adsabs/SciX_UAT_keywords huggingface dataset:
Joint Constraints on Exoplanetary Orbits from Gaia DR3 and Doppler Data

The third Gaia data release includes a catalog of exoplanets and exoplanet candidates identified via the star's astrometric motion. This paper reports on tests for consistency between the Gaia two-body orbital solutions and precise Doppler velocities for stars currently amenable to such a comparison. For BD-17 0063, HD 81040, and HD 132406, the Gaia orbital solution and the Doppler data were found to be consistent and were fitted jointly to obtain the best possible constraints on the planets' orbits and masses. Inconsistencies were found for four stars: HD 111232, probably due to additional planets that were not included in the astrometric model; HD 175167 and HR 810, possibly due to inaccurate treatment of non-Gaussian uncertainties in the Gaia orbital solutions; and HIP 66074, for unknown reasons. Consistency tests were also performed for HD 114762, which was reported in 1989 to have a brown dwarf or exoplanet but has since been shown to be a binary star. The joint Gaia-Doppler analysis shows the secondary mass to be 0.215 ± 0.013 M ⊙ and the orbital inclination to be 3.°63 ± 0.°06.

Keywords: exoplanet astronomy; extrasolar gaseous giant planets; exoplanets; astrometry; radial velocity; orbit determination
Scattering Delay Mitigation in High-accuracy Pulsar Timing: Cyclic Spectroscopy Techniques

We simulate scattering delays from the interstellar medium to examine the effectiveness of three estimators in recovering these delays in pulsar timing data. Two of these estimators use the more traditional process of fitting autocorrelation functions to pulsar dynamic spectra to extract scintillation bandwidths, while the third estimator uses the newer technique of cyclic spectroscopy on baseband pulsar data to recover the interstellar medium's impulse response function. We find that either fitting a Lorentzian or Gaussian distribution to an autocorrelation function or recovering the impulse response function from the cyclic spectrum are, on average, accurate in recovering scattering delays, although autocorrelation function estimators have a large variance, even at high signal-to-noise ratio (S/N). We find that, given sufficient S/N, cyclic spectroscopy is more accurate than both Gaussian and Lorentzian fitting for recovering scattering delays at specific epochs, suggesting that cyclic spectroscopy is a superior method for scattering estimation in high-quality data.

Keywords: interstellar medium; pulsar timing method; radio pulsars; interstellar scattering
Orb_It: A Validation Package for Orbit Integrators

We present a testing platform and package that can validate the accuracy of an orbit integrator. Orb_It is written in Python and is capable of validating the most heavily used orbital integrators such as Find_Orb, OpenOrb, and OrbFit. Orb_It performs an "end-to-end" test of each integrator to check for internal consistency of the integrators functions. For a given objects state vector and epoch, Orb_It uses a user-specified integrator to generate the objects ephemeris for a specified time range and observer, uses those ephemerides as observations to fit an orbit, and then compares that fitted orbit to the original input state vector propagated to the fitted orbits epoch. This allows users to understand the internal accuracy of each integrator. This testing suite and package can be found on GitHub with a demo on Binder (https://github.com/B612-Asteroid-Institute/orb_it).

Keywords: asteroids; astronomy software; orbit determination; small solar system bodies; ephemerides
Impact of Electron Precipitation on Brown Dwarf Atmospheres and the Missing Auroral {{H}}_{3}(+) Emission

Recent observations have demonstrated that very low-mass stars and brown dwarfs are capable of sustaining strong magnetic fields despite their cool and neutral atmospheres. These kilogauss field strengths are inferred based on strong, highly circularly polarized gigahertz radio emission, a consequence of the electron cyclotron maser instability. Crucially, these observations imply the existence of energetic nonthermal electron populations, associated with strong current systems, as are found in the auroral regions of the magnetized planets of the solar system. Intense auroral electron precipitation will lead to electron collisions with the H2 gas that should generate the ion ${{\rm{H}}}_{3}^{+}$ . With this motivation, we targeted a sample of ultracool dwarfs, known to exhibit signatures associated with aurorae, in search of the K-band emission features of ${{\rm{H}}}_{3}^{+}$ using the Keck telescopes on Maunakea. From our sample of nine objects, we found no clear indication of ${{\rm{H}}}_{3}^{+}$ emission features in our low-to-medium-resolution spectra (R ∼ 3600). We also modeled the impact of an auroral electron beam on a brown dwarf atmosphere, determining the depth at which energetic beams deposit their energy and drive particle impact ionization. We find that the ${{\rm{H}}}_{3}^{+}$ nondetections can be explained by electron beams of typical energies ≳2–10 keV, which penetrate deeply enough that any ${{\rm{H}}}_{3}^{+}$ produced is chemically destroyed before radiating energy through its infrared transitions. Strong electron beams could further explain the lack of UV auroral detections and suggest that most or nearly all of the precipitating auroral energy must ultimately emerge as thermal emissions deep in brown dwarf atmospheres.

Keywords: brown dwarfs; m dwarf stars; aurorae
The JWST Discovery of the Triply Imaged Type Ia "Supernova H0pe" and Observations of the Galaxy Cluster PLCK G165.7+67.0

A Type Ia supernova (SN) at z = 1.78 was discovered in James Webb Space Telescope Near Infrared Camera imaging of the galaxy cluster PLCK G165.7+67.0 (G165; z = 0.35). The SN is situated 1.5–2 kpc from the host-galaxy nucleus and appears in three different locations as a result of gravitational lensing by G165. These data can yield a value for Hubble's constant using time delays from this multiply imaged SN Ia that we call "SN H0pe." Over the cluster, we identified 21 image multiplicities, confirmed five of them using the Near-Infrared Spectrograph, and constructed a new lens model that gives a total mass within 600 kpc of (2.6 ± 0.3) × 1014 M ⊙. The photometry uncovered a galaxy overdensity coincident with the SN host galaxy. NIRSpec confirmed six member galaxies, four of which surround the SN host galaxy with relative velocity ≲900 km s‑1 and projected physical extent ≲33 kpc. This compact galaxy group is dominated by the SN host galaxy, which has a stellar mass of (5.0 ± 0.1) × 1011 M ⊙. The group members have specific star formation rates of 2–260 Gyr‑1 derived from the Hα-line fluxes corrected for stellar absorption, dust extinction, and slit losses. Another group centered on a strongly lensed dusty star-forming galaxy is at z = 2.24. The total (unobscured and obscured) SFR of this second galaxy group is estimated to be (≳ 100 M ⊙ yr‑1), which translates to a supernova rate of ∼1 SNe yr‑1, suggesting that regular monitoring of this cluster may yield additional SNe.

Keywords: strong gravitational lensing; rich galaxy clusters; high-redshift galaxy clusters; galaxy cluster counts; galaxy spectroscopy
Rotational Components of the Sun's Mean Field

This paper uses wavelet transforms to look for the rotational frequencies of the Sun's mean line-of-sight magnetic field. For a sufficiently high wavelet frequency, the spectra of the dipole, quadrupole, and hexapole field components each show a time-dependent fine structure with periods in the range of 26.5-30 days and their harmonics. These maps confirm that a large enhancement of power at 30 days occurred in the dipole field during 1989-1990, as recorded previously using Fourier techniques. In addition, during some years the maps show power at 26.5 days (or its harmonics), which is clearly distinguishable from the rotation period of 26.9-27.0 days at the Sun's equator. In at least one case, the 26.5-day period was a wave phenomenon caused by the systematic eruption of active regions at progressively more western locations in the Carrington coordinate system, as if the flux were emerging from a fixed longitude in a faster-rotating subsurface layer. Based on previous studies of the mean field, I conclude that the enhanced wavelet patterns in this paper are regions where magnetic flux is emerging in configurations that strengthen the Sun's horizontal dipole, quadrupole, and hexapole fields, and (in the case of the more slowly rotating patterns) where this flux is being transported to midlatitudes whose rotation periods are in the range of 28-30 days.

Keywords: solar magnetic fields; solar rotation; solar cycle; stellar magnetic fields
Discovery and Timing of Three Millisecond Pulsars in Radio and Gamma-Rays with the Giant Metrewave Radio Telescope and Fermi Large Area Telescope

We performed deep observations to search for radio pulsations in the directions of 375 unassociated Fermi Large Area Telescope γ-ray sources using the Giant Metrewave Radio Telescope (GMRT) at 322 and 607 MHz. In this paper we report the discovery of three millisecond pulsars (MSPs), PSR J0248+4230, PSR J1207-5050, and PSR J1536-4948. We conducted follow-up timing observations for ∼5 yr with the GMRT and derived phase-coherent timing models for these MSPs. PSR J0248+4230 and J1207-5050 are isolated MSPs having periodicities of 2.60 ms and 4.84 ms. PSR J1536-4948 is a 3.07 ms pulsar in a binary system with an orbital period of ∼62 days about a companion of a minimum mass of 0.32 M⊙. We also present multifrequency pulse profiles of these MSPs from the GMRT observations. PSR J1536-4948 is an MSP with an extremely wide pulse profile having multiple components. Using the radio timing ephemeris we subsequently detected γ-ray pulsations from these three MSPs, confirming them as the sources powering the γ-ray emission. For PSR J1536-4948 we performed combined radio-γ-ray timing using ∼11.6 yr of γ-ray pulse times of arrival (TOAs) along with the radio TOAs. PSR J1536-4948 also shows evidence for pulsed γ-ray emission out to above 25 GeV, confirming earlier associations of this MSP with a ≥10 GeV point source. The multiwavelength pulse profiles of all three MSPs offer challenges to models of radio and γ-ray emission in pulsar magnetospheres.

Keywords: high energy astrophysics; high time resolution astrophysics; millisecond pulsars; radio astronomy; gamma-ray astronomy; binary pulsars
Probing Accretion Turbulence in the Galactic Center with EHT Polarimetry

Magnetic fields grown by instabilities driven by differential rotation are believed to be essential to accretion onto black holes. These instabilities saturate in a turbulent state; therefore, the spatial and temporal variability in the horizon-resolving images of Sagittarius A* (Sgr A*) will be able to empirically assess this critical aspect of accretion theory. However, interstellar scattering blurs high-frequency radio images from the Galactic center and introduces spurious small-scale structures, complicating the interpretation of spatial fluctuations in the image. We explore the impact of interstellar scattering on the polarized images of Sgr A* and demonstrate that for credible physical parameters, the intervening scattering is non-birefringent. Therefore, we construct a scattering mitigation scheme that exploits horizon-resolving polarized millimeter/submillimeter VLBI observations to generate statistical measures of the intrinsic spatial fluctuations and therefore the underlying accretion flow turbulence. An optimal polarization basis is identified, corresponding to measurements of the fluctuations in magnetic field orientation in three dimensions. We validate our mitigation scheme using simulated data sets and find that current and future ground-based experiments will readily be able to accurately measure the image-fluctuation power spectrum.

Keywords: interstellar scattering; radio interferometry; polarimetry; very long baseline interferometry
Proton Perpendicular Heating in Turbulence Simulations: Determination of the Velocity Diffusion Coefficient

Numerical methods are presented that can determine the perpendicular velocity space diffusion coefficient from kinetic simulation results. The methods are applied to hybrid simulation results using particle protons and a massless, quasi-neutralizing electron fluid for a case of quasi-perpendicular turbulence. During the quasi-steady phase of the turbulence, the evolution of the grid-averaged, gyrotropic, and peculiar velocity distribution of protons with velocity components perpendicular to the background magnetic field is found to be adequately described by diffusion. The estimated diffusion coefficient varies with perpendicular proton speed. A relative maximum occurs at a speed of zero. About the thermal speed, the coefficient decreases with increasing speed consistent with a power law with index -3. A relative minimum occurs at larger speeds, and the diffusion coefficient rises among the fastest protons contained in the simulation. The functional form of the diffusion coefficient appears to be the result of two sources. At speeds less than the relative minimum, the diffusion is dominated by turbulence generated fluctuations, while at greater speeds the diffusion arises from the large-scale fluctuations that initiated the turbulent energy cascade. Results are compared with theoretical predictions for the diffusion coefficient and with results presented from a previous simulation. Implications for generating suprathermal protons from quasi-perpendicular turbulence are also discussed.

Keywords: solar wind; interplanetary turbulence; space plasmas
Multiwavelength Pulsations and Surface Temperature Distribution in the Middle-aged Pulsar B1055–52

We present a detailed study of the X-ray emission from PSR B1055–52 using XMM-Newton observations from 2019 and 2000. The phase-integrated X-ray emission from this pulsar is poorly described by existing models of neutron star atmospheres. Instead, we confirm that, similar to other middle-aged pulsars, the best-fitting spectral model consists of two blackbody components, with substantially different temperatures and emitting areas, and a nonthermal component characterized by a power law. Our phase-resolved X-ray spectral analysis using this three-component model reveals variations in the thermal emission parameters with the pulsar's rotational phase. These variations suggest a nonuniform temperature distribution across the neutron star's surface, including the cold thermal component and probable hot spot(s). Such a temperature distribution can be caused by external and internal heating processes, likely a combination thereof. We observe very high pulse fractions, 60%–80% in the 0.7–1.5 keV range, dominated by the hot blackbody component. This could be related to temperature nonuniformity and potential beaming effects in an atmosphere. We find indication of a second hot spot that appears at lower energies (0.15–0.3 keV) than the first hot spot (0.5–1.5 keV) in the X-ray light curves and is offset by about half a rotation period. This finding aligns with the nearly orthogonal rotator geometry suggested by radio observations of this interpulse pulsar. If the hot spots are associated with polar caps, a possible explanation for their temperature asymmetry could be an offset magnetic dipole and/or an additional toroidal magnetic field component in the neutron star crust.

Keywords: neutron stars; pulsars; compact objects; x-ray astronomy; high energy astrophysics
The New Swift/UVOT+MaNGA (SwiM) Value-added Catalog

We present the the new Swift/UVOT+MaNGA (SwiM) catalog (SwiM_v4.1). SwiM_v4.1 is designed to study star formation and dust attenuation within nearby galaxies given the unique overlap of Swift/UVOT near-ultraviolet (NUV) imaging and MaNGA integral field optical spectroscopy. SwiM_v4.1 comprises 559 objects, ∼4 times more than the original SwiM catalog (SwiM_v3.1), spans the redshift range z ≈ 0.0002–0.1482, and provides a more diverse and rich sample. Approximately 5% of the final MaNGA sample is included in SwiM_v4.1, and 42% of the SwiM_v4.1 galaxies are cross-listed with other well-known catalogs. We present the same data as SwiM_v3.1, including UVOT images, Sloan Digital Sky Survey (SDSS) images, and MaNGA emission-line and spectral index maps with the same pixel size and angular resolution for each galaxy, and a file containing galaxy and observational properties. We designed SwiM_v4.1 to be unbiased, which resulted in some objects having low signal-to-noise ratios in their MaNGA or Swift data. We addressed this by providing a new file containing the fraction of science-ready pixels in each MaNGA emission-line map, and the integrated flux and inverse variance for all three NUV filters. The uniform angular resolution and sampling in SwiM_v4.1 will help answer a number of scientific questions, including constraining quenching and attenuation in the local Universe and studying the effects of black hole feedback. The galaxy maps, catalog files, and their associated data models are publicly released on the SDSS website (a description of the SwiM VAC is provided at https://www.sdss4.org/dr17/data_access/value-added-catalogs/?vac_id=swift-manga-value-added-catalog, and the data are stored on the SDSS Science Archive Server at https://data.sdss.org/sas/dr17/manga/swim/v4.1/).

Keywords: catalogs; galaxies; astronomy data analysis; sloan photometry; ultraviolet photometry; spectroscopy; star formation
Comparing the VANDELS Sample to a Zoom-in Radiative Hydrodynamical Simulation: Using the Si II and C II Line Spectra as Tracers of Galaxy Evolution and Lyman Continuum Leakage

We compare mock ultraviolet C II and Si II absorption and emission line features generated using a ∼109 M ⊙ virtual galaxy with observations of 131 z ∼ 3 galaxies from the VANDELS survey. We find that the mock spectra reproduce reasonably well a large majority (83%) of the VANDELS spectra (χ 2 < 2), but do not resemble the most massive objects (⪆1010 M ⊙), which exhibit broad absorption features. Interestingly, the best-matching mock spectra originate from periods of intense star formation in the virtual galaxy, where its luminosity is 4 times higher than in periods of relative quiescence. Furthermore, for each galaxy, we predict the Lyman continuum (LyC) escape fractions ( ) using the environment of the virtual galaxy. We derive an average of 0.01 ± 0.02, consistent with other estimates from the literature. The are tightly correlated with the Lyα escape fractions and highly consistent with observed empirical trends. Additionally, galaxies with larger exhibit bluer β slopes, more Lyα flux, and weaker low-ionization absorption lines. Building upon the good agreement between and observationally established LyC diagnostics, we examine the LyC leakage mechanisms in the simulation. We find that LyC photon leakage is enhanced in directions where the observed flux dominantly emerges from compact regions depleted of neutral gas and dust, mirroring the scenario inferred from observational data. In general, this study further highlights the potential of high-resolution radiation hydrodynamics simulations in analyzing UV absorption and emission line features and providing valuable insights into the LyC leakage of star-forming galaxies.

Keywords: ultraviolet astronomy; interstellar medium; starburst galaxies; galaxy evolution
Gas Dynamical Friction on Accreting Objects

The drag force experienced by astronomical objects moving through gaseous media (gas dynamical friction) plays a crucial role in their orbital evolution. Ostriker derived a formula for gas dynamical friction by linear analysis, and its validity has been confirmed through subsequent numerical simulations. However, the effect of gas accretion onto the objects on the dynamical friction is yet to be understood. In this study, we investigate the Mach number dependence of dynamical friction considering gas accretion through three-dimensional nested-grid simulations. We find that the net frictional force, determined by the sum of the gravitational force exerted by surrounding gas and momentum flux transferred by accreting gas, is independent of the resolution of simulations. Only the gas outside the Bondi–Hoyle–Lyttleton radius contributes to dynamical friction, because the gas inside this radius is eventually absorbed by the central object and returns the momentum obtained through the gravitational interaction with it. In the subsonic case, the front–back asymmetry induced by gas accretion leads to larger dynamical friction than predicted by the linear theory. Conversely, in the slightly supersonic case with a Mach number between 1 and 1.5, the nonlinear effect leads to a modification of the density distribution in a way that reduces the dynamical friction, compared with the linear theory. At a higher Mach number, the modification becomes insignificant and the dynamical friction can be estimated with the linear theory. We also provide a fitting formula for dynamical friction based on our simulations, which can be used in a variety of applications.

Keywords: dynamical friction; hydrodynamics; black holes
Discovery of an Exceptional Optical Nebulosity in the Suspected Galactic SN Iax Remnant Pa 30 Linked to the Historical Guest Star of 1181 CE

A newly recognized young Galactic supernova (SN) remnant, Pa 30 (G123.1+4.6), centered on a hot central star with a ~16,000 km s-1 wind velocity, has recently been proposed to be the result of a double-degenerate merger leading to an SN Iax event associated with the guest star of 1181 CE. Here we present deep optical [S II] λλ6716,6731 images of Pa 30 that reveal an extraordinary and highly structured nebula 170″ in diameter with dozens of long (5″-20″), radially aligned filaments with a convergence point near the hot central star. Optical spectra of filaments indicate a peak expansion velocity ≃1100 km s-1 with electron densities of ≤100-700 cm-3 and a thick shell-like structure resembling its appearance in 22 μm WISE images. No Hα emission was seen ([S II] λ6716/Hα >5), with the only other line emission detected being faint [Ar III] λ7136, suggesting a S- and Ar-rich but H-poor remnant. The nebula's angular size, estimated 2.3 kpc distance, and 1100 km s-1 expansion velocity are consistent with an explosion date around 1181 CE. The remnant's unusual appearance may be due to the photoionization of wind-driven ejecta due to clump-wind interactions caused by the central star's high-luminosity wind.

Keywords: type ia supernovae; supernova remnants; emission nebulae; spectroscopy; circumstellar matter