adsabs/SciX_UAT_keywords huggingface dataset:
Dynamical Architecture of the HD 107148 Planetary System

We present an independent Doppler validation and dynamical orbital analysis of the two-planet system HD 107148, which was recently announced in Rosenthal et al. Our detailed analyses are based on literature HIRES data and newly obtained HARPS and CARMENES radial-velocity (RV) measurements as part of our survey in search for additional planets around single-planet systems. We perform a periodogram analysis of the available HIRES and HARPS precise RVs and stellar activity indicators. We do not find any apparent correlation between the RV measurements and the stellar activity indicators, thus linking the two strong periodicities to a moderately compact multiplanet system. We carry out orbital fitting analysis by testing various one- and two-planet orbital configurations and studying the posterior probability distribution of the fitted parameters. Our results solidify the existence of a Saturn-mass planet (HD 107148b, discovered first) with a period of P b ~ 77.2 days and a second, eccentric (e c ~ 0.4), Neptune-mass exoplanet (HD 107148c) with an orbital period of P c ~ 18.3 days. Finally, we investigate the two-planet system's long-term stability and overall orbital dynamics with the posterior distribution of our preferred orbital configuration. Our N-body stability simulations show that the system is long-term stable and exhibits large secular osculations in eccentricity but in no particular mean motion resonance configuration. The HD 107148 system, consisting of a solar-type main-sequence star with two giant planets in a rare configuration, features a common proper-motion white dwarf companion and is therefore a valuable target for understanding the formation and evolution of planetary systems.

Keywords: exoplanet astronomy; exoplanet detection methods; exoplanet dynamics; radial velocity; exoplanet systems
Homogenizing SOHO/EIT and SDO/AIA 171 Å Images: A Deep-learning Approach

Extreme-ultraviolet (EUV) images of the Sun are becoming an integral part of space weather prediction tasks. However, having different surveys requires the development of instrument-specific prediction algorithms. As an alternative, it is possible to combine multiple surveys to create a homogeneous data set. In this study, we utilize the temporal overlap of Solar and Heliospheric Observatory Extreme ultraviolet Imaging Telescope and Solar Dynamics Observatory Atmospheric Imaging Assembly 171 Å surveys to train an ensemble of deep-learning models for creating a single homogeneous survey of EUV images for two solar cycles. Prior applications of deep learning have focused on validating the homogeneity of the output while overlooking the systematic estimation of uncertainty. We use an approach called "approximate Bayesian ensembling" to generate an ensemble of models whose uncertainty mimics that of a fully Bayesian neural network at a fraction of the cost. We find that ensemble uncertainty goes down as the training set size increases. Additionally, we show that the model ensemble adds immense value to the prediction by showing higher uncertainty in test data that are not well represented in the training data.

Keywords: solar corona; convolutional neural networks; calibration; solar atmosphere; solar extreme ultraviolet emission
Deep Observations of CO and Free-Free Emission in Ultraluminous Infrared QSO IRAS F07599+6508

Infrared quasi-stellar objects (IR QSOs) are a rare subpopulation selected from ultraluminous infrared galaxies (ULIRGs) and have been regarded as promising candidates of ULIRG-to-optical QSO transition objects. Here we present NOEMA observations of the CO (1-0) line and 3 mm continuum emission in IR QSO IRAS F07599+6508 at z = 0.1486, which has many properties in common with Mrk 231. The CO emission is found to be resolved with a major axis of ∼6.1 kpc that is larger than the size of ∼4.0 kpc derived for 3 mm continuum. We identify two faint CO features located at a projected distance of ∼11.4 and 19.1 kpc from the galaxy nucleus, both of which are found to have counterparts in the optical and radio bands and may have a merger origin. A systematic velocity gradient is found in the CO main component, suggesting that the bulk of molecular gas is likely rotationally supported. Based on the radio-to-millimeter spectral energy distribution and IR data, we estimate that about 30% of the flux at 3 mm arises from free-free emission and infer a free-free-derived star formation rate of 77 M⊙ yr-1, close to the IR estimate corrected for the AGN contribution. We find a high-velocity CO emission feature at the velocity range of about -1300 to -2000 km s-1. Additional deep CO observations are needed to confirm the presence of a possible very high velocity CO extension of the OH outflow in this IR QSO.

Keywords: starburst galaxies; galaxy mergers; agn host galaxies; interstellar molecules; galaxy evolution
ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Molecular Jets and Episodic Accretion in Protostars

Protostellar outflows and jets are almost ubiquitous characteristics during the mass accretion phase and encode the history of stellar accretion, complex organic molecule (COM) formation, and planet formation. Episodic jets are likely connected to episodic accretion through the disk. Despite the importance, studies on episodic accretion and ejection links have not been done yet in a systematic fashion using high-sensitivity and high-resolution observations. To explore episodic accretion mechanisms and the chronologies of episodic events, we investigated 39 fields containing protostars with Atacama Large Millimeter/submillimeter Array observations of CO, SiO, and 1.3 mm continuum emission. We detected SiO emission in 19 fields, where 17 sources are driving molecular jets. Jet velocities, mass-loss rates, mass accretion rates, and periods of accretion events appear to have some dependence on the driving forces of the jet (e.g., bolometric luminosity, envelope mass). Next, velocities and mass-loss rates appear to be somewhat correlated with the surrounding envelope mass, suggesting that the presence of high mass around protostars increases the ejection–accretion activity. We determine mean periods of ejection events of 20–175 yr for our sample, which could be associated with perturbation zones of ∼2‑25 au extent around the protostars. In addition, mean ejection periods show an apparent anticorrelation with the envelope mass, where high accretion rates may trigger more frequent ejection events. The observed periods of outburst/ejection are much shorter than the freezeout timescale of the simplest COMs like CH3OH, suggesting that episodic events could affect the ice–gas balance inside and around the snowline.

Keywords: star formation; protostars; stellar jets; stellar winds; stellar accretion; submillimeter astronomy
TESS Observations of the Hot Jupiter Exoplanet XO-6b: No Evidence of Transit Timing Variations

From previous ground-based observations, the hot Jupiter exoplanet XO-6b was reported to exhibit apparently periodic transit timing variations (TTVs), with a semi-amplitude of 14 minutes and a period of about 450 days. These variations were interpreted as being due to a resonant perturbation between XO-6b and a hitherto unknown low-mass planet orbiting the same star. To understand this enigmatic planetary system better, we analyzed three sectors of data, spanning over seven months, from the Transiting Exoplanet Survey Satellite (TESS), which produces high-quality light curves that are well suited to characterizing exoplanets and searching for TTVs. Here we present an updated orbital period of 3.7649893 ± 0.0000037 days and a transit epoch of 2456652.7157 ± 0.0022 BJDTDB. The planetary parameters we report, while consistent with their discovery values, have greatly improved precision. Notably, we find no evidence for TTVs: we can rule out TTVs ≳2.5 minutes at the 3σ level. Therefore, the TESS data have sufficient precision and time baseline to readily reveal the previously reported TTVs of approximately 10 minutes. Our findings highlight the capability of TESS for robust follow-up, and confirm that TTVs are rarely seen in hot Jupiters, unlike is the case with small planets.

Keywords: exoplanet dynamics; hot jupiters; exoplanets; photometry; transit timing variation method
The Effects of Including Farside Observations on In Situ Predictions of Heliospheric Models

A significant challenge facing heliospheric models is the lack of full Sun observational coverage. The lack of information about the farside photospheric magnetic field necessitates the use of various techniques to approximate the structure and appearance of this field. However, a recently developed technique that uses He II 304 Å emission observed by the Solar Terrestrial Relations Observatory (STEREO) enables developing a magnetic flux proxy by imaging of active regions on the far side of the Sun. Incorporating information about these active regions on the far side of the Sun may have the potential to drastically improve heliospheric models. In this work, we run multiple heliospheric models with and without farside information obtained from STEREO observations of He II 304 Å emission and compare the predicted in situ measurements from the models with real in situ data from STEREO and Earth. We find that although there are noticeable quantitative differences between the in situ predictions from the two models, they are dwarfed by the overall disagreement between the heliospheric model and the actual in situ data. Nevertheless, our results indicate that active regions that significantly change the ratio of open-to-closed and open-to-total flux create the biggest change in the predicted in situ measurements.

Keywords: heliosphere; solar wind
A Timing Study of MAXI J1820+070 Based on Swift/XRT and NICER Monitoring in 2018/19

We present a detailed timing analysis of the bright black hole X-ray binary MAXI J1820+070 (ASASSN-18ey), during its first detected outburst lasting from 2018 March until 2019 October based on Swift/XRT window timing mode observations, corresponding UVOT data and NICER observations. The light curves clearly show four outbursts, with the source remaining in the hard state during its first outburst, while the rise of the second outburst corresponds with the transition to the soft state. A similar double outburst of GX339-4 has been observed in 2004. Here it is followed by two hard-state only outbursts. In many observations the power density spectra showed type-C quasi-periodic oscillations (QPOs) with characteristic frequencies below 1 Hz, which suggests that the source stayed in a state of low effective accretion for large parts of its outburst. The absence of other types of QPOs hinders a precise determination of the state transitions, but from combining NICER and Swift/XRT data, we find that MAXI J1820+070 went from the hard-intermediate to the soft state in less than one day. The covariance ratios derived from NICER data show an increase toward lower energies, which indicate that the source should make a transition to the soft state. This transition finally took place, after MAXI J1820+070 stayed in the hard state at rather constant luminosity for about 116 days. The steepness of the increase of the covariance ratios is not correlated with the amount of rms variability and it does not show a monotonic evolution along the outburst.

Keywords: stellar mass black holes; low-mass x-ray binary stars; close binary stars; transient sources
AGNs on the Move: A Search for Off-nuclear AGNs from Recoiling Supermassive Black Holes and Ongoing Galaxy Mergers with the Zwicky Transient Facility

A supermassive black hole (SMBH) ejected from the potential well of its host galaxy via gravitational wave recoil carries important information about the mass ratio and spin alignment of the pre-merger SMBH binary. Such a recoiling SMBH may be detectable as an active galactic nucleus (AGN) broad-line region offset by up to 10 kpc from a disturbed host galaxy. We describe a novel methodology using forward modeling with The Tractor to search for such offset AGNs in a sample of 5493 optically variable AGNs detected with the Zwicky Transient Facility (ZTF). We present the discovery of nine AGNs that may be spatially offset from their host galaxies and are candidates for recoiling SMBHs. Five of these offset AGNs exhibit double-peaked broad Balmer lines, which may have arisen from unobscured accretion disk emission, and four show radio emission indicative of a relativistic jet. The fraction of double-peaked emitters in our spatially offset AGN sample is significantly larger than the 16% double-peaked emitter fraction observed for ZTF AGNs overall. In our sample of variable AGNs we also identified 52 merging galaxies, including a new spectroscopically confirmed dual AGN. Finally, we detected the dramatic rebrightening of SDSS 1133, a previously discovered variable object and recoiling SMBH candidate, in ZTF. The flare was accompanied by the reemergence of strong P Cygni line features, indicating that SDSS 1133 may be an outbursting luminous blue variable star.

Keywords: active galactic nuclei; galaxy mergers; supermassive black holes
Magnetic Fields in the Southern Coalsack and Beyond

Starlight polarimetry, when combined with accurate distance measurements, allows for exploration of the three-dimensional structure of local magnetic fields in great detail. We present optical polarimetric observations of stars in and close to the Southern Coalsack, taken from the Interstellar Polarization Survey. Located in five fields of view approximately 0.°3 × 0.°3 in size, these data represent the highest density of optical polarimetric observations in the Southern Coalsack to date. Using these data, combined with accurate distances and extinctions based on Gaia data, we are able to characterize the magnetic field of the Coalsack and disentangle contributions to the polarization caused by the Southern Coalsack and a background structure. For the Southern Coalsack, we find an average magnetic field orientation of θ ∼ 75° with respect to the Galactic north pole and an average plane-of-sky magnetic field strength of approximately B POS = 10 μG, using the Davis–Chandrasekhar–Fermi method. These values are in agreement with some earlier estimates of the Coalsack's magnetic field. In order to study the distant structure, we introduce a simple method to separate and isolate the polarization of distant stars from foreground contribution. For the distant structure, which we estimate to be located at a distance of approximately 1.3–1.5 kpc, we find an average magnetic field orientation of θ ∼ 100° and estimate a field strength of B POS ∼ 10 μG, although this will remain highly uncertain until the precise nature of the distant structure can be uncovered.

Keywords: interstellar magnetic fields; interstellar medium; dark interstellar clouds; polarimetry; starlight polarization; milky way magnetic fields
The Circumgalactic Medium of Extreme Emission Line Galaxies at z 2: Resolved Spectroscopy and Radiative Transfer Modeling of Spatially Extended Lyα Emission in the KBSS-KCWI Survey

The resonantly scattered Lyα line illuminates the extended halos of neutral hydrogen in the circumgalactic medium of galaxies. We present integral field Keck Cosmic Web Imager observations of double-peaked, spatially extended Lyα emission in 12 relatively low-mass (M ⋆ ~ 109 M⊙) z ~ 2 galaxies characterized by extreme nebular emission lines. Using individual spaxels and small bins as well as radially binned profiles of larger regions, we find that for most objects in the sample the Lyα blue-to-red peak ratio increases, the peak separation decreases, and the fraction of flux emerging at line center increases with radius. We use new radiative transfer simulations to model each galaxy with a clumpy, multiphase outflow with radially varying outflow velocity, and self-consistently apply the same velocity model to the low-ionization interstellar absorption lines. These models reproduce the trends of peak ratio, peak separation, and trough depth with radius, and broadly reconcile outflow velocities inferred from Lyα and absorption lines. The galaxies in our sample are well-described by a model in which neutral, outflowing clumps are embedded in a hotter, more highly ionized inter-clump medium (ICM), whose residual neutral content produces absorption at the systemic redshift. The peak ratio, peak separation, and trough flux fraction are primarily governed by the line-of-sight component of the outflow velocity, the H I column density, and the residual neutral density in the ICM respectively. The azimuthal asymmetries in the line profile further suggest nonradial gas motions at large radii and variations in the H I column density in the outer halos. *Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W.M. Keck Foundation.

Keywords: galaxy evolution; high-redshift galaxies; circumgalactic medium; galaxy spectroscopy; radiative transfer simulations
Stability and Detectability of Exomoons Orbiting HIP 41378 f, a Temperate Jovian Planet with an Anomalously Low Apparent Density

Moons orbiting exoplanets ("exomoons") may hold clues about planet formation, migration, and habitability. In this work, we investigate the plausibility of exomoons orbiting the temperate (T eq = 294 K) giant (R = 9.2 R ⊕) planet HIP 41378 f, which has been shown to have a low apparent bulk density of 0.09 g cm-3 and a flat near-infrared transmission spectrum, hinting that it may possess circumplanetary rings. Given this planet's long orbital period (P ≈ 1.5 yr), it has been suggested that it may also host a large exomoon. Here, we analyze the orbital stability of a hypothetical exomoon with a satellite-to-planet mass ratio of 0.0123 orbiting HIP 41378 f. Combining a new software package, astroQTpy, with REBOUND and EqTide, we conduct a series of N-body and tidal migration simulations, demonstrating that satellites up to this size are largely stable against dynamical escape and collisions. We simulate the expected transit signal from this hypothetical exomoon and show that current transit observations likely cannot constrain the presence of exomoons orbiting HIP 41378 f, though future observations may be capable of detecting exomoons in other systems. Finally, we model the combined transmission spectrum of HIP 41378 f and a hypothetical moon with a low-metallicity atmosphere and show that the total effective spectrum would be contaminated at the ~10 ppm level. Our work not only demonstrates the feasibility of exomoons orbiting HIP 41378 f but also shows that large exomoons may be a source of uncertainty in future high-precision measurements of exoplanet systems.

Keywords: exoplanet astronomy; exoplanet dynamics; exoplanet systems; exoplanet tides; natural satellites (extrasolar); transits; transmission spectroscopy
Interstellar Detection of O-protonated Carbonyl Sulfide, HOCS+

We present the first detection in space of O-protonated carbonyl sulfide (HOCS+), in the midst of an ultradeep molecular line survey toward the G+0.693-0.027 molecular cloud. From the observation of all K a = 0 transitions ranging from J lo = 2 to J lo = 13 of HOCS+ covered by our survey, we derive a column density of N = (9 ± 2) × 1012 cm‑2, translating into a fractional abundance relative to H2 of ∼7 × 10‑11. Conversely, the S-protonated HSCO+ isomer remains undetected, and we derive an upper limit to its abundance with respect to H2 of ≤3 × 10‑11, a factor of ≥2.3 less abundant than HOCS+. We obtain an HOCS+/OCS ratio of ∼2.5 × 10‑3, in good agreement with the prediction of astrochemical models. These models show that one of the main chemical routes to the interstellar formation of HOCS+ is likely the protonation of OCS, which appears to be more efficient at the oxygen end. Also, we find that high values of cosmic-ray ionization rates (10‑15–10‑14 s‑1) are needed to reproduce the observed abundance of HOCS+. In addition, we compare the O/S ratio across different interstellar environments. G+0.693-0.027 appears as the source with the lowest O/S ratio. We find an HOCO+/HOCS+ ratio of ∼31, in accordance with other O/S molecular pairs detected toward this region and also close to the O/S solar value (∼37). This fact indicates that S is not significantly depleted within this cloud due to the action of large-scale shocks, unlike in other sources where S-bearing species remain trapped on icy dust grains.

Keywords: interstellar molecules; astrochemistry; spectral line identification; galactic center; interstellar clouds
Abundances of Iron-peak Elements in the B8 Mn Star HD 110073

The synthesis of spectral intervals in the optical range allows the determination of LTE abundances of several iron-peak elements for the chemically peculiar B8 Mn star HD 110073. Titanium, chromium and manganese are found to be overabundant by factors of 19, 4 and 250 times their respective solar abundances. Iron and nickel are deficient by factors of 0.25 and 0.10. Weak lines of Cr II formed deep in the atmosphere yield lower chromium abundances than strong lines do by a factor of 2. This supports that chromium is probably stratified vertically in the atmosphere of HD 110073. Several weak flat-bottomed lines which could be caused by vertical stratification of the abundances are present throughout the spectra. The new abundance determinations differ from previous determinations partly because the atomic data have changed. A non-uniform distribution of the elements over the surface of HD 110073 could also account for variation of the lines with time.

Keywords: chemically peculiar stars; mercury-manganese stars
The Coevolution of Galaxies and the Cool Circumgalactic Medium Probed with the SDSS and DESI Legacy Imaging Surveys

We study the evolution of galaxies and the circumgalactic medium (CGM) through cosmic time by correlating ∼50,000 Mg II absorbers, tracers of cool gas (∼104 K), detected in the Sloan Digital Sky Survey quasar spectra with galaxies detected in the DESI Legacy Imaging Surveys. By doing so, we extract the properties of galaxies associated with absorbers from redshift 0.4 to 1.3 with effectively ∼15,000 pairs and explore the covering fraction of Mg II absorbers as a function of galaxy type, stellar mass, impact parameter, and redshift. We find that the gas covering fraction increases with stellar mass of galaxies by $\sim {M}_{* }^{0.4}$ . However, after we normalize the impact parameter by the virial radius of dark matter halos, the gas profiles around galaxies with masses ranging from 109 to ${10}^{11}\,{M}_{\odot }$ become weakly dependent on stellar mass. In addition, the gas distribution depends on galaxy type: the covering fraction within $0.3\,{r}_{\mathrm{vir}}$ around star-forming galaxies is 2-4 times higher than that around passive galaxies at all redshifts. We find that the covering fraction of strong absorbers ( ${W}_{\lambda 2796}\gt 1\,\mathring{\rm A} $ ) around both types of galaxies evolves significantly with redshift, similarly to the evolution of star formation rate (SFR) of galaxies, while such an evolution is not detected for weak absorbers ( ${W}_{\lambda 2796}\lt 1\,\mathring{\rm A} $ ). We quantify the H I mass traced by strong absorbers and find that the gas mass around galaxies evolves consistently with the SFR of galaxies. This result suggests that the properties of galaxies and their CGM coevolve through cosmic time. Finally, we discuss the origins of strong absorbers around passive galaxies and argue that its redshift evolution may trace the star formation activity of satellite galaxies.

Keywords: galaxy evolution; circumgalactic medium; quasar absorption line spectroscopy