adsabs/SciX_UAT_keywords huggingface dataset:
A Gap-sharing Planet Pair Shaping the Crescent in HD 163296: A Disk Sculpted by a Resonant Chain

The Atacama Large Millimeter Array observations of the disk around HD 163296 have resolved a crescent-shape substructure at around 55 au, inside and off-center from a gap in the dust that extends from 38 to 62 au. In this work we propose that both the crescent and the dust rings are caused by a compact pair (period ratio ≃4:3) of sub-Saturn-mass planets inside the gap, with the crescent corresponding to dust trapped at the L 5 Lagrange point of the outer planet. This interpretation also reproduces well the gap in the gas recently measured from the CO observations, which is shallower than what is expected in a model where the gap is carved by a single planet. Building on previous works arguing for outer planets at ≈86 and ≈137 au, we provide a global model of the disk that best reproduces the data and shows that all four planets may fall into a long resonant chain, with the outer three planets in a 1:2:4 Laplace resonance. We show that this configuration is not only an expected outcome from disk-planet interaction in this system, but it can also help constrain the radial and angular position of the planet candidates using three-body resonances.

Keywords: protoplanetary disks; planet formation; radiative transfer simulations; hydrodynamical simulations; planetary dynamics; dust continuum emission; planetary system evolution; planetary-disk interactions
Effects of Magnetic Fields in Hot White Dwarfs

In this work, we study the effects of magnetic fields on hot white dwarfs. We model their interior as a nuclei lattice surrounded by a relativistic free Fermi gas of electrons, accounting for effects from temperature, Landau levels, and anomalous magnetic moment. We find that, at low densities (corresponding to the outer regions of star), both temperature and magnetic field effects play an important role in the calculation of microscopic thermodynamical quantities. To study macroscopic stellar structures within a general-relativistic approach, we numerically solve the coupled Einstein-Maxwell equations for fixed entropy per particle configurations and discuss how temperature affects stellar magnetic field profiles, masses, and radii.

Keywords: stellar magnetic fields; white dwarf stars; degenerate matter; general relativity
GRB 111209A/SN 2011kl: Collapse of a Supramassive Magnetar with r-mode Oscillation and Fallback Accretion onto a Newborn Black Hole

Ultra-long-duration gamma-ray burst GRB 111209A was found to be associated with a very luminous supernovae (SNe) SN 2011kl. The physics of GRB 111209A/SN 2011kl has been extensively studied in the literature, but such research has not yet settled down. By investigating in detail the characteristics of the X-ray light curve of GRB 111209A, coupled with the temporal and spectral features observed in SN 2011kl, we argue that a short-lived supramassive magnetar could be responsible for the initial shallow X-ray emission. Then the electromagnetic extraction of spin energy from a black hole (BH) results in the steeply declining X-ray flux when the magnetar collapses into a BH. A fraction of the envelope materials falls back and activates the accretion onto the newborn BH, which produces the X-ray rebrightening bump at late times. During this process, a centrifugally driven baryon-rich quasi-isotropic Blandford & Payne outflow from the revived accretion disk deposits its kinetic energy on the SN ejecta, which powers luminous SN 2011kl. Finally, we place a limitation on the magnetar's physical parameters based on the observations.

Keywords: gamma-ray bursts; magnetars
Search for Magnetic Accretion in SW Sextantis Systems

SW Sextantis systems are nova-like cataclysmic variables that have unusual spectroscopic properties, which are thought to be caused by an accretion geometry having part of the mass flux trajectory out of the orbital plane. Accretion onto a magnetic white dwarf is one of the proposed scenarios for these systems. To verify this possibility, we analyzed photometric and polarimetric time-series data for a sample of six SW Sex stars. We report possible modulated circular polarization in BO Cet, SW Sex, and UU Aqr with periods of 11.1, 41.2, and 25.7 minutes, respectively, and less significant periodicities for V380 Oph at 22 minutes and V442 Oph at 19.4 minutes. We confirm previous results that LS Peg shows variable circular polarization. However, we determine a period of 18.8 minutes, which is different from the earlier reported value. We interpret these periods as the spin periods of the white dwarfs. Our polarimetric results indicate that 15% of the SW Sex systems have direct evidence of magnetic accretion. We also discuss SW Sex objects within the perspective of being magnetic systems, considering the latest findings about the demography, formation, and evolution of cataclysmic variables.

Keywords: cataclysmic variable stars; nova-like variable stars; magnetic variable stars; polarimetry; photometry
Fresh Insights on the Kinematics of M49's Globular Cluster System with MMT/Hectospec Spectroscopy

We present the first results of an MMT/Hectospec campaign to measure the kinematics of globular clusters (GCs) around M49-the brightest galaxy in the Virgo galaxy cluster, which dominates the Virgo B subcluster. The data include kinematic tracers beyond 95 kpc (~5.2 effective radii) for M49 for the first time, enabling us to achieve three key insights reported here. First, beyond ~20'-30' (~100-150 kpc), the GC kinematics sampled along the minor photometric axis of M49 become increasingly hotter, indicating a transition from GCs related to M49 to those representing the Virgo B intra-cluster medium. Second, there is an anomaly in the line-of-sight radial velocity dispersion (σr,los) profile in an annulus ~10-15' (~50-90 kpc) from M49 in which the kinematics cool by Δσr,los ≈ 150 km s-1 relative to those in- or outward. The kinematic fingerprint of a previous accretion event is hinted at in projected phase-space, and we isolate GCs that both give rise to this feature, and are spatially co-located with two prominent stellar shells in the halo of M49. Third, we find a subsample of GCs with velocities representative of the dwarf galaxy VCC 1249 that is currently interacting with M49. The spatial distribution of these GCs closely resembles the morphology of VCC 1249's isophotes, indicating that several of these GCs are likely in the act of being stripped from the dwarf during its passage through M49's halo. Taken together, these results point toward the opportunity of witnessing ongoing giant halo assembly in the depths of a cluster environment.

Keywords: globular star clusters; dwarf galaxies; giant elliptical galaxies; galaxy clusters
CME-associated Energetic Ions at 0.23 au: Consideration of the Auroral Pressure Cooker Mechanism Operating in the Low Corona as a Possible Energization Process

We draw a comparison between a solar energetic particle event associated with the release of a slow coronal mass ejection close to the Sun, and the energetic particle population produced in high current density field-aligned current structures associated with auroral phenomena in planetary magnetospheres. We suggest that this process is common in CME development and lift off in the corona, and may account for the electron populations that generate Type III radio bursts, as well as for the prompt energetic ion and electron populations typically observed in interplanetary space.

Keywords: solar energetic particles; solar coronal mass ejections; solar flares
White Dwarf Subsystems in Core-Collapsed Globular Clusters

Numerical and observational evidence suggests that massive white dwarfs dominate the innermost regions of core-collapsed globular clusters by both number and total mass. Using NGC 6397 as a test case, we constrain the features of white dwarf populations in core-collapsed clusters, both at present day and throughout their lifetimes. The dynamics of these white dwarf subsystems have a number of astrophysical implications. We demonstrate that the collapse of globular cluster cores is ultimately halted by the dynamical burning of white dwarf binaries. We predict that core-collapsed clusters in the local universe yield a white dwarf merger rate of ${ \mathcal O }(10)\,{{\rm{Gpc}}}^{-3}\,{{\rm{yr}}}^{-1}$ , roughly 0.1%-1% of the observed Type Ia supernova rate. We show that prior to merger, inspiraling white dwarf binaries will be observable as gravitational-wave sources at millihertz and decihertz frequencies. Over 90% of these mergers have a total mass greater than the Chandrasekhar limit. We argue that the merger/collision remnants, if not destroyed completely in an explosive transient, may be observed in core-collapsed clusters either as young neutron stars/pulsars/magnetars (in the event of accretion-induced collapse) or as young massive white dwarfs offset from the standard white dwarf cooling sequence. Finally, we show that collisions between white dwarfs and main-sequence stars, which may be detectable as bright transients, occur at a rate of ${ \mathcal O }(100)\,{{\rm{Gpc}}}^{-3}\,{{\rm{yr}}}^{-1}$ in the local universe. We find that these collisions lead to depletion of blue straggler stars and main-sequence star binaries in the centers of core-collapsed clusters.

Keywords: white dwarf stars; globular star clusters; type ia supernovae; stellar dynamics; gravitational wave astronomy
Stellar Collisions in Galactic Nuclei: Impact on Destructive Events Near a Supermassive Black Hole

The centers of galaxies host both a supermassive black hole and a dense stellar cluster. Such an environment should lead to stellar collisions, possibly at very high velocities so that the total energy involved is of the same order as supernova explosions. We present a simplified numerical analysis of the destructive stellar collision rate in a cluster similar to that of the Milky Way. The analysis includes an effective average two-body relaxation Monte Carlo scheme and general relativistic effects, as used by Sari & Fargione, to which we added explicit tracking of local probabilities for stellar collisions. We also consider stars which are injected into the stellar cluster after being disrupted from a binary system by the supermassive black hole. Such stars are captured in the vicinity of the black hole and enhance the expected collision rate. In our results we examine the rate and energetic distribution function of high-velocity stellar collisions, and compare them self-consistently with the other destructive processes which occur in the galactic center, namely tidal disruptions and extreme mass ratio inspirals.

Keywords: galactic center; supermassive black holes; stellar dynamics; analytical mathematics; computational methods; transient sources
Intrinsic Mass–Richness Relation of Clusters from THE THREE HUNDRED Hydrodynamic Simulations

The main systematics in cluster cosmology is the uncertainty in the mass–observable relation. In this paper, we focus on the most direct cluster observable in optical surveys, i.e., richness, and constrain the intrinsic mass–richness (MR) relation of clusters in THE THREE HUNDRED hydrodynamic simulations with two runs: GIZMO-SIMBA and GADGET-X. We find that modeling the richness at a fixed halo mass with a skewed Gaussian distribution yields a simpler and smaller scatter compared to the commonly used lognormal distribution. Additionally, we observe that baryon models have a significant impact on the scatter while exhibiting no influence on the mass dependence and a slight effect on the amplitude in the MR relation. We select member galaxies based on both stellar mass M ⋆ and absolute magnitude ${\mathscr{M}}$ . We demonstrate that the MR relations obtained from these two selections can be converted to each other by using the ${M}_{\star }\mbox{--}{\mathscr{M}}$ relation. Finally, we provide a seven-parameter fitting result comprehensively capturing the dependence of the MR relation on both stellar mass cutoff and redshift.

Keywords: galaxy clusters
New and Improved Lyα Reconstructions for M and K Dwarfs

The Lyα emission line is the brightest UV emission line in M and K dwarf spectra and serves as an important tool for studies of stellar chromospheres, the interstellar medium, and exoplanet atmospheres. However, Lyα observations have proven difficult due to the strong absorption by the interstellar medium, necessitating a reconstruction of the intrinsic stellar line from the observed spectrum. We have performed new Lyα reconstructions on the MUSCLES Treasury Survey stars, incorporating improved parameterizations for the intrinsic line wings and line core. We present an analysis of how the updated Lyα fluxes could impact photochemical and atmospheric escape studies and flux-flux scaling relations with other chromospheric emission lines such as Ca II H and K. We find the overall intrinsic Lyα flux of our star sample decreases by as little as 10% to as much as ~5× fainter compared to previous findings. The exception to this flux decrease is the M dwarf GJ 581, whose Lyα flux increased by 4%. These results will likely have a limited impact on the aforementioned studies that rely on Lyα fluxes.

Keywords: stellar activity; interstellar medium; exoplanets; ultraviolet astronomy; low mass stars
An AGN with an Ionized Gas Outflow in a Massive Quiescent Galaxy in a Protocluster at z = 3.09

We report the detection of an ionized gas outflow from an X-ray active galactic nucleus hosted in a massive quiescent galaxy in a protocluster at z = 3.09 (J221737.29+001823.4). It is a type-2 QSO with broad (W 80 > 1000 km s-1) and strong ( $\mathrm{log}({L}_{[\mathrm{OIII}]}$ /erg s-1) ≈ 43.4) [O III]λ λ 4959,5007 emission lines detected by slit spectroscopy in three-position angles using Multi-Object Infra-Red Camera and Spectrograph (MOIRCS) on the Subaru telescope and the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) on the Keck-I telescope. In the all slit directions, [O III] emission is extended to ~15 physical kpc and indicates a powerful outflow spreading over the host galaxy. The inferred ionized gas mass outflow rate is 22 ± 3 M ⊙ yr-1. Although it is a radio source, according to the line diagnostics using Hβ, [O II], and [O III], photoionization by the central QSO is likely the dominant ionization mechanism rather than shocks caused by radio jets. On the other hand, the spectral energy distribution of the host galaxy is well characterized as a quiescent galaxy that has shut down star formation several hundred Myr ago. Our results suggest a scenario that QSOs are powered after the shutdown of the star formation and help complete the quenching of massive quiescent galaxies at high redshift.

Keywords: active galactic nuclei; galaxy evolution; protoclusters
Implications for the Formation of (155140) 2005 UD from a New Convex Shape Model

(155140) 2005 UD has a similar orbit to (3200) Phaethon, an active asteroid in a highly eccentric orbit thought to be the source of the Geminid meteor shower. Evidence points to a genetic relationship between these two objects, but we have yet to fully understand how 2005 UD and Phaethon could have separated into this associated pair. Presented herein are new observations of 2005 UD from five observatories that were carried out during the 2018, 2019, and 2021 apparitions. We implemented light curve inversion using our new data, as well as dense and sparse archival data from epochs in 2005-2021, to better constrain the rotational period and derive a convex shape model of 2005 UD. We discuss two equally well-fitting pole solutions (λ = 116.°6, β = -53.°6) and (λ = 300.°3, β = -55.°4), the former largely in agreement with previous thermophysical analyses and the latter interesting due to its proximity to Phaethon's pole orientation. We also present a refined sidereal period of P sid = 5.234246 ± 0.000097 hr. A search for surface color heterogeneity showed no significant rotational variation. An activity search using the deepest stacked image available of 2005 UD near aphelion did not reveal a coma or tail but allowed modeling of an upper limit of 0.04-0.37 kg s-1 for dust production. We then leveraged our spin solutions to help limit the range of formation scenarios and the link to Phaethon in the context of nongravitational forces and timescales associated with the physical evolution of the system.

Keywords: near-earth objects; ccd photometry; light curves
A Massive AGB Donor in Scutum X-1: Identification of the First Mira Variable in an X-Ray Binary

The symbiotic X-ray binary Sct X-1 was suggested to be the first known neutron star accreting from a red supergiant companion. Although known for nearly 50 yr, detailed characterization of the donor remains lacking, particularly due to the extremely high reddening toward the source (A V ≳ 25 mag). Here, we present (i) improved localization of the counterpart using Gaia and Chandra observations, (ii) the first broadband infrared spectrum (≈1-5 μm; R ≈ 2000) obtained with SpeX on the NASA Infrared Telescope Facility, and (iii) the J-band light curve from the Palomar Gattini-IR survey. The infrared spectrum is characterized by (i) deep water absorption features (H2O index ≈ 40%), (ii) strong TiO, VO, and CO features, and (iii) weak/absent CN lines. We show that these features are inconsistent with known red supergiants but suggest an M8-9 III-type O-rich Mira donor star. We report the discovery of large-amplitude (ΔJ ≈ 3.5 mag) periodic photometric variability, suggesting a pulsation period of 621 ± 36 (systematic) ± 8 (statistical) days, which we use to constrain the donor to be a relatively luminous Mira (M K = -8.6 ± 0.3 mag) at a distance of ${3.6}_{-0.7}^{+0.8}$ kpc. Comparing these characteristics to recent models, we find the donor to be consistent with a ≈3-5 M ⊙ star at an age of ≈0.1-0.3 Gyr. Together, we show that Sct X-1 was previously misclassified as an evolved high-mass X-ray binary; instead, it is an intermediate-mass system with the first confirmed Mira donor in an X-ray binary. We discuss the implications of Mira donors in symbiotic X-ray binaries and highlight the potential of wide-field infrared time-domain surveys and broadband infrared spectroscopy to unveil their demographics.

Keywords: x-ray binary stars; mira variable stars; sky surveys; asymptotic giant branch
The Strength of the 2175 Å Feature in the Attenuation Curves of Galaxies at 0.1 < z ≲ 3

We update the spectral modeling code MAGPHYS to include a 2175 Å absorption feature in its UV to near-IR dust attenuation prescription. This allows us to determine the strength of this feature and the shape of the dust attenuation curve in ∼5000 star-forming galaxies at $0.1\lt z\lesssim 3$ in the COSMOS field. We find that a 2175 Å absorption feature of ∼1/3 the strength of that in the Milky Way is required for models to minimize residuals. We characterize the total effective dust attenuation curves as a function of several galaxy properties and find that the UV slopes of the attenuation curve for COSMOS galaxies show a strong dependence on star formation rate (SFR) and total dust attenuation (AV), such that galaxies with higher SFR and AV have shallower curves and vice versa. These results are consistent with expectations from radiative transfer that attenuation curves become shallower as the effective dust optical depth increases. We do not find significant trends in the strength of the 2175 Å absorption feature as a function of galaxy properties, but this may result from the high uncertainties associated with this measurement. The updated code is publicly available online (following acceptance).

Keywords: galaxy evolution; interstellar dust; infrared galaxies; interstellar medium; interstellar dust extinction
Using the Starlight Polarization Efficiency Integral to Constrain Shapes and Porosities of Interstellar Grains

We have developed a new method for using the observed starlight polarization and polarized submillimeter emission to constrain the shapes and porosities of interstellar grains. We first present the modified picket-fence approximation and verify that it is sufficiently accurate for modeling starlight polarization. We then introduce the observed starlight polarization integral Πobs as a measure of the overall strength of the observed polarization of starlight, and the starlight polarization efficiency integral Φ to characterize the effectiveness of different grain types for producing polarization of starlight. The ratio Πobs/Φ determines the mass-weighted alignment ⟨falign⟩ of the grains. Approximating the aligned grains in the ISM as spheroids, we use Πobs/Φ to show that the observed starlight polarization constrains the grains to have a minimum degree of asphericity. For porosity ${ \mathcal P }=0$ , the minimum axial ratio is ~1.4 for oblate spheroids, or ~1.8 for prolate spheroids. If the grains are porous, more extreme axial ratios are required. The same grains that produce the starlight polarization are able to provide the observed polarized emission at submillimeter wavelengths but with further limits on shape and porosity. Porosities ${ \mathcal P }\gtrsim 0.75$ are ruled out. If interstellar grains can be approximated by "astrodust" spheroids, we predict the ratio of 10 μm polarization to starlight polarization pV: p(10 μm)/pV = 0.219 ± 0.029. For Cyg OB2-12, we predict p(10 μm) = (2.1 ± 0.3)%, which should be observable.

Keywords: dust continuum emission; starlight polarization; silicate grains; far infrared astronomy; interstellar dust extinction
Absorption Line Oscillator Strengths for the C 2Π(0)-A 2Σ+(0) Band of Nitric Oxide

We have determined absorption oscillator strengths for rotational transitions of the C 2Π(0)-A 2Σ+(0) band of NO, which has been detected in the upper atmosphere of Venus. The molecular quantum defect orbital method has been used in the calculation of the electronic transition moment and the Rydberg-valence interaction between the C 2Π(v = 0) and the B 2Π (v = 7) states has been considered. Considerable deviations from normal intensity distribution of the rotational lines have been found at J ≤ 5.5. As far as we know, the present line f-values are reported here for the first time. These data may be useful in the interpretation of the observations obtained by the Visible and Infrared Thermal Imaging Spectrometer instrument on the Venus Express spacecraft.

Keywords: molecular spectroscopy; line intensities
Mapping the Escape Fraction of Ionizing Photons Using Resolved Stars: A Much Higher Escape Fraction for NGC 4214

We demonstrate a new method for measuring the escape fraction of ionizing photons using Hubble Space Telescope imaging of resolved stars in NGC 4214, a local analog of high-redshift starburst galaxies that are thought to be responsible for cosmic reionization. Specifically, we forward model the UV through near-IR spectral energy distributions of ∼83,000 resolved stars to infer their individual ionizing flux outputs. We constrain the local escape fraction by comparing the number of ionizing photons produced by stars to the number that are either absorbed by dust or consumed by ionizing the surrounding neutral hydrogen in individual star-forming regions. We find substantial spatial variation in the escape fraction (0%-40%). Integrating over the entire galaxy yields a global escape fraction of ${25}_{-15}^{+16}$ %. This value is much higher than previous escape fractions of zero reported for this galaxy. We discuss the sources of this apparent tension and demonstrate that the viewing angle and 3D interstellar medium geometric effects are the cause. If we assume that NGC 4214 has no internal dust, like many high-redshift galaxies, we find an escape fraction of 59% (an upper limit for NGC 4214). This is the first nonzero escape fraction measurement for UV-faint (M ${}_{\mathrm{FUV}}$ = -15.9) galaxies at any redshift and supports the idea that starburst UV-faint dwarf galaxies can provide a sufficient number of ionizing photons to the intergalactic medium.

Keywords: dwarf irregular galaxies; galaxy evolution; galaxy formation; star formation; interstellar medium; reionization