The shape of the 42 au ring, dust trapping in the outer adjacent ring, and the coincidence of the horseshoe ring location with a gap in near-IR scattered light, are all consistent with the scenario of planet sculpting, with the planet likely having a mass between those of Neptune and Saturn. We do not detect pointlike emission associated with a CPD around the putative planet location (0.″27 in projected separation from the central star at a position angle of ~60°), with upper limits of 70 and 33 μJy at 0.88 and 1.3 mm, respectively, corresponding to dust mass upper limits of 0.02-0.03 M ⊕.

Keywords: Exoplanet formation, Planetary-disk interactions, Protoplanetary disks
Migratory Outbursting Quasi-Hilda Object 282P/(323137) 2003 BM80. We report that object 282P/(323137) 2003 BM80 is undergoing a sustained activity outburst, lasting over 15 months thus far. These findings stem in part from our NASA Partner Citizen Science project Active Asteroids (http://activeasteroids.net), which we introduce here. We acquired new observations of 282P via our observing campaign (Vatican Advanced Technology Telescope (VATT), Lowell Discovery Telescope (LDT), and the Gemini South telescope), confirming 282P was active on UT 2022 June 7, some 15 months after 2021 March images showed activity in the 2021-2022 epoch. We classify 282P as a member of the quasi-Hilda objects (QHOs), a group of dynamically unstable objects found in an orbital region similar to, but distinct in their dynamical characteristics to, the Hilda asteroids (objects in 3:2 resonance with Jupiter). Our dynamical simulations show 282P has undergone at least five close encounters with Jupiter and one with Saturn over the last 180 yr. 282P was most likely a Centaur or Jupiter-family comet (JFC) 250 yr ago. In 350 yr, following some 15 strong Jovian interactions, 282P will most likely migrate to become a JFC or, less likely, an outer main-belt asteroid orbit. These migrations highlight a dynamical pathway connecting Centaurs and JFCs with quasi-Hildas and, potentially, active asteroids. Synthesizing these results with our thermodynamical modeling and new activity observations, we find volatile sublimation is the primary activity mechanism. Observations of a quiescent 282P, which we anticipate will be possible in 2023, will help confirm our hypothesis by measuring a rotation period and ascertaining the spectral type. * Based on observations obtained at the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation on behalf of the Gemini Observatory partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). ** Magellan telescope time was granted by NSF's NOIRLab, through the Telescope System Instrumentation Program (TSIP). TSIP was funded by the National Science Foundation (NSF).

Keywords: Centaur group, Asteroid dynamics, Comet tails, Comet dynamics, Hilda group
Ultrafaint Dwarf Galaxy Candidates in the M81 Group: Signatures of Group Accretion. The faint and ultrafaint dwarf galaxies in the Local Group form the observational bedrock upon which our understanding of small-scale cosmology rests. In order to understand whether this insight generalizes, it is imperative to use resolved-star techniques to discover similarly faint satellites in nearby galaxy groups. We describe our search for ultrafaint galaxies in the M81 group using deep ground-based resolved-star data sets from Subaru's Hyper Suprime-Cam. We present one new ultrafaint dwarf galaxy in the M81 group and identify five additional extremely low surface brightness candidate ultrafaint dwarfs that reach deep into the ultrafaint regime to M  V  ~ - 6 (similar to current limits for Andromeda satellites). These candidates' luminosities and sizes are similar to known Local Group dwarf galaxies Tucana B, Canes Venatici I, Hercules, and Boötes I. Most of these candidates are likely to be real, based on tests of our techniques on blank fields. Intriguingly, all of these candidates are spatially clustered around NGC 3077, which is itself an M81 group satellite in an advanced state of tidal disruption. This is somewhat surprising, as M81 itself and its largest satellite M82 are both substantially more massive than NGC 3077 and, by virtue of their greater masses, would have been expected to host as many or more ultrafaint candidates. These results lend considerable support to the idea that satellites of satellites are an important contribution to the growth of satellite populations around Milky Way-mass galaxies.

Keywords: Dwarf galaxies, Galaxy groups, Dwarf spheroidal galaxies
Turbulent Dust-trapping Rings as Efficient Sites for Planetesimal Formation. Recent observations of protoplanetary disks (PPDs) at submillimeter wavelengths have revealed the ubiquity of annular substructures that are indicative of pebble-sized dust particles trapped in turbulent ringlike gas pressure bumps. This major paradigm shift also challenges the leading theory of planetesimal formation from such pebbles by means of the streaming instability, which operates in a pressure gradient and can be suppressed by turbulence. Here, we conduct 3D local shearing box nonideal magnetohydrodynamic simulations of dust trapping in enforced gas pressure bumps, including dust backreaction. Under a moderate level of turbulence generated by the magnetorotational instability with ambipolar diffusion, which is suitable for outer disk conditions, we achieve quasi-steady states of dust trapping balanced by turbulent diffusion. We find strong dust clumping in all simulations near the gas pressure maxima, reaching a maximum density well above the threshold for triggering gravitational collapse to form planetesimals. A strong pressure bump concentrates dust particles toward the bump's center. With a weak pressure bump, dust can also concentrate in secondary filaments off the bump's center, due to dust backreaction, but strong clumping still occurs mainly in the primary ring around the bump's center. Our results reveal dust-trapping rings to be robust locations for planetesimal formation in outer PPDs, while they may possess diverse observational properties.

Keywords: Magnetohydrodynamics, Protoplanetary disks, Planet formation, Planetesimals
Unveiling the Contribution of Population III Stars in Primeval Galaxies at Redshift ≥6. Detection of the first stars has remained elusive so far but their presence may soon be unveiled by upcoming JWST observations. Previous studies have not investigated the entire possible range of halo masses and redshifts that may help in their detection. Motivated by the prospects of detecting galaxies up to z ~ 20 in the JWST early data release, we quantify the contribution of Population III stars to high-redshift galaxies from 6 ≤ z ≤ 30 by employing the semianalytical model A-SLOTH, which self-consistently models the formation of Population III and Population II stars along with their feedback. Our results suggest that the contribution of Population III stars is the highest in low-mass halos of 107-109 M ⊙. While high-mass halos ≥1010 M ⊙ contain less than 1% Population III stars, they host galaxies with stellar masses of 109 M ⊙ as early as z ~ 30. Interestingly, overall the apparent magnitude of Population III stars gets brighter toward higher redshift due to the higher stellar masses, but Population III-dominated galaxies are too faint to be directly detected with JWST. Our results predict JWST can detect galaxies up to z ~ 30, which may help in constraining the initial mass function of Population III stars and will guide observers to discern the contribution of Population III stars to high-redshift galaxies.

Keywords: Population II stars, Population III stars, High-redshift galaxies