Sazuna/UAT_keywords huggingface dataset:
Discovery of a New Redback Millisecond Pulsar Candidate: 4FGL J0940.3-7610. We have discovered a new candidate redback millisecond pulsar binary near the center of the error ellipse of the bright unassociated Fermi-LAT γ-ray source 4FGL J0940.3-7610. The candidate counterpart is a variable optical source that also shows faint X-ray emission. Optical photometric and spectroscopic monitoring with the SOAR telescope indicates that the companion is a low-mass star in a 6.5 hr orbit around an invisible primary, showing both ellipsoidal variations and irradiation and consistent with the properties of known redback millisecond pulsar binaries. Given the orbital parameters, preliminary modeling of the optical light curves suggests an edge-on inclination and a low-mass (∼1.2-1.4 M⊙) neutron star, along with a secondary mass somewhat more massive than the typical ≳0.4 M⊙. This combination of inclination and secondary properties could make radio eclipses more likely for this system, explaining its previous nondiscovery in radio pulsation searches. Hence, 4FGL J0940.3-7610 may be a strong candidate for a focused search for γ-ray pulsations to enable the future detection of a millisecond pulsar.

Keywords: Neutron stars, Gamma-ray sources, X-ray binary stars, Millisecond pulsars
A Broadband X-Ray View of the Precessing Accretion Disk and Pre-eclipse Dip in the Pulsar Her X-1 with NuSTAR and XMM-Newton. We present a broadband X-ray timing study of the variations in pulse behavior with the superorbital cycle in the low-mass X-ray binary Her X-1. This source shows a 35 day superorbital modulation in X-ray flux that is likely caused by occultation by a warped, precessing accretion disk. Our data set consists of four joint XMM-Newton and NuSTAR observations of Her X-1 which sample a complete superorbital cycle. We focus our analysis on the first and fourth observations, which occur during the bright "main-on" phase, because these observations have strongly detected pulsations. We added an archival XMM-Newton observation during the "short-on" phase of the superorbital cycle because our observations at that phase are lower in signal to noise. We find that the energy-resolved pulse profiles show the same shape at similar superorbital phases, and the profiles are consistent with expectations from a precessing disk. We demonstrate that a simple precessing accretion disk model is sufficient to reproduce the observed pulse profiles. The results of this model suggest that the similarities in the observed pulse profiles are due to reprocessing by a precessing disk that has returned to its original precession phase. We determine that the broadband spectrum is well fit by an absorbed power law with a soft blackbody component and show that the spectral continuum also exhibits a dependence on the superorbital cycle. We also present a brief analysis of the energy-resolved light curves of a pre-eclipse dip, which shows soft X-ray absorption and hard X-ray variability during the dip.

Keywords: Low-mass x-ray binary stars, Pulsars
Hierarchical Inference with Bayesian Neural Networks: An Application to Strong Gravitational Lensing. In the past few years, approximate Bayesian Neural Networks (BNNs) have demonstrated the ability to produce statistically consistent posteriors on a wide range of inference problems at unprecedented speed and scale. However, any disconnect between training sets and the distribution of real-world objects can introduce bias when BNNs are applied to data. This is a common challenge in astrophysics and cosmology, where the unknown distribution of objects in our universe is often the science goal. In this work, we incorporate BNNs with flexible posterior parameterizations into a hierarchical inference framework that allows for the reconstruction of population hyperparameters and removes the bias introduced by the training distribution. We focus on the challenge of producing posterior PDFs for strong gravitational lens mass model parameters given Hubble Space Telescope-quality single-filter, lens-subtracted, synthetic imaging data. We show that the posterior PDFs are sufficiently accurate (statistically consistent with the truth) across a wide variety of power-law elliptical lens mass distributions. We then apply our approach to test data sets whose lens parameters are drawn from distributions that are drastically different from the training set. We show that our hierarchical inference framework mitigates the bias introduced by an unrepresentative training set's interim prior. Simultaneously, we can precisely reconstruct the population hyperparameters governing our test distributions. Our full pipeline, from training to hierarchical inference on thousands of lenses, can be run in a day. The framework presented here will allow us to efficiently exploit the full constraining power of future ground- and space-based surveys (https://github.com/swagnercarena/ovejero).

Keywords: Cosmology, Strong gravitational lensing, Convolutional neural networks, Computational methods, Hierarchical models
Black Hole and Galaxy Coevolution in Moderately Luminous Active Galactic Nuclei at z ∼ 1.4 in SXDF. We investigate the relation of black hole mass versus host stellar mass and that of mass accretion rate versus star formation rate (SFR) in moderately luminous ( $\mathrm{log}{L}_{\mathrm{bol}}\sim 44.5\mbox{--}46.5\ \mathrm{erg}\,{{\rm{s}}}^{-1}$ &lt;!-- --&gt; ), X-ray selected broad-line active galactic nuclei (AGNs) at z = 1.18-1.68 in the Subaru/XMM-Newton Deep Field. The far-infrared to far-ultraviolet spectral energy distributions of 85 AGNs are reproduced with the latest version of Code Investigating GALaxy Emission (CIGALE), where the AGN clumpy torus model SKIRTOR is implemented. Most of their hosts are confirmed to be main-sequence star-forming galaxies. We find that the mean ratio of the black hole mass (MBH) to the total stellar mass (Mstellar) is $\mathrm{log}{M}_{\mathrm{BH}}/{M}_{\mathrm{stellar}}=-2.2$ &lt;!-- --&gt; ,which is similar to the local black hole-to-bulge mass ratio. This suggests that if the host galaxies of these moderately luminous AGNs at z ∼ 1.4 are dominated by bulges, they already established the local black hole mass-bulge mass relation; if they are disk dominant, their black holes are overmassive relative to the bulges. The AGN bolometric luminosities and SFR show a good correlation with ratios higher than that expected from the local black hole-to-bulge mass relation, suggesting that these AGNs are in a SMBH-growth dominant phase.

Keywords: Supermassive black holes, Active galaxies, Active galactic nuclei
Scalaron Gravity near Sagittarius A*: Investigation of Spin of the Black Hole and Observing Requirements. In this paper the author applies the scalaron gravity field and corresponding Yukawa coupling (derived by Kalita from the consideration of quantum vacuum fluctuations with UV and IR scales) to examine the scales of stellar orbits near the Galactic Center black hole, which can be probed by upcoming astrometric facilities for constraining modified gravity. Through the assumption that the pericenter shift of stellar orbits becomes of the order of spin and quadrupole moment effects of the black hole, it is found that for semimajor axes bounded below by time scales of gravitational wave emission and stellar age and above by S-2 like orbits (a = 990 au) the black hole spin with 0.1 ≤ χ ≤ 0.980 is eligible to probe scalaron masses within (10-22-10-18) eV and also the scalaron coupling, α = 2.73 × 10-4 derived earlier from quantum vacuum fluctuations. The orbital eccentricities are considered as e = 0.1, 0.5, and 0.9. Astrometric categories with σ = 10, 50, and 100 μas are used to probe the time scales and number of observing campaigns required for simultaneously constraining scalaron mass and black hole spin. It is found that extraction of black hole spin is possible within a = (74-433) au through 10 μas facilities. The present analysis is realized to be an independent opportunity to simultaneously constrain scalaron coupling, black hole spin, and tidal charge and hence to reveal the true nature of the spacetime structure of our nearest supermassive black hole.

Keywords: Black hole physics, Galactic center
Resonances in a Coronal Loop Driven by Torsional Alfvén Waves Propagating from the Photosphere. There is increasing evidence that magnetohydrodynamic waves play an important role in the propagation and dissipation of energy in the solar atmosphere. Here we investigate how torsional Alfvén waves driven at the photosphere can transport energy to an overlying coronal magnetic loop and explore their ability to heat the plasma. We consider a coronal loop whose feet are embedded in the partially ionized chromosphere. A broadband driver at the photosphere excites torsional Alfvén waves that propagate upward to the coronal loop. By means of numerical computations under the stationary-state assumption, we study the transmission of wave energy to the loop and the heating associated with ohmic diffusion and ion-neutral collisions. We find that wave transmission to the loop is heavily affected by the presence of cavity resonances when the frequency of the driver matches an eigenfrequency of the loop. A tremendous amount of wave energy is channeled to the coronal loop for those particular frequencies. The transmitted energy surpasses by many orders of magnitude the requirements to balance thermal radiation. However, dissipation is so weak in the coronal plasma that only a tiny percentage of the energy budget is converted into heat, which is not enough to compensate for radiative losses. Most of the energy simply leaks back to the chromosphere. Conversely, dissipation is much more efficient in the lower atmosphere, and wave heating can locally balance a significant fraction of radiation in the chromosphere. We argue that nonlinear effects such as turbulence triggered by the Kelvin-Helmholtz instability should enhance the heating efficiency at coronal heights.

Keywords: Solar physics
Three-dimensional Climate Simulations for the Detectability of Proxima Centauri b. The discovery of a planet orbiting around Proxima Centauri, the closest star to the Sun, opens new avenues for the remote observations of the atmosphere and surface of an exoplanet, Proxima b. To date, three-dimensional (3D) general circulation models (GCMs) are the best available tools to investigate the properties of the exo-atmospheres, waiting for the next generation of space- and ground-based telescopes. In this work, we use the Planet Simulator (PlaSim), an intermediate-complexity, flexible and fast 3D GCM, suited to handle all the orbital and physical parameters of a planet and to study the dynamics of its atmosphere. Assuming an Earth-like atmosphere and a 1:1 spin/orbit configuration (tidal locking), our simulations of Proxima b are consistent with a dayside open ocean planet with a superrotating atmosphere. Moreover, because of the limited representation of the radiative transfer in PlaSim, we compute the spectrum of the exoplanet with an offline radiative transfer code with a spectral resolution of 1 nm. This spectrum is used to derive the thermal phase curves for different orbital inclination angles. In combination with instrumental detection sensitivities, the different thermal phase curves are used to evaluate observation conditions at ground level (e.g., ELT) or in space (e.g., James Webb Space Telescope (JWST)). We estimated the exposure time to detect the Proxima b (assuming an Earth-like atmosphere) thermal phase curve in the far-IR with JWST with signal-to-noise ratio ≃1. Under the hypothesis of total noise dominated by shot noise, neglecting other possible extra contribution producing a noise floor, the exposure time is equal to 5 hr for each orbital epoch.

Keywords: Ocean planets, Exoplanets, Astronomical simulations, Infrared photometry, Light curves, Two-color diagrams, Infrared telescopes, Planetary climates, Exoplanet detection methods, Exoplanet atmospheres
The Star Formation History of Eridanus II: On the Role of Supernova Feedback in the Quenching of Ultrafaint Dwarf Galaxies. Eridanus II (Eri II) is an ultrafaint dwarf (UFD) galaxy (MV = -7.1) located at a distance close to the Milky Way virial radius. Early shallow color-magnitude diagrams (CMDs) indicated that it possibly hosted an intermediate-age or even young stellar population, which is unusual for a galaxy of this mass. In this paper, we present new Hubble Space Telescope/Advanced Camera for Surveys CMDs reaching the oldest main-sequence turnoff with excellent photometric precision and derive a precise star formation history (SFH) for this galaxy through CMD fitting. This SFH shows that the bulk of the stellar mass in Eri II formed in an extremely short star formation burst at the earliest possible time. The derived star formation rate profile has a width at half maximum of 500 Myr and reaches a value compatible with null star formation 13 Gyr ago. However, tests with mock stellar populations and with the CMD of the globular cluster M92 indicate that the star formation period could be shorter than 100 Myr. From the quantitative determination of the amount of mass turned into stars in this early star formation burst ( ∼2 × 105 M⊙) we infer the number of supernova (SN) events and the corresponding energy injected into the interstellar medium. For reasonable estimates of the Eri II virial mass and values of the coupling efficiency of the SN energy, we conclude that Eri II could be quenched by SN feedback alone, thus casting doubts on the need to invoke cosmic reionization as the preferred explanation for the early quenching of old UFD galaxies. * Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 14224 and 14234.

Keywords: Local Group, Galaxy formation, Dwarf galaxies, Galaxy evolution, Galaxy quenching
Source Counts Spanning Eight Decades of Flux Density at 1.4 GHz. Brightness-weighted differential source counts S2n(S) spanning the eight decades of flux density between 0.25 μJy and 25 Jy at 1.4 GHz were measured from (1) the confusion brightness distribution in the MeerKAT DEEP2 image below 10 μJy, (2) counts of DEEP2 sources between 10 μJy and 2.5 mJy, and (3) counts of NVSS sources stronger than 2.5 mJy. We present our DEEP2 catalog of 1.7 × 104 discrete sources complete above S = 10 μJy over Ω = 1.04 deg2. The brightness-weighted counts converge as S2n(S) ∝ S1/2 below S = 10 μJy, so &gt;99% of the ΔTb ∼ 0.06 K sky brightness produced by active galactic nuclei and ≈96% of the ΔTb ∼ 0.04 K added by star-forming galaxies has been resolved into sources with S ≥ 0.25 μJy. The ΔTb ≈ 0.4 K excess brightness measured by ARCADE 2 cannot be produced by faint sources smaller than ≈50 kpc if they cluster like galaxies.

Keywords: Radio galaxies, Star formation, Galaxy evolution, Galaxy counts
Daniel Mögling's Sunspot Observations in 1626-1629: A Manuscript Reference for the Solar Activity before the Maunder Minimum. The sunspots have been observed since 1610, and their group numbers have been used for evaluating the amplitude of solar activity. Daniel Mögling recorded his sunspot observations for more than 100 days in 1626-1629 and formed a significant data set of sunspot records before the Maunder Minimum. Here we have analyzed his original manuscripts in the Universitäts- und Landesbibliothek Darmstadt to review Mögling's personal profile and observational instruments and derived the number and positions of the recorded sunspot groups. In his manuscript, we have identified 134 days with an exact sunspot group number and 3 days of additional descriptions. Our analyses have completely revised the observational dates and group numbers, added 19 days of hitherto overlooked observations, and removed 8 days of misinterpreted observations. We have also revisited the sunspot observations of Schickard and Hortensius and revised their data. These results have been compared with the contemporary observations. Moreover, we have derived the sunspot positions from his sunspot drawings and located them at 2°-23° in heliographic latitude in both solar hemispheres. Contextualized with contemporary observations, these results indicate their temporal migration to lower heliographic latitudes and emphasize their location in the declining phase of solar cycle -12 in the 1620s. Mögling's observations were probably conducted using a pinhole and camera obscura, which likely made him underestimate the sunspot group number by ≥33%-52%. This underestimation should be noted upon comparison with modern data sets.

Keywords: Solar cycle, Sunspot groups, Sunspot number, History of astronomy, Maunder minimum, Solar-terrestrial interactions, Sunspot cycle
Parametric Simulation Studies on the Wave Propagation of Solar Radio Emission: The Source Size, Duration, and Position. The observed features of the radio source indicate that the waves of solar radio bursts are convoluted with complex propagation effects. In this work, we perform ray-tracing simulations on radio wave transport in the corona and interplanetary region with anisotropic electron density fluctuations. For the first time, the variation of the apparent source size, burst duration, and source position for the fundamental emission and harmonic emission at the frequency of 35 MHz are simulated as a function of the anisotropic parameter α and the angular scattering rate coefficient η = ɛ2/h0, where ɛ2 = ⟨δn2⟩/n2 is the density fluctuation level and h0 is its correlation length near the wave excitation site. It is found that isotropic fluctuations produce a much larger decay time than a highly anisotropic fluctuation for fundamental emission. By comparing the observed duration and source size with the simulation results in the parameter space, we can estimate the scattering coefficient and the anisotropic parameter η = 8.9 × 10-5 km-1 and α = 0.719 with a point pulse source assumption. Position offsets due to wave scattering and refraction can produce the co-spatial of the fundamental and harmonic waves in the observation of some type III radio bursts. The visual speed due to the wave propagation effect can reach 1.5c for η = 2.4 × 10-4 km-1 and α = 0.2 for the fundamental emission in the sky plane, accompanied with large expansion rate of the source size. The direction of the visual speed is mostly identical to the direction of the offset, thus, for the observation aimed at obtaining the source position, the source centroid at the starting time is closer to the wave excitation site.

Keywords: Solar coronal radio emission, Radiative transfer simulations, Solar radio emission, Radio astronomy
Revealing Ionization Conditions of Sz 102 with Spatially Resolved [Ne III] Microjets. Forbidden neon emission lines from small-scale microjets can probe high-energy processes in low-mass young stellar systems. We obtained spatially resolved [Ne III] spectra in the microjets from the classical T Tauri Star Sz 102 using the Hubble Space Telescope Imaging Spectrograph at a spatial resolution of ∼0"1. The blueshifted and redshifted [Ne III] emission both peak in intensity within ∼0"1 of the star and gradually decay along the flow outward to ∼0"24. The spatial distribution and extent of the [Ne III] microjet is consistent with a jet that is ionized close to the base and subsequently recombines on a longer timescale than the flow time. Ca II H and K lines are also detected from the redshifted microjet with a line full-width at half-maximum of ∼170 km s-1, consistent with those of other forbidden emission lines, atop a 300 km s-1 wide stellar component. The launching radius of the Sz 102 jet, inferred from the observed line centroids and the range of inclination angles and stellar masses from the literature, is on the order of ∼0.03 au. The possible proximity of the launching region to the star allows immediate ionization without distance dilution from the circumstellar ionization sources, most likely keV X-ray flares generated by magnetic reconnection events in the star--disk system, to sustain the observed [Ne III] flux.

Keywords: Jets, X-ray stars, Classical T Tauri stars
The Intensity and Evolution of the Extreme Solar and Geomagnetic Storms in 1938 January. Major solar eruptions occasionally direct interplanetary coronal mass ejections (ICMEs) to Earth and cause significant geomagnetic storms and low-latitude aurorae. While individual extreme storms are significant threats to modern civilization, storms occasionally appear in sequence, acting synergistically, and cause "perfect storms" on Earth. The stormy interval in 1938 January was one of such cases. Here, we analyze the contemporary records to reveal its time series on their source active regions, solar eruptions, ICMEs, geomagnetic storms, low-latitude aurorae, and cosmic-ray (CR) variations. Geomagnetic records show that three storms occurred successively on January 17/18 (Dcx ≈ -171 nT), January 21/22 (Dcx ≈ -328 nT), and January 25/26 (Dcx ≈ -336 nT). The amplitudes of the CR variations and storm sudden commencements (SSCs) show the impact of the first ICME as the largest (≈6% decrease in CR and 72 nT in SSC) and the ICMEs associated with the storms that followed as more moderate (≈3% decrease in CR and 63 nT in SSC; ≈2% decrease in CR and 63 nT in SSC). Interestingly, a significant solar proton event occurred on January 16/17 and the Cheltenham ionization chamber showed a possible ground-level enhancement. During the first storm, aurorae were less visible at midlatitudes, whereas, during the second and third storms, the equatorward boundaries of the auroral oval were extended down to 40.3° and 40.0° in invariant latitude. This contrast shows that the initial ICME was probably faster, with a higher total magnitude but a smaller southward component.

Keywords: Geomagnetic fields, Solar flares, Solar energetic particles, Sunspots, Forbush effect, Solar active regions, Solar coronal mass ejections, Solar-terrestrial interactions, Cosmic rays
Ultra-steep-spectrum Radio "Jellyfish" Uncovered in A2877. We report on the discovery of a mysterious ultra-steep-spectrum (USS) synchrotron source in the galaxy cluster A2877. We have observed the source with the Murchison Widefield Array at five frequencies across 72-231 MHz and found the source to exhibit strong spectral curvature over this range, as well as the steepest known spectra of a synchrotron cluster source, with a spectral index across the central three frequency bands of $\alpha =-{5.97}_{-0.48}^{+0.40}$ &lt;!-- --&gt; . Higher-frequency radio observations, including a deep observation with the Australia Telescope Compact Array, fail to detect any of the extended diffuse emission. The source is approximately 370 kpc wide and bears an uncanny resemblance to a jellyfish with two peaks of emission and long tentacles descending south toward the cluster center. While the "USS Jellyfish" defies easy classification, we here propose that the phenomenon is caused by the reacceleration and compression of multiple aged electron populations from historic active galactic nucleus (AGN) activity, a so-called "radio phoenix," by an as yet undetected weak cluster-scale mechanism. The USS Jellyfish adds to a growing number of radio phoenix in cool-core clusters with unknown reacceleration mechanisms; as the first example of a polyphoenix, however, this implies that the mechanism is on the scale of the cluster itself. Indeed, we show that in simulations, emission akin to the USS Jellyfish can be produced as a short-lived transient phase in the evolution of multiple interacting AGN remnants when subject to weak external shocks.

Keywords: Galaxy clusters, Plasma physics, Spectral index, Intracluster medium, Radio astronomy