adsabs/SciX_UAT_keywords huggingface dataset:
Hidden Companions to Intermediate-mass Stars. XI. Uncovering a 0.7 M ⊙, 2.3 au Companion in the Astrometric Binary HIP 111200 = 58 Aquarii

We report on the direct VLTI/GRAVITY interferometric detection of a close companion in the nearby Hipparcos astrometric binary 58 Aquarii with a K band flux ratio of 5.0% at a projected separation 32 mas ↔ 2.3 au. Through isochrone fitting we find that the primary is a 1.4 Gyr old, 1.68 M ⊙ late A-type star and the companion is a 0.72 M ⊙ K-type star. The estimated cooling age of 900 Myr for the wide (9940 au), 0.70 M ⊙ white dwarf (WD) companion to the system is consistent with a progenitor star of 2.9 M ⊙ assuming single star evolution. The survival of the triple system at such large separation suggests a low kick in the formation of the WD or alternatively that it has since migrated outwards through three-body interaction. *Based on observations collected at the European Southern Observatory, Chile, Program ID 111.24UP.001.

Keywords: a stars; optical interferometry; white dwarf stars; multiple stars; astrometric binary stars
On the Origin of Observed Cosmic-Ray Spectrum Below 100 TV

Recent precise measurements of primary and secondary cosmic-ray (CR) species in the teravolt rigidity domain have unveiled a bump in their spectra, located between 0.5 and 50 TV. We argue that a local shock may generate such a bump by increasing the rigidity of the preexisting CRs below 50 TV by a mere factor of ~1.5. Reaccelerated particles below ~0.5 TV are convected with the interstellar medium flow and do not reach the Sun, thus creating the bump. This single universal process is responsible for the observed spectra of all CR species in the rigidity range below 100 TV. We propose that one viable shock candidate is the Epsilon Eridani star at 3.2 pc from the Sun, which is well aligned with the direction of the local magnetic field. Other shocks, such as old supernova shells, may produce a similar effect. We provide a simple formula, Equation (9), that reproduces the spectra of all CR species with only two nonadjustable shock parameters, uniquely derived from the proton data. We show how our formalism predicts helium and carbon spectra and the B/C ratio.

Keywords: galactic cosmic rays; secondary cosmic rays; astrosphere interstellar medium interactions; interstellar medium; shocks; stellar bow shocks
On the Probability of the Extremely Lensed z = 6.2 Earendel Source Being a Population III Star

The recent discovery of the extremely lensed Earendel object at z = 6.2 is remarkable in that it is likely a single star or stellar multiple, observed within the first billion years of cosmic history. Depending on its mass, which is still uncertain but will soon be more tightly constrained with the James Webb Space Telescope, the Earendel star might even be a member of the first generation of stars, the so-called Population III (Pop III). By combining results from detailed cosmological simulations of the assembly of the first galaxies, including the enrichment of the pristine gas with heavy chemical elements, with assumptions on key stellar parameters, we quantify the probability that Earendel indeed has a Pop III origin. We find that this probability is nonnegligible throughout the mass range inferred for Earendel, specifically ranging from a few percent at the lower-mass end to near unity for some Pop III initial mass function (IMF) models toward the high-mass end of the allowed range. For models that extend the metal-enriched IMF to 500 M ⊙, the likelihood of Earendel being a Pop III star stays at the few to 10% level. We discuss the implications of such a discovery for the overall endeavor to probe the hitherto so elusive first stars in the universe.

Keywords: early universe; population iii stars; reionization; population ii stars; gravitational lensing
Extreme Rarefaction of Solar Wind: A Study on Origin and Characteristics Using Ulysses Observations

From the Ulysses observation of the solar wind between the heliocentric distance r h of ~1.0 and ~5.4 au during 1990-2009, we identified 53 intervals when the solar wind exhibited extreme rarefaction, ~2 orders of magnitude decreases in the solar wind proton density N p from their ambient values. These extremely low-density solar wind (ELDSW) events, characterized by an average (median) N p of ~0.28 ± 0.09 (~0.30) cm-3, ram pressure of ~0.07 ± 0.04 (~0.07 nPa) and mass flux of ~166 ± 84 (~159) 10-22 kg cm-2 s-1 all normalized to 1 au, have an average (median) duration of ~6.0 ± 3.5 days (~5.5 days), and radial extent of ~1.9 ± 1.1 au (~1.9 au). A clear hemispheric asymmetry is noted in their solar/interplanetary origin, with 70% being identified in the south hemisphere, and 30% in the north hemisphere of the heliosphere. About 23% of the events were encountered between r h of 2.25 and 4 au, and 77% at r h > 4 au, indicating that these are not intrinsic properties of the Sun/solar corona but are created by the evolution of the solar wind with increasing radial distance from the Sun. The majority (49%) of the events occurred during magnetic clouds, 34% in solar wind high-speed stream (HSS) tails, 11% during the proper HSSs, and 6% during interplanetary sheaths. The identification of ELDSWs will have important consequences for their interaction with the magnetospheres of Jupiter and Saturn.

Keywords: solar wind; interplanetary medium; interplanetary magnetic fields; fast solar wind; solar coronal mass ejections; corotating streams
Search for 10–1000 GeV Neutrinos from Gamma-Ray Bursts with IceCube

We present the results of a search for 10–1000 GeV neutrinos from 2268 gamma-ray bursts (GRBs) over 8 yr of IceCube-DeepCore data. This work probes burst physics below the photosphere where electromagnetic radiation cannot escape. Neutrinos of tens of giga electronvolts are predicted in sub-photospheric collision of free-streaming neutrons with bulk-jet protons. In a first analysis, we searched for the most significant neutrino-GRB coincidence using six overlapping time windows centered on the prompt phase of each GRB. In a second analysis, we conducted a search for a group of GRBs, each individually too weak to be detectable, but potentially significant when combined. No evidence of neutrino emission is found for either analysis. The most significant neutrino coincidence is for Fermi-GBM GRB bn 140807500, with a p-value of 0.097 corrected for all trials. The binomial test used to search for a group of GRBs had a p-value of 0.65 after all trial corrections. The binomial test found a group consisting only of GRB bn 140807500 and no additional GRBs. The neutrino limits of this work complement those obtained by IceCube at tera electronvolt to peta electronvolt energies. We compare our findings for the large set of GRBs as well as GRB 221009A to the sub-photospheric neutron-proton collision model and find that GRB 221009A provides the most constraining limit on baryon loading. For a jet Lorentz factor of 300 (800), the baryon loading on GRB 221009A is lower than 3.85 (2.13) at a 90% confidence level.

Keywords: cosmological neutrinos; gamma-ray bursts
TESS Science Processing Operations Center FFI Target List Products

We report the delivery to the Mikulski Archive for Space Telescopes of target pixel and light curve files for up to 160,000 targets selected from full-frame images (FFI) for each TESS Northern hemisphere observing sector. The data include calibrated target pixels, simple aperture photometry flux time series, and presearch data conditioning corrected flux time series. These data provide TESS users with high quality, uniform pipeline products for a selection of FFI targets, that would otherwise not be readily available. Additionally, we deliver cotrending basis vectors derived from the FFI targets to allow users to perform their own systematic error corrections. The selected targets include all 2 minute targets and additional targets selected from the TESS Input Catalog with a maximum of 10,000 targets per sector on each of the sixteen TESS CCDs. The data products are in the same format as the project-delivered files for the TESS 2 minute targets.

Keywords: catalogs; ccd photometry; stellar photometry
Primordial Black Holes Formation and Secondary Gravitational Waves in Nonminimal Derivative Coupling Inflation

We study the possibility of the primordial black holes (PBHs) formation with the aim of finding a considerable fraction of dark matter (DM), using the gravitationally enhanced friction mechanism which arises from a nonminimal derivative coupling between the scalar field and the gravity. Assuming the nonminimal coupling parameter as a special function of the scalar field and considering the potential of natural inflation, we find three parameter sets that produce a period of ultra slow-roll inflation. This leads to sufficiently large enhancement in the curvature power spectra to form PBHs. We show that under the gravitationally enhanced friction mechanism, PBHs with a mass around ${ \mathcal O }\left({10}^{-12}\right){M}_{\odot }$ can constitute around 96% of the total DM and so this class of PBHs can be taken as a great candidate for DM. We further study the secondary gravitational waves (GWs) in our setting and show that our model predicts the peak of the present fractional energy density as ΩGW0 ~ 10-8 at different frequencies for all the three parameter sets. This value lies well inside the sensitivity region of some GWs detectors at some frequencies, and therefore the observational compatibility of our model can be appraised by the data from these detectors.

Keywords: cosmic inflation; primordial black holes; gravitational waves
Optical Observations of the Nearby Type Ia Supernova 2021hpr

We present the optical photometric and spectroscopic observations of the nearby Type Ia supernova (SN) 2021hpr. The observations covered the phase of -14.37 to +63.68 days relative to its maximum luminosity in the B band. The evolution of multiband light/color curves of SN 2021hpr is similar to that of normal Type Ia supernovae (SNe Ia) with the exception of some phases, especially a plateau phase that appeared in the V - R color curve before peak luminosity, which resembles that of SN 2017cbv. The first spectrum we observed at t ~ -14.4 days shows a higher velocity for the Si II λ6355 feature (~21,000 km s-1) than that of other normal velocity (NV) SNe Ia at the same phase. Based on the Si II λ6355 velocity of ~12,420 km s-1 around maximum light, we deduce that SN 2021hpr is a transitional object between high velocity (HV) and NV SNe Ia. Meanwhile, the Si II λ6355 feature shows a high velocity gradient (HVG) of about 800 km s-1 day-1 from roughly -14.37 to -4.31 days relative to the B-band maximum, which indicates that SN 2021hpr can also be classified as an HVG SN Ia. Despite SN 2021hpr having a higher velocity for the Si II λ6355 and Ca II near-IR (NIR) triplet features in its spectra, its evolution is similar to that of SN 2011fe. Including SN 2021hpr, there have been six supernovae observed in the host galaxy NGC 3147; the supernovae explosion rate in the last 50 yr is slightly higher for SNe Ia, while for SNe Ibc and SNe II it is lower than expected rate from the radio data. Inspecting the spectra, we find that SN 2021hpr has a metal-rich (12 + log(O/H) ≈ 8.648) circumstellar environment, where HV SNe tend to reside. Based on the decline rate of SN 2021hpr in the B band, we determine the distance modulus of the host galaxy NGC 3147 using the Phillips relation to be 33.46 ± 0.21 mag, which is close to that found by previous works.

Keywords: supernovae; galaxies; type ia supernovae
Equalizing the Pixel Response of the Imaging Photoelectric Polarimeter Onboard the IXPE Mission

The Gas Pixel Detector is a gas detector, sensitive to the polarization of X-rays, currently flying onboard the Imaging X-ray Polarimetry Explorer (IXPE)-the first observatory dedicated to X-ray polarimetry. It detects X-rays and their polarization by imaging the ionization tracks generated by photoelectrons absorbed in the sensitive volume, and then reconstructing the initial direction of the photoelectrons. The primary ionization charge is multiplied and ultimately collected on a finely pixellated ASIC specifically developed for X-ray polarimetry. The signal of individual pixels is processed independently and gain variations can be substantial, of the order of 20%. Such variations need to be equalized to correctly reconstruct the track shape, and therefore its polarization direction. The method to do such equalization is presented here and is based on the comparison between the mean charge of a pixel with respect to the other pixels for equivalent events. The method is shown to finely equalize the response of the detectors onboard IXPE, allowing a better track reconstruction and energy resolution, and can in principle be applied to any imaging detector based on tracks.

Keywords: polarimeters; polarimetry; x-ray detectors; astronomical detectors; x-ray telescopes; x-ray observatories; calibration; x-ray astronomy
Resolving the Periods of the Asynchronous Polar 1RXS J083842.1–282723

1RXS J083842.1‑282723 is a nearly synchronous magnetic cataclysmic variable with a simple X-ray light curve. While its orbital period was fairly well established at P orb = 98.4 minutes from optical spectroscopy, indirect estimates of P spin/P orb ranged from 0.90 to 0.96 because the short X-ray light curves could not determine the beat period to a factor of 2. We analyze a recent 50 days TESS observation, and ground-based optical time-series photometry spanning 9 yr, that together measure precise beat, orbit, and spin periods and enable the X-ray and optical modulations to be phase aligned. Although the X-ray light curves do not distinguish between a beat period of 16.11 or 32.22 hr, all of the optical evidence favors the longer value, with complete pole switching of accretion every half beat cycle. This would require P spin/P orb = 0.952. Long-term optical monitoring also shows a decline in accretion rate, and a change in the beat-folded light curve. It would be useful to obtain a new X-ray/optical observation of at least 32 hr duration to examine any associated change in accretion structure, and to confirm the spin and beat periods.

Keywords: cataclysmic variable stars; dq herculis stars; am herculis stars
The Art of Measuring Physical Parameters in Galaxies: A Critical Assessment of Spectral Energy Distribution Fitting Techniques

The study of galaxy evolution hinges on our ability to interpret multiwavelength galaxy observations in terms of their physical properties. To do this, we rely on spectral energy distribution (SED) models, which allow us to infer physical parameters from spectrophotometric data. In recent years, thanks to wide and deep multiwave band galaxy surveys, the volume of high-quality data have significantly increased. Alongside the increased data, algorithms performing SED fitting have improved, including better modeling prescriptions, newer templates, and more extensive sampling in wavelength space. We present a comprehensive analysis of different SED-fitting codes including their methods and output with the aim of measuring the uncertainties caused by the modeling assumptions. We apply 14 of the most commonly used SED-fitting codes on samples from the CANDELS photometric catalogs at z ~ 1 and z ~ 3. We find agreement on the stellar mass, while we observe some discrepancies in the star formation rate (SFR) and dust-attenuation results. To explore the differences and biases among the codes, we explore the impact of the various modeling assumptions as they are set in the codes (e.g., star formation histories, nebular, dust and active galactic nucleus models) on the derived stellar masses, SFRs, and A V values. We then assess the difference among the codes on the SFR-stellar mass relation and we measure the contribution to the uncertainties by the modeling choices (i.e., the modeling uncertainties) in stellar mass (~0.1 dex), SFR (~0.3 dex), and dust attenuation (~0.3 mag). Finally, we present some resources summarizing best practices in SED fitting.

Keywords: extragalactic astronomy; spectral energy distribution; galaxies
Accurate Infrared Line Lists for 20 Isotopologues of CS2 at Room Temperature

To facilitate atmospheric and spectroscopic studies of carbon disulfide, or CS2, in both planetary and exoplanetary atmospheres, we adopt the "Best Theory + Reliable High-resolution Experiment" algorithm to generate semiempirical IR line lists for the 20 most abundant CS2 isotopologues, denoted as Ames-296K. The IR lists are computed using the Ames-1 potential energy surface, refined using the experimental transition set and an ab initio dipole moment surface fitted from CCSD(T)/aug-cc-pV(T/Q/5+d)Z dipoles extrapolated to a one-particle basis set limit. The IR lists cover the range of 0–10,000 cm‑1, with an S 296K cutoff at 10‑31 cm‑1/molecule·cm‑2 (abundance included). A "natural" IR line list at 296 K includes about 10 million lines of the 20 isotopologues, with their intensities scaled by the corresponding abundances. The zero-point energy, partition functions, and abundances are reported for each isotopologue. The energy levels in the global effective Hamiltonian model for 12C32S2 are adopted to improve the line position accuracy. This new IR list for the main isotopologue is denoted as A+I.296K. Reliable HITRAN2020 line positions are also utilized to improve the accuracy of the 32S12C34S, 32S12C33S, and 32S13C32S isotopologue line lists. The final composite line list is validated against Pacific Northwest National Laboratory experimental cross sections, showing excellent agreement. The agreement supports the quality of the composite line list and the power of synergy between experiment and theory. The new data are proposed for use in updating and expanding the CS2 data in HITRAN and other high-resolution IR databases. Supplementary files are available in Zenodo and AHED.

Keywords: exoplanet atmospheric composition; spectral line lists; astrochemistry; laboratory astrophysics; quantum-chemical calculations; potential energy surfaces; isotopic abundances; infrared spectroscopy; infrared observatories; far infrared astronomy; molecular spectroscopy
No MSP Counterparts Detected in GBT Searches of Spider Candidates 4FGL J0935.3+0901, 4FGL J1627.7+3219, and 4FGL J2212.4+0708

We performed radio searches for the "spider" millisecond pulsar (MSP) candidates 4FGL J0935.3+0901, 4FGL J1627.7+3219, and 4FGL J2212.4+0708 using the Green Bank Telescope in an attempt to detect the proposed radio counterpart of the multi-wavelength variability seen in each system. We observed using the VEGAS spectrometer, centered predominantly at 2165 MHz; however, we were also granted observations at 820 MHz for 4FGL J1627.7+3219. We performed acceleration searches on each data set using PRESTO as well as additional jerk searches of select observations. We see no evidence of a radio counterpart in any of the observations for each of the three systems at this time. Additional observations, perhaps at different orbital phases (e.g., inferior conjunction), may yield detections of an MSP in the future. Therefore, we urge continued monitoring of these systems to fully characterize the radio nature, however faint or variable, of each system.

Keywords: millisecond pulsars
Modeling the 2012 May 17 Solar Energetic Particle Event Using the AWSoM and iPATH Models

We model the 2012 May 17 solar energetic particle event by combining the AWSoM and iPATH codes. Using this combined approach, we investigate particle acceleration when the parent coronal mass ejection (CME) is still close to the Sun. We have obtained reasonable agreements between our simulation and observations made by multiple spacecraft. We follow the three-dimensional CME and the CME-driven shock from their initiation using the AWSoM code for a period of 3 hours when the shock is below ~20 Rs. Above 20 Rs, iPATH2D is used to follow the CME-driven shock. The plasma properties from the AWSoM code are fed into the iPATH model, where particle acceleration at the shock front is modelled and the instantaneous energetic particle spectra are obtained. The subsequent transport of these energetic particles in the solar wind is followed using the iPATH model. We obtain both the instantaneous particle spectra and particle fluence at 1 au, and we then compare them with observations. To account for uncertainties of magnetic field connectivity from 1 au to the shock, as well as uncertainties of the shock profiles, our model's results are obtained as an ensemble average where, instead of considering Earth as a single point location, we consider multiple locations within 10 degrees in longitude and latitude from Earth. The effect of this model uncertainty mimics that of the field line meandering, as suggested by Bian & Li, but is of different origin. We suggest that a trustworthy solar energetic particle forecast should be made in an ensemble average approach.

Keywords: solar energetic particles
HESS J1809-193: Gamma-Ray Emission by Cosmic Rays from a Past Explosion

The very-high-energy γ-ray source HESS J1809-193 has been detected by the LHAASO and HAWC observatory beyond 100 TeV energy. It is an interesting candidate for exploring the underlying mechanisms of γ-ray production due to the presence of supernova remnants, pulsars, and molecular clouds close to it. We have considered the injection of the energetic cosmic rays from a past explosion, whose reminiscent may be SNR G011.0-00.0, which is located within the extended γ-ray source HESS J1809-193. We explain the multiwavelength data from the region of HESS J1809-193 with synchrotron, inverse Compton, and bremsstrahlung emission of cosmic-ray electrons and secondary γ-ray production in interactions of cosmic-ray protons with the cold protons in the local molecular clouds within a time-dependent framework including the diffusion loss of cosmic rays. The observational data have been modeled with the secondary photons produced by the time-evolved cosmic-ray spectrum assuming the age of the explosion is 4500 yr.

Keywords: high energy astrophysics; gamma-rays; supernova remnants
Surface Conditions and Resource Accessibility at Potential Artemis Landing Sites 007 and 011

International efforts are underway to explore the Moon's south polar region with robotic and human missions. These missions will address key scientific and exploration objectives in a region rich with possibilities, designed to develop a sustained lunar presence. To assist a trade study among six potential landing sites identified for Artemis astronauts, we examined two of those sites: 007 and 011. We find that (1) many craters in the vicinity of Site 007 excavated and expose ejecta from Shackleton and Slater; additionally, numerous craters around Site 011 expose Cabeus and de Gerlache ejecta; (2) dense boulder fields occur near a large permanently shadowed region (PSR) at Site 007 and near the point of highest surface illumination in Site 011, which may affect landing and surface exploration activities; (3) despite some surface roughness, both sites 007 and 011 are traversable and contain exploration targets suitable for in situ resource utilization; (4) sites 007 and 011 receive higher average illumination than previously reported for sites 001 and 004; and (5) PSRs, seasonally shadowed regions, and cold traps at both sites offer opportunities to sample volatiles.

Keywords: selenology; lunar surface