adsabs/SciX_UAT_keywords huggingface dataset:
Quantifying the Effect of Coronagraphs on Planet Photometry with the James Webb Space Telescope

The launch of the James Webb Space Telescope (JWST) in 2021 will revolutionize exoplanetary science by providing detailed characterizations of exoplanets within the infrared range of 3-13 microns. This is of particular interest to the field of direct imaging, where empirical models that remove excess starlight from imaged extrasolar systems have proven vital to the discovery of exoplanets. pyKLIP is one of the most modern python libraries with such capabilities, allowing its users to reveal exoplanets hidden behind the starlight. However, the pyKLIP algorithms are not presently able to handle coronagraph usage with the incoming JWST data. In preparation for the launch of this telescope, we upgraded pyKLIPs ability to correct for a coronagraph's effect on the throughput of off-axis sources when determining photometry. Given the coronagraph's transmission profile, pyKLIP v2.2 is now able to successfully account for each of NIRCam's five coronagraphs.

Keywords: coronagraphic imaging; direct imaging
Systematically Measuring Ultra-diffuse Galaxies (SMUDGes). V. The Complete SMUDGes Catalog and the Nature of Ultradiffuse Galaxies

We present the completed catalog of ultradiffuse galaxy (UDG) candidates (7070 objects) from our search of the DR9 Legacy Survey images, including distance and total mass estimates for 1529 and 1436 galaxies, respectively, that we provide and describe in detail. From the sample with estimated distances, we obtain a sample of 585 UDGs (μ 0,g ≥ 24 mag arcsec-2 and r e ≥ 1.5 kpc) over 20,000 square degrees of sky in various environments. We conclude that UDGs in our sample are limited to 1010 ≲ M h /M ⊙ ≲ 1011.5 and are on average a factor of 1.5-7 deficient in stars relative to the general population of galaxies of the same total mass. That factor increases with increasing galaxy size and mass up to a factor of ~10 when the total mass of the UDG increases beyond M h = 1011 M ⊙. We do not find evidence that this factor has a dependence on the UDGs large-scale environment.

Keywords: galaxy formation; galaxy evolution; galaxy properties; low surface brightness galaxies
The Sun: Light Dark Matter and Sterile Neutrinos

Next-generation experiments allow for the possibility of testing the neutrino flavor oscillation model to very high levels of accuracy. Here, we explore the possibility that the dark matter in the current universe is made of two particles, a sterile neutrino and a very light dark matter particle. By using a 3+1 neutrino flavor oscillation model, we study how such a type of dark matter imprints the solar neutrino fluxes, spectra, and survival probabilities of electron neutrinos. The current solar neutrino measurements allow us to define an upper limit for the ratio of the mass of a light dark matter particle mφ and the Fermi constant Gφ, such that Gφ/mφ must be smaller than 1030 GF eV-1 to be in agreement with current solar neutrino data from the Borexino, Sudbury Neutrino Observatory, and Super-Kamiokande detectors. Moreover, for models with a very small Fermi constant, the amplitude of the time variability must be lower than 3% to be consistent with current solar neutrino data. We also found that solar neutrino detectors like Darwin, able to measure neutrino fluxes in the low-energy range with high accuracy, will provide additional constraints to this class of models that complement the ones obtained from the current solar neutrino detectors.

Keywords: the sun; solar neutrino problem; solar neutrinos; neutrino oscillations; neutrino telescopes; neutrino astronomy
LHS 1140 b Is a Potentially Habitable Water World

LHS 1140 b is a small planet orbiting in the habitable zone of its M4.5V dwarf host. Recent mass and radius constraints have indicated that it has either a thick H2-rich atmosphere or substantial water by mass. Here we present a transmission spectrum of LHS 1140 b between 1.7 and 5.2 μm, obtained using the NIRSpec instrument on JWST. By combining spectral retrievals and self-consistent atmospheric models, we show that the transmission spectrum is inconsistent with H2-rich atmospheres with varied size and metallicity, leaving a water world as the remaining scenario to explain the planet's low density. Specifically, a H2-rich atmosphere would result in prominent spectral features of CH4 or CO2 on this planet, but they are not seen in the transmission spectrum. Instead, the data favor a high mean molecular weight atmosphere (possibly N2 dominated with H2O and CO2) with a modest confidence. Forming the planet by accreting C- and N-bearing ices could naturally give rise to a CO2- or N2-dominated atmosphere, and if the planet evolves to or has the climate-stabilizing mechanism to maintain a moderate-size CO2/N2-dominated atmosphere, the planet could have liquid-water oceans. Our models suggest CO2 absorption features with an expected signal of 20 ppm at 4.2 μm. As the existence of an atmosphere on TRAPPIST-1 planets is uncertain, LHS 1140 b may well present the best current opportunity to detect and characterize a habitable world.

Keywords: exoplanets; habitable planets; transmission spectroscopy; astronomy data analysis; bayesian statistics; atmospheric composition; exoplanet atmospheric composition
Postexplosion Positive Jet-feedback Activity in Inner Ejecta of Core Collapse Supernovae

We conduct three-dimensional hydrodynamical simulations of weak jets that we launch into a core collapse supernova (CCSN) ejecta half an hour after the explosion and find that the interaction of the fast jets with the CCSN ejecta creates high-pressure zones that induce a backflow that results in mass accretion onto the newly born neutron star. In cases of weak jets, with a total power of ≈1045-1046 erg, the backflow mass accretion might power them up to more energetic jets by an order of magnitude. In total, the jets of the two postexplosion jet-launching episodes have enough energy to influence the morphology of the very inner ejecta, with a mass of ≈0.1 M ⊙. Our results imply that in some, probably a minority of, CCSN remnants the very inner regions might display a bipolar structure that results from postexplosion weak jets. The regions outside this part might display the morphology of jittering jets.

Keywords: core-collapse supernovae
Tidal Heating of Exomoons in Resonance and Implications for Detection

The habitability of exoplanets can be strongly influenced by the presence of an exomoon, and in some cases the exomoon itself could be a possible place for life to develop. For moons outside of the habitable zone, significant tidal heating may raise their surface temperatures enough for them to be considered habitable. Tidal heating of a moon depends on numerous factors such as eccentricity, semimajor axis, size of parent planet, and the presence of additional moons. In this work, we explore the degree of tidal heating possible for multimoon systems in resonance using a combination of semianalytic and numerical models. This demonstrates that even for a moon with zero initial eccentricity, when it moves into resonance with an outer moon, it can generate significant eccentricity and associated tidal heating. Depending on the mass ratio of the two moons, this resonance can either be short-lived (≤200 Myr) or continue to be driven by the tidal migration of the moons. This tidal heating can also assist in making the exomoons easier to discover, and we explore two scenarios: secondary eclipses and outgassing of volcanic species. We then consider hypothetical moons orbiting known planetary systems to identify which will be best suited for finding exomoons with these methods. We conclude with a discussion of current and future instrumentation and missions.

Keywords: natural satellites (extrasolar); exoplanets; tides; habitable planets
Investigating the Nature of the Luminous Ambiguous Nuclear Transient ASASSN-17jz

We present observations of the extremely luminous but ambiguous nuclear transient (ANT) ASASSN-17jz, spanning roughly 1200 days of the object's evolution. ASASSN-17jz was discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) in the galaxy SDSS J171955.84+414049.4 on UT 2017 July 27 at a redshift of z = 0.1641. The transient peaked at an absolute B-band magnitude of M B,peak = -22.81, corresponding to a bolometric luminosity of L bol,peak = 8.3 × 1044 erg s-1, and exhibited late-time ultraviolet emission that was still ongoing in our latest observations. Integrating the full light curve gives a total emitted energy of E tot = (1.36 ±0.08) × 1052 erg, with (0.80 ± 0.02) × 1052 erg of this emitted within 200 days of peak light. This late-time ultraviolet emission is accompanied by increasing X-ray emission that becomes softer as it brightens. ASASSN-17jz exhibited a large number of spectral emission lines most commonly seen in active galactic nuclei (AGNs) with little evidence of evolution. It also showed transient Balmer features, which became fainter and broader over time, and are still being detected >1000 days after peak brightness. We consider various physical scenarios for the origin of the transient, including supernovae (SNe), tidal disruption events, AGN outbursts, and ANTs. We find that the most likely explanation is that ASASSN-17jz was a SN IIn occurring in or near the disk of an existing AGN, and that the late-time emission is caused by the AGN transitioning to a more active state.

Keywords: galaxy accretion disks; accretion; active galactic nuclei; tidal disruption; supernovae
GALLIFRAY-A Geometric Modeling and Parameter Estimation Framework for Black Hole Images Using Bayesian Techniques

Recent observations of the galactic centers of M87 and the Milky Way with the Event Horizon Telescope have ushered in a new era of black-hole-based tests of fundamental physics using very long baseline interferometry (VLBI). Since it is a nascent field, there are several different modeling and analysis approaches in vogue (e.g., geometric and physical models, visibility and closure amplitudes, agnostic and multimessenger priors). We present GALLIFRAY, an open-source, Python-based framework for estimation/extraction of parameters using VLBI data. It is developed with modularity, efficiency, and adaptability as the primary objectives. This article outlines the design and usage of GALLIFRAY. As an illustration, we fit a geometric and a physical model to simulated data sets using Markov Chain Monte Carlo sampling and find good convergence of the posterior distribution. We conclude with an outline of further enhancements currently in development.

Keywords: very long baseline interferometry; astronomy data analysis; astrophysical black holes; markov chain monte carlo
On the Connection between Solar Surface Magnetic Flux and the Total Solar Irradiance

Solar surface magnetic flux evolution plays a dominant role in the variability of total solar irradiance (TSI). Different proxies of magnetic activity have been introduced to correlate solar variability and TSI. We present the daily strong flux densities (SFDs) and weak flux densities (WFDs) defined with three magnetic thresholds calculated from the Solar Dynamic Observatory/Helioseismic Magnetic Imager. TSI measurements are from the radiometers of the Variability of Solar Irradiance and Gravity Oscillations experiment on the Solar and Heliosphere Observatory, and sunspot area (SSA) is from the National Oceanic and Atmospheric Administration. We characterize the influence of the magnetic flux density variation on the TSI using the Pearson, Spearman, and percentage bend correlations and wavelet analysis between the TSI and the flux density. The Pearson's correlation shows that the TSI is negatively and strongly correlated with SFD and moderately with SSA; Spearman and 20% bend correlation shows that the TSI is moderately correlated with SFD and weakly with SSA on solar maximum, but weakly correlated on solar minimum. However, the TSI is not correlated with WFD during solar maximum and minimum. The bootstrapping tests also confirm that the influence of SFD on TSI is more significant than that of SSA. Finally, a wavelet analysis supports the idea that the SFD and TSI have a causality linkage and that the SFD dominantly influences the TSI variability on the rotational timescale.

Keywords: solar physics; solar magnetic flux emergence; solar magnetic fields; solar active regions; solar active region magnetic fields; solar magnetic reconnection
Mean-field Analysis on Large-scale Magnetic Fields at High Reynolds Numbers

Solar magnetic fields comprise an 11 yr activity cycle, represented by the number of sunspots. The maintenance of such a solar magnetic field can be attributed to fluid motion in the convection zone, i.e., a dynamo. This study conducts the mean-field analyses of the global solar dynamo simulation presented by Hotta et al. (2016). Although the study succeeds in producing coherent large-scale magnetic fields at high Reynolds numbers, the detailed physics of the maintenance of these fields have not been fully understood. This study extracts the α tensor and the turbulent magnetic diffusivity tensor β through mean-field analyses. The turbulent magnetic diffusivity exhibits a significant decrease toward high Reynolds numbers. The decrease in the turbulent magnetic diffusivity suppresses the energy conversion of large-scale field to small-scale field. This implies that the decrease in the turbulent magnetic diffusivity contributes to the maintenance of a large-scale magnetic field at high Reynolds numbers. A significant downward turbulent pumping is observed; it is enhanced in the weak phase of the large-scale field. This study proposes a cyclic reversal process of a large-scale field, which is dominantly driven by the α effect and is possibly triggered by downward pumping.

Keywords: solar convective zone; magnetohydrodynamics; solar dynamo; solar magnetic fields
The Relative Importance of Faraday Rotation and QED Birefringence for the Linear Polarization of X-Rays from Mass-accreting Black Holes

The upcoming Imaging X-ray Polarimetry Explorer (IXPE; 2-8 keV) and XL-Calibur (15-75 keV) missions will make it possible to measure the linear polarization of X-rays from mass-accreting stellar mass black holes with unprecedented sensitivity, enabling the accurate measurement of percent-level and in some cases even sub-percent-level polarization fractions. The measurements are expected to constrain the spins, inclinations, and the structure of the accretion flows of the observed black holes. The effects of Faraday rotation and birefringence of the quantum electrodynamics vacuum may impact the observable polarization fractions and angles, complicating the interpretation of the results. We estimate the importance of both effects for X-rays from stellar mass and supermassive black holes and discuss the implications of the results for the upcoming IXPE and XL-Calibur observations.

Keywords: stellar mass black holes; supermassive black holes; black hole physics; high energy astrophysics; particle astrophysics
Particle-in-cell Simulation of Energy Conversion at the Turbulent Region Downstream of the Reconnection Front

We study the energy conversion in the turbulent region (TR) downstream of the reconnection front (RF) via 2.5D particle-in-cell simulations. Our study shows that most magnetic energy is transferred into plasma in the exhaust region (ER) and the TR downstream of the RF; the latter is formed due to the electron Kelvin-Helmholtz instability (KHI). Unlike the energy conversion in the ER, the energy conversion in the TR is mainly balanced by its in-plane component (E x J x +E z J z ). We further find that the time evolution of the integrated energy conversion in the TR is strongly correlated with the time evolution of the electron KHI and secondary reconnection. The KHI feeds on the electron kinetic energy to grow, and electron vortices are formed, correspondently. The energy is transferred to ions through a nonideal electric field associated with those electron vortices after the KHI is well developed. Finally, the electron vortices are collapsed due to the secondary reconnection among those vortices. The power law of the magnetic energy spectra also shows a slope near -5/3 at wavenumbers larger than the ion scale when the KHI is fully developed.

Keywords: solar magnetic reconnection; plasma physics; space plasmas; astronomical simulations; interplanetary turbulence
The Electric Field outward of Saturn's Main Rings

Cassini data are consistent with a global electric field in Saturn's magnetosphere that points approximately antisunward. The inner radial extent of this field was initially established using Saturn orbit insertion data but measurements of ultrarelativistic electrons from that pass cast some doubt on whether the electric field reaches all the way to the A ring. It was not until the so-called ring-grazing and proximal orbits near the end of the mission in 2017 that relevant data were again obtained on magnetic field lines that connect to the region just outward of the main rings. Here we report on the energetic charged particle data during those orbits, showing that electron observations at a wide range of energies are consistent with an electric field that influences charged particle drift paths near the outer edge of the A ring. We include a very detailed analysis of Cassini's ultrarelativistic electron measurements (channel E7 in the text) and argue they provide no information about the electric field. This result further strengthens the case of several studies that have used the presence of the electric field to explain signatures of acceleration in the data.

Keywords: planetary rings; magnetic fields
The Fast X-Ray Transient XRT 210423 and Its Host Galaxy

Fast X-ray Transients (FXTs) are X-ray flares with durations ranging from a few hundred seconds to a few hours. Possible origins include the tidal disruption of a white dwarf by an intermediate-mass black hole, a supernova shock breakout, or a binary neutron star merger. We present the X-ray light curve and spectrum as well as deep optical imaging of the FXT XRT 210423, which has been suggested to be powered by a magnetar produced in a binary neutron star merger. Our Very Large Telescope and Gran Telescopio Canarias (GTC) observations began on 2021 May 6, thirteen days after the onset of the flare. No transient optical counterpart is found in the 1.″ (3σ) X-ray uncertainty region of the source to a depth g s = 27.0 AB mag. (We use the word "counterpart" for any transient light in a wave band other than the original X-ray detection wave band, whereas the word "host" refers to the host galaxy.) A candidate host lies within the 1.″ X-ray uncertainty region with a magnitude of 25.9 ± 0.1 in the GTC/HiPERCAM g s filter. Due to its faintness, it was not detected in other bands, precluding a photometric redshift determination. We detect two additional candidate host galaxies: one with z spec = 1.5082 ± 0.0001 and an offset of 4.″2 ± 1.″ (37 ± 9 kpc) from the FXT, and another one with ${z}_{\mathrm{phot}}={1.04}_{-0.14}^{+0.22}$ and an offset of 3.″6 ± 1.″ (30 ± 8 kpc). Based on the properties of all the prospective hosts, we favor a binary neutron star merger, as previously suggested in the literature, as the explanation for XRT 210423.

Keywords: x-ray transient sources; tidal disruption; magnetars; supernovae; dwarf galaxies; globular star clusters
Observations of Nine Millisecond Pulsars at 8600 MHz Using the TMRT

We report detection results of nine millisecond pulsars (MSPs) at 8600 MHz using simultaneous 2250 and 8600 MHz observations conducted with the Shanghai Tian Ma Radio Telescope. Mainly benefiting from updated ephemerids with 2250 MHz observations, integrated profiles of all nine MSPs at 8600 MHz are successfully obtained by coherently adding multi-epoch (3-83 epochs) observation data spanning from 19-1210 days, which significantly increases the number of MSPs with published profiles (from 4 to 11) above 8000 MHz, as seven of our target MPSs had no related results previously. Combining our new flux density and pulse width measurements with previous low-frequency results, we study their integrated profile evolution and spectral behaviors in a wider frequency range. We find their component separations and pulse widths remain almost constant, which is consistent with previous findings. While dramatic evolution of integrated profiles exists at low frequencies, we observe a potential end of the related evolution around 5 GHz in eight MSPs. The spectra of four MSPs are found to deviate from a single power law, and we fit them with a broken power law. The change in the profile of PSR J1713+0747, which started around MJD 59320-59321, seems to be more prominent as the observation frequency increases. Compared with the effects of the interstellar medium, we prefer to explain this event as some changes in the magnetosphere. We also find its integrated profile possibly had not recovered to the pre-event state until MJD 59842-59857.

Keywords: millisecond pulsars; radio pulsars
Measuring the Variance of the Macquart Relation in Redshift–Extragalactic Dispersion Measure Modeling

The Macquart relation describes the correlation between the dispersion measure (DM) of fast radio bursts (FRBs) and the redshift z of their host galaxies. The scatter of the Macquart relation is sensitive to the distribution of baryons in the intergalactic medium including those ejected from galactic halos through feedback processes. The variance of the distribution in DMs from the cosmic web (DMcosmic) is parameterized by a fluctuation parameter F. In this work, we present a new measurement of F using 78 FRBs of which 21 have been localized to host galaxies. Our analysis simultaneously fits for the Hubble constant H 0 and the DM distribution due to the FRB host galaxy. We find that the fluctuation parameter is degenerate with these parameters, most notably H 0, and use a uniform prior on H 0 to measure ${\mathrm{log}}_{10}F\gt -0.86$ at the 3σ confidence interval and a new constraint on the Hubble constant ${H}_{0}={85.3}_{-8.1}^{+9.4}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ . Using a synthetic sample of 100 localized FRBs, the constraint on the fluctuation parameter is improved by a factor of ∼2. Comparing our F measurement to simulated predictions from cosmological simulation (IllustrisTNG), we find agreement between redshifts 0.4 < z and z < 2.0. However, at z < 0.4, the simulations underpredict F, which we attribute to the rapidly changing extragalactic DM excess distribution at low redshift.

Keywords: radio transient sources; radio bursts; cosmological parameters; intergalactic medium; hubble constant