adsabs/SciX_UAT_keywords huggingface dataset:
A Spectral Solver for Solar Inertial Waves

Inertial waves, which are predominantly driven by the Coriolis force, likely play an important role in solar dynamics, and, additionally, they provide a window into the solar subsurface. The latter allows us to infer properties that are inaccessible to the traditional technique of acoustic wave helioseismology. Thus, a full characterization of these normal modes holds the promise of enabling investigations into solar subsurface dynamics. In this work, we develop a spectral eigenvalue solver to model the spectrum of inertial waves in the Sun. We model the solar convection zone as an anelastic medium, and solve for the normal modes of the momentum and energy equations. We demonstrate that the solver can well reproduce the observed mode frequencies and line widths, not only of sectoral Rossby modes, but also of recently observed high-frequency inertial modes. In addition, we believe that the spectral solver is a useful contribution to the numerical methods of modeling inertial modes on the Sun.

Keywords: the sun; internal waves; astrophysical fluid dynamics; computational methods; computational astronomy
The Multiwavelength Counterparts of Fast Radio Bursts

The engines that produce extragalactic fast radio bursts (FRBs), and the mechanism by which the emission is generated, remain unknown. Many FRB models predict prompt multiwavelength counterparts, which can be used to refine our knowledge of these fundamentals of the FRB phenomenon. However, several previous targeted searches for prompt FRB counterparts have yielded no detections and have additionally not reached sufficient sensitivity with respect to the predictions. In this work, we demonstrate a technique to estimate the ratio, η, between the energy outputs of FRB counterparts at various wavelengths and the radio-wavelength emission. Our technique combines the fluence distribution of the FRB population with results from several wide-field blind surveys for fast transients from the optical to the TeV bands. We present constraints on η that improve upon previous observations even in the case where all unclassified transient events in existing surveys are FRB counterparts. In some scenarios for the FRB engine and emission mechanism, we find that FRB counterparts should have already been detected, thus demonstrating that our technique can successfully test predictions for η. However, it is possible that FRB counterparts are lurking among catalogs of unclassified transient events. Although our technique is robust to the present uncertainty in the FRB fluence distribution, its ultimate application to accurately estimate or bound η will require the careful analysis of all candidate fast transient events in multiwavelength survey data sets.

Keywords: radio bursts; neutron stars; radio transient sources
A Study of Twelve Potential Merger Candidate Contact Binary Systems

Photometric observations and analysis of twelve previously poorly studied contact binary systems is presented. All show total eclipses and have extremely low mass ratios ranging from 0.072 to 0.15. Also, all show characteristics of orbital instability with mass ratios within the theoretical orbital instability range. Although none demonstrate a significant O'Connell effect at least nine of the systems have other indicators of increased chromospheric and magnetic activity.

Keywords: contact binary stars; orbital elements; transient detection
Magnetic Reconnection Rate in the M6.5 Solar Flare on 2015 June 22

Magnetic reconnection is regarded as the mechanism for the rapid release of magnetic energy stored in active regions during solar flares, and quantitative measurements of the magnetic reconnection rate are essential for understanding solar flares. In the context of the standard two-ribbon flare model, we derive the coronal magnetic reconnection rate of the M6.5 flare on 2015 June 22 in two terms, reconnection flux change rate and reconnection electric field, both of which can be obtained from observations of the flare morphology. Data used include a sequence of chromospheric Hα images with unprecedented resolution during the flare from the Visual Imaging Spectrometer of the Goode Solar Telescope (GST) at the Big Bear Solar Observatory and a preflare line-of-sight photospheric magnetogram from the GST Near-InfraRed Imaging Spectropolarimeter along with hard X-ray data from the Ramaty High Energy Solar Spectroscopic Imager. The temporal correlation between the magnetic reconnection rate and nonthermal emission is found, and the variation of the reconnection electric field is mainly determined by the ribbon speed, not by the local magnetic field encountered by the ribbon front. Spatially, the hard X-ray source overlaps with the location of the strongest electric field obtained at the same time. The ribbon motion shows abundant fine structures, including a local acceleration at the location of a light bridge with a weaker magnetic field.

Keywords: solar flares; solar magnetic reconnection
The Preservation of Super-Earths and the Emergence of Gas Giants after Their Progenitor Cores Have Entered the Pebble-isolation Phase

The omnipresence of super-Earths suggests that they are able to be retained in natal disks around low-mass stars, whereas exoplanets' mass distributions indicate that some cores have transformed into gas giants through runaway gas accretion at ≳1 au from solar-type stars. In this paper, we show that transition to runaway gas accretion by cores may be self-impeded by an increase of the grain opacity in their envelope after they have acquired sufficient mass (typically ∼ 10M⊕) to enter a pebble-isolation phase. The accumulation of approximately millimeter- to meter-sized pebbles in their migration barriers enhances their local fragmentation rates. The freshly produced submillimeter grains pass through the barrier, elevate the effective dust opacity, and reduce the radiative flux in the core's envelope. These effects alone are adequate to suppress the transition to runaway accretion and preserve super-Earths in the stellar proximity (∼0.1 au), albeit entropy advection between the envelope and the disk can further reduce the accretion rate. At an intermediate distance (∼1 au) from their host stars, the escalation in the dust opacity dominates over entropy advection in stalling the transition to runaway accretion for marginally pebble-isolated cores. Beyond a few astronomical unit, the transformation of more-massive cores to gas giants is reachable before severe depletion of disk gas. This requirement can be satisfied either in extended disks with large scale height via orderly accretion of migrating pebbles or through the mergers of oligarchic protoplanetary embryos, and can account for the correlated occurrence of long-period gas giants and close-in super-Earths.

Keywords: protoplanetary disks; planet formation; accretion; super earths
Identifying the 3FHL Catalog. IV. Swift Observations of Unassociated Fermi-LAT 3FHL Sources

The Fermi Large Area Telescope (Fermi-LAT) 3FHL catalog is the latest catalog of >10 GeV sources and will remain an important resource for the high-energy community for the foreseeable future. Therefore, it is crucial that this catalog is made complete by providing associations for most sources. In this paper, we present the results of the X-ray analysis of 38 3FHL sources. We found a single bright X-ray source in 20 fields, two sources each in two fields, and none for the remaining 16. The analysis of the properties of the 22 3FHL fields with X-ray sources led us to believe that most (∼19/22) are of extragalactic origin. A machine-learning algorithm was used to determine the source type and we find that 15 potential blazars are likely BL Lacertae objects (BL Lac objects). This is consistent with the fact that BL Lac objects are by far the most numerous population detected above >10 GeV in the 3FHL.

Keywords: active galactic nuclei; blazars; gamma-ray astronomy; x-ray identification
Deep Synoptic Array Science: Polarimetry of 25 New Fast Radio Bursts Provides Insights into Their Origins

We report on a full-polarization analysis of the first 25 as yet nonrepeating fast radio bursts (FRBs) detected at 1.4 GHz by the 110-antenna Deep Synoptic Array (DSA-110) during commissioning observations. We present details of the data-reduction, calibration, and analysis procedures developed for this novel instrument. Faraday rotation measures (RMs) are searched between ±106 rad m‑2 and detected for 20 FRBs, with magnitudes ranging from 4 to 4670 rad m‑2. Fifteen out of 25 FRBs are consistent with 100% polarization, 10 of which have high (≥70%) linear-polarization fractions and two of which have high (≥30%) circular-polarization fractions. Our results disfavor multipath RM scattering as a dominant depolarization mechanism. Polarization-state and possible RM variations are observed in the four FRBs with multiple subcomponents. We combine the DSA-110 sample with polarimetry of previously published FRBs, and compare the polarization properties of FRB subpopulations and FRBs with Galactic pulsars. Although FRB polarization fractions are typically higher than those of Galactic pulsars, and cover a wider range than those of pulsar single pulses, they resemble those of the youngest (characteristic ages <105 yr) pulsars. Our results support a scenario wherein FRB emission is intrinsically highly linearly polarized, and propagation effects can result in conversion to circular polarization and depolarization. Young pulsar emission and magnetospheric propagation geometries may form a useful analogy for the origin of FRB polarization.

Keywords: cosmic electrodynamics; extragalactic magnetic fields; radio transient sources; neutron stars; polarimetry; radio pulsars; pulsars
Eclipsing the X-Ray Emitting Region in the Active Galaxy NGC 6814

We report the detection of a rapid occultation event in the nearby Seyfert galaxy NGC 6814, simultaneously captured in a transient light curve and spectral variability. The intensity and hardness ratio curves capture distinct ingress and egress periods that are symmetric in duration. Independent of the selected continuum model, the changes can be simply described by varying the fraction of the central engine that is covered by transiting obscuring gas. Together, the spectral and timing analyses self-consistently reveal the properties of the obscuring gas, its location to be in the broad-line region, and the size of the X-ray source to be ∼ 25 rg. Our results demonstrate that obscuration close to massive black holes can shape their appearance, and can be harnessed to measure the active region that surrounds the event horizon.

Keywords: x-ray active galactic nuclei; x-ray astronomy; astrophysical black holes; supermassive black holes; seyfert galaxies; partial eclipses; eclipses; accretion
Relevant Coma Composition Investigations for the Comet Interceptor Mission

The Comet Interceptor Mission (ESA/JAXA) aims to visit a long-period comet or interstellar object. Its primary science goals are to characterize the object's shape, structure, and the composition of its surface and gas coma. The mission consists of three spacecraft, the primary and two accompanying ones. The focus of this paper is the unique synergetic activities between two mass spectrometers to investigate the chemical composition of the coma, one on the primary spacecraft and another on an accompanying spacecraft. Both can be operated in a complementary fashion, at different locations and at the same time, to sort out spatial from temporal effects. Relevant investigations of the coma composition and chemistry within the technical specifications of the instruments could address several unsolved questions. The Comet Interceptor Mission is posed to be an important mission for advancing our knowledge of comets, especially clues for understanding coma chemistry and composition.

Keywords: comets; comae; chemical abundances; long period comets
Constraints on Metastable Helium in the Atmospheres of WASP-69b and WASP-52b with Ultranarrowband Photometry

Infrared observations of metastable 23S helium absorption with ground- and space-based spectroscopy are rapidly maturing, as this species is a unique probe of exoplanet atmospheres. Specifically, the transit depth in the triplet feature (with vacuum wavelengths near 1083.3 nm) can be used to constrain the temperature and mass-loss rate of an exoplanet's upper atmosphere. Here, we present a new photometric technique to measure metastable 23S helium absorption using an ultranarrowband filter (FWHM 0.635 nm) coupled to a beam-shaping diffuser installed in the Wide-field Infrared Camera on the 200 inch Hale Telescope at Palomar Observatory. We use telluric OH lines and a helium arc lamp to characterize refractive effects through the filter and to confirm our understanding of the filter transmission profile. We benchmark our new technique by observing a transit of WASP-69b and detect an excess absorption of 0.498% ± 0.045% (11.1σ), consistent with previous measurements after considering our bandpass. We then use this method to study the inflated gas giant WASP-52b and place a 95th percentile upper limit on excess absorption in our helium bandpass of 0.47%. Using an atmospheric escape model, we constrain the mass-loss rate for WASP-69b to be ${5.25}_{-0.46}^{+0.65}\times {10}^{-4}\,{M}_{{\rm{J}}}\,{\mathrm{Gyr}}^{-1}$ ( ${3.32}_{-0.56}^{+0.67}\times {10}^{-3}\,{M}_{{\rm{J}}}\,{\mathrm{Gyr}}^{-1}$ ) at 7000 K (12,000 K). Additionally, we set an upper limit on the mass-loss rate of WASP-52b at these temperatures of $2.1\times {10}^{-4}\,{M}_{{\rm{J}}}\,{\mathrm{Gyr}}^{-1}$ ( $2.1\times {10}^{-3}\,{M}_{{\rm{J}}}\,{\mathrm{Gyr}}^{-1}$ ). These results show that ultranarrowband photometry can reliably quantify absorption in the metastable helium feature.

Keywords: exoplanet astronomy; exoplanet atmospheres; planetary atmospheres; transmission spectroscopy; infrared photometry; narrow band photometry
Updated Planetary Mass Constraints of the Young V1298 Tau System Using MAROON-X

The early K-type T-Tauri star, V1298 Tau (V = 10 mag, age ≈ 20-30 Myr) hosts four transiting planets with radii ranging from 4.9 to 9.6 R ⊕. The three inner planets have orbital periods of ≈8-24 days while the outer planet's period is poorly constrained by single transits observed with K2 and the Transiting Exoplanet Survey Satellite (TESS). Planets b, c, and d are proto-sub-Neptunes that may be undergoing significant mass loss. Depending on the stellar activity and planet masses, they are expected to evolve into super-Earths/sub-Neptunes that bound the radius valley. Here we present results of a joint transit and radial velocity (RV) modeling analysis, which includes recently obtained TESS photometry and MAROON-X RV measurements. Assuming circular orbits, we obtain a low-significance (≈2σ) RV detection of planet c, implying a mass of ${19.8}_{-8.9}^{+9.3}\,{M}_{\oplus }$ and a conservative 2σ upper limit of <39 M ⊕. For planets b and d, we derive 2σ upper limits of M b < 159 M ⊕ and M d < 41 M ⊕, respectively. For planet e, plausible discrete periods of P e > 55.4 days are ruled out at the 3σ level while seven solutions with 43.3 < P e/d < 55.4 are consistent with the most probable 46.768131 ± 000076 days solution within 3σ. Adopting the most probable solution yields a 2.6σ RV detection with a mass of 0.66 ± 0.26 M Jup. Comparing the updated mass and radius constraints with planetary evolution and interior structure models shows that planets b, d, and e are consistent with predictions for young gas-rich planets and that planet c is consistent with having a water-rich core with a substantial (~5% by mass) H2 envelope.

Keywords: exoplanet astronomy; exoplanets; mini neptunes; transits; radial velocity; exoplanet systems
A Localized Kinematic Structure Detected in Atomic Carbon Emission Spatially Coincident with a Proposed Protoplanet in the HD 163296 Disk

Over the past 5 yr, studies of the kinematics in protoplanetary disks have led to the discovery of new protoplanet candidates and several structures linked to possible planet-disk interactions. We detect a localized kinematic bipolar structure in the HD 163296 disk present inside the deepest dust gap at 48 au from atomic carbon line emission. HD 163296's stellar jet and molecular winds have been described in detail in the literature; however, the kinematic anomaly in C I emission is not associated with either of them. Further, the velocity of the kinematic structure points indicates a component fast enough to differentiate it from the Keplerian profile of the disk, and its atomic nature hints at a localized UV source strong enough to dissociate CO and launch a C I outflow or a strong polar flow from the upper layers of the disk. By discarding the stellar jet and previously observed molecular winds, we explore different sources for this kinematic feature in C I emission that could be associated with a protoplanet inflow/outflow or disk winds.

Keywords: protoplanetary disks; planet formation; planetary-disk interactions
Properties of an Interplanetary Shock Observed at 0.07 and 0.7 au by Parker Solar Probe and Solar Orbiter

The Parker Solar Probe (PSP) and Solar Orbiter (SolO) missions opened a new observational window in the inner heliosphere, which is finally accessible to direct measurements. On 2022 September 5, a coronal mass ejection (CME)-driven interplanetary (IP) shock was observed as close as 0.07 au by PSP. The CME then reached SolO, which was radially well-aligned at 0.7 au, thus providing us with the opportunity to study the shock properties at different heliocentric distances. We characterize the shock, investigate its typical parameters, and compare its small-scale features at both locations. Using the PSP observations, we investigate how magnetic switchbacks and ion cyclotron waves are processed upon shock crossing. We find that switchbacks preserve their V–B correlation while compressed upon the shock passage, and that the signature of ion cyclotron waves disappears downstream of the shock. By contrast, the SolO observations reveal a very structured shock transition, with a population of shock-accelerated protons of up to about 2 MeV, showing irregularities in the shock downstream, which we correlate with solar wind structures propagating across the shock. At SolO, we also report the presence of low-energy (∼100 eV) electrons scattering due to upstream shocklets. This study elucidates how the local features of IP shocks and their environments can be very different as they propagate through the heliosphere.

Keywords: interplanetary shocks; solar wind; heliosphere
The High-energy Spectrum of the Young Planet Host V1298 Tau

V1298 Tau is a young pre-main-sequence star hosting four known exoplanets that are prime targets for transmission spectroscopy with current-generation instruments. This work pieces together observations from the NICER X-ray telescope, the Space Telescope Imaging Spectrograph and Cosmic Origins Spectrograph instruments aboard Hubble Space Telescope, and empirically informed models to create a panchromatic spectral energy distribution for V1298 Tau spanning 1–105 Å. We describe the methods and assumptions used to assemble the panchromatic spectrum and show that despite this star's brightness, its high-energy spectrum is near the limit of present X-ray and ultraviolet observatories' abilities to characterize. We conclude by using the V1298 Tau spectrum as a benchmark for the activity saturation stage of high-energy radiation from solar-mass stars to compare the lifetime cumulative high-energy irradiation of the V1298 Tau planets to other planets orbiting similarly massive stars.

Keywords: pre-main sequence stars; x-ray astronomy; ultraviolet astronomy; stellar atmospheres; stellar chromospheres; stellar coronae; atmospheric evolution; stellar magnetic fields
ZTF-identified HW Virginis Systems

We present 46 HW Virginis Post-Common Envelope Binary Systems identified by the Zwicky Transient Facility, 26 of which appear to be new discoveries. Through the application of the Box Least-Squares Algorithm to ZTF data, we searched a data set of 17,473 systems for periodicity and phase-folded all of the ZTF lightcurves of the objects at their best period. Through visual analysis of these phase-folded lightcurves, we identified the 46 HW Vir Systems.

Keywords: common envelope binary stars; light curves; light curve classification; eclipsing binary stars; common envelope evolution; interacting binary stars; o subdwarf stars; automated telescopes; optical astronomy; b subdwarf stars; surveys; cataclysmic variable stars
Physical and Chemical Structure of the Disk and Envelope of the Class 0/I Protostar L1527

Submillimeter spectral line and continuum emission from the protoplanetary disks and envelopes of protostars is a powerful probe of their structure, chemistry, and dynamics. Here we present a benchmark study of our modeling code, RadChemT, that for the first time uses a chemical model to reproduce ALMA C18O (2-1), and CARMA 12CO (1-0) and N2H+ (1-0) observations of L1527; this allows us to distinguish the disk, the infalling envelope, and outflow of this Class 0/I protostar. RadChemT combines dynamics, radiative transfer, gas chemistry, and gas-grain reactions to generate models that can be directly compared with observations for individual protostars. Rather than individually fit abundances to a large number of free parameters, we aim to best match the spectral line maps by (i) adopting a physical model based on density structure and luminosity derived primarily from previous work that fit spectral energy distribution and 2D imaging data, updating it to include a narrow jet detected in CARMA and ALMA data near (≤75 au) the protostar, and then (ii) computing the resulting astrochemical abundances for 292 chemical species. Our model reproduces the C18O and N2H+ line strengths within a factor of 3.0; this is encouraging considering the pronounced abundance variation (factor >103) between the outflow shell and CO snowline region near the midplane. Further, our modeling confirms suggestions regarding the anticorrelation between N2H+ and the CO snowline between 400 au and 2000 au from the central star. Our modeling tools represent a new and powerful capability with which to exploit the richness of spectral line imaging provided by modern submillimeter interferometers.

Keywords: protostars; radiative transfer; astrochemistry; spectral line identification; star formation; molecular physics
ZFIRE: Measuring Electron Density with [O II] as a Function of Environment at z = 1.62

The global star formation rates (SFR) of galaxies at fixed stellar masses increase with redshift and are known to vary with environment up to z ∼ 2. We explore here whether the changes in the SFRs also apply to the electron densities of the interstellar medium by measuring the [O II] (λ 3726, λ 3729) ratio for cluster and field galaxies at z ∼ 2. We measure a median electron density of ne = 366 ± 84 cm-3 for six galaxies (with 1σ scatter = 163 cm-3) in the Ultra-Deep Survey (UDS) protocluster at z = 1.62. We find that the median electron density of galaxies in the UDS protocluster environment is three times higher compared to the median electron density of field galaxies (ne = 113 ± 63 cm03 and 1 &sigma scatter = 79 cm-3) at comparable redshifts, stellar mass, and SFR. However, we note that a sample of six protocluster galaxies is insufficient to reliably measure the electron density in the average protocluster environment at z ∼ 2. We conclude that the electron density increases with redshift in both cluster and field environments up to z ∼ 2 (ne = 30 ± 1 cm-3 for z ∼ 0 to ne = 254 ± 76 cm-3 for z ∼ 1.5). We find tentative evidence (∼2.6σ) for a possible dependence of electron density on environment, but the results require confirmation with larger sample sizes.

Keywords: galaxy evolution; high-redshift galaxies; emission line galaxies; high-redshift galaxy clusters