Sazuna/UAT_keywords huggingface dataset:
A Dynamic Deep-learning Model for Generating a Magnetogram Sequence from an SDO/AIA EUV Image Sequence. The solar magnetic field dominates solar activities in the solar atmosphere, such as solar flares and coronal mass ejections (CMEs). The Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) has been in operation from 2010, providing a full-disk photospheric magnetogram. However, with a single view of observation, SDO/HMI cannot provide a global view of the Sun at the same time, so the farside of the Sun is blind to us. The Solar Terrestrial Relations Observatory (STEREO) provides two different views of the Sun with complementary viewing angles relative to SDO/HMI. However, it did not carry a magnetograph, but an extreme-ultraviolet (EUV) imager. Fortunately, deep learning has been proved to generate a solar farside magnetogram from STEREO farside EUV observation. Although a single generated magnetogram is morphologically very similar to ground truth, the sequence of the generated magnetogram has noticeable magnetic field fluctuation, which cannot be ignored when it is displayed as a time series, especially at an active region. This fluctuation is represented by sudden magnetic polarity reversal and drifting of magnetic field distribution. To mitigate this problem, a novel dynamic deep-learning model by integrating a convolutional gated recurrent units (convGRU) model into a pix2pix baseline is proposed in this paper. It can generate a sequence of a magnetogram with smooth transition among consecutive magnetograms by exploring spatio-temporal information of an input EUV image sequence. From both quantitative and qualitative comparisons, the proposed model can generate a magnetogram sequence more close to real observation.

Keywords: Detection, Solar active regions, Convolutional neural networks
Universal Scaling Laws for Solar and Stellar Atmospheric Heating: Catalog of Power-law Index between Solar Activity Proxies and Various Spectral Irradiances. The formation of extremely hot outer atmospheres is one of the most prominent manifestations of magnetic activity common to late-type dwarf stars, including the Sun. It is widely believed that these atmospheric layers, the corona, transition region, and chromosphere, are heated by the dissipation of energy transported upwards from the stellar surface by the magnetic field. This is signified by the spectral line fluxes at various wavelengths, scaled with power-law relationships against the surface magnetic flux over a wide range of formation temperatures, which are universal to the Sun and Sunlike stars of different ages and activity levels. This study describes a catalog of power-law indices between solar activity proxies and various spectral line fluxes. Compared to previous studies, we expanded the number of proxies, which now includes the total magnetic flux, total sunspot number, total sunspot area, and the F10.7 cm radio flux, and further enhanced the number of spectral lines by a factor of 2. This provides the data to study in detail the flux-flux scaling laws from the regions specified by the temperatures of the corona (log(T/K) = 6-7) to those of the chromosphere (log(T/K) ~ 4), as well as the reconstruction of various spectral line fluxes of the Sun in the past, F-, G-, and K-type dwarfs, and the modeled stars.

Keywords: Solar analogs, G dwarf stars, Stellar chromospheres, Solar spectral irradiance, Solar corona, Solar magnetic fields, Solar transition region, Stellar coronae, Solar chromosphere
Time-dependent Lattice Cross Sections and Line Ratios for Solar Wind Charge Exchange: Bare Ne Incident on Atomic H and He. Charge exchange (CX) between highly charged ions and neutrals within the geocorona and heliosphere introduces a problematic background for every X-ray observation. For H-like ions the ℓ states within each n shell are degenerate. The majority of CX spectral models rely on calculated n-resolved cross sections, and the distribution of ℓ states is assumed to follow one of several analytical expressions. Laboratory data to validate these distributions at solar wind velocities is not available. Explicitly velocity-dependent calculations of n ℓ-resolved CX cross sections using the time-dependent lattice (TDL) method for Ne10+ incident on atomic H and He at 1-5 keV amu-1 are reported. The cross sections are incorporated into a radiative cascade model, and the influence of n- and n ℓ-resolved cross sections on possibly diagnostic emission line ratios is investigated. Comparisons of the ℓ distribution extracted from the TDL cross sections to the predominantly used analytical distributions reveals a consensus among n and n ℓ-resolved data at solar wind velocities, suggesting a statistical distribution is most appropriate for CX collisions involving atomic H. No consensus is found for atomic He targets, and the ℓ distribution extracted from n ℓ-resolved cross sections appears most appropriate. Open questions related to CX are discussed with emphasis on experimental methods to resolve them. Spectral measurements at an electron beam ion trap facility are planned to benchmark the presented cross section data.

Keywords: Charge exchange recombination, Solar wind
Binary-star Wave Front Control Based on a Common-path Visible Nulling Coronagraph. Exoplanets around multiple-star systems are interesting targets for direct detection. However, it is difficult to suppress unwanted light from all stars in a system. For direct detection of the exoplanets around multiple-star systems, we propose using common-path visible nulling coronagraphs (CP-VNCs). CP-VNCs can suppress diffracted light from stars located on a central null fringe. In addition, a wave front control system is installed to generate a dark hole by rejecting residual stellar speckles of CP-VNCs. For this purpose, spatial light modulators (SLMs) have the ability to generate a dark hole over a wide field on the order of hundreds of λ/D (where λ is the wavelength of light and D is the telescope diameter), owing to their large number of pixels. We perform a laboratory demonstration of high-contrast observation around a binary-star system model using a CP-VNC combined with an SLM. First, we simulate a high-contrast observation over a region close to one of two stars by generating a square dark hole with side lengths of 40 λ 0/D (where λ 0 is the central wavelength of the light sources). The center of the square region was located about 35 λ 0/D and 79 λ 0/D from each star. Measurements of this first scenario find a mean contrast over the dark hole of 3.5 × 10-8. Second, observation of a region with identical separation (100 λ 0/D) from both stars is also demonstrated. In this scenario, a mean contrast of 2.0 × 10-8 is achieved over a circular dark hole with a diameter of 40 λ 0/D.

Keywords: Binary stars, Exoplanets, Coronagraphic imaging, Astronomical techniques, Direct imaging, Exoplanet detection methods
The LSST Era of Supermassive Black Hole Accretion Disk Reverberation Mapping. The Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) will detect an unprecedentedly large sample of actively accreting supermassive black holes with typical accretion disk (AD) sizes of a few light days. This brings us to face challenges in the reverberation mapping (RM) measurement of AD sizes in active galactic nuclei using interband continuum delays. We examine the effect of LSST cadence strategies on AD RM using our metric AGN_TimeLagMetric. It accounts for redshift, cadence, the magnitude limit, and magnitude corrections for dust extinction. Running our metric on different LSST cadence strategies, we produce an atlas of the performance estimations for LSST photometric RM measurements. We provide an upper limit on the estimated number of quasars for which the AD time lag can be computed within 0 &lt; z &lt; 7 using the features of our metric. We forecast that the total counts of such objects will increase as the mean sampling rate of the survey decreases. The AD time lag measurements are expected for &gt;1000 sources in each deep drilling field (DDF; (10 deg2)) in any filter, with the redshift distribution of these sources peaking at z ≈ 1. We find the LSST observation strategies with a good cadence (≲5 days) and a long cumulative season (~9 yr), as proposed for LSST DDF, are favored for the AD size measurement. We create synthetic LSST light curves for the most suitable DDF cadences and determine RM time lags to demonstrate the impact of the best cadences based on the proposed metric.

Keywords: Accretion, Reverberation mapping, Time domain astronomy, Quasars
Improved AI-generated Solar Farside Magnetograms by STEREO and SDO Data Sets and Their Release. Here we greatly improve artificial intelligence (AI)-generated solar farside magnetograms using data sets from the Solar Terrestrial Relations Observatory (STEREO) and Solar Dynamics Observatory (SDO). We modify our previous deep-learning model and configuration of input data sets to generate more realistic magnetograms than before. First, our model, which is called Pix2PixCC, uses updated objective functions, which include correlation coefficients (CCs) between the real and generated data. Second, we construct input data sets of our model: solar farside STEREO extreme-ultraviolet (EUV) observations together with nearest frontside SDO data pairs of EUV observations and magnetograms. We expect that the frontside data pairs provide historic information on magnetic field polarity distributions. We demonstrate that magnetic field distributions generated by our model are more consistent with the real ones than previously, in consideration of several metrics. The averaged pixel-to-pixel CC for full disk, active regions, and quiet regions between real and AI-generated magnetograms with 8 × 8 binning are 0.88, 0.91, and 0.70, respectively. Total unsigned magnetic flux and net magnetic flux of the AI-generated magnetograms are consistent with those of real ones for the test data sets. It is interesting to note that our farside magnetograms produce polar field strengths and magnetic field polarities consistent with those of nearby frontside magnetograms for solar cycles 24 and 25. Now we can monitor the temporal evolution of active regions using solar farside magnetograms by the model together with the frontside ones. Our AI-generated solar farside magnetograms are now publicly available at the Korean Data Center for SDO (http://sdo.kasi.re.kr).

Keywords: The Sun, Convolutional neural networks, Astronomy data analysis, Solar magnetic fields
A Swift X-Ray View of the SMS4 Sample-X-Ray Properties of 31 Quasars and Radio Galaxies. We present Neil Gehrels Swift Observatory (hereafter Swift) observations of 31 sources from the SMS4 catalog, a sample of 137 bright radio sources originally designed to extend the well-studied 3CRR radio sample to the Southern Hemisphere. All these sources had no Chandra or XMM-Newton observations: 24 of these were observed with Swift through a dedicated proposal in 2015, and data for the remaining seven were retrieved from the Swift archive. The reduction and analysis of data collected by the Swift X-ray Telescope (XRT) led to 20 detections in the 0.3-10 keV band. We provide details of the X-ray emission in this band for these 20 detections, as well as upper limits for the remaining 11 SMS4 sources. When statistics allowed, we investigated the extent of the X-ray emission and the hardness ratio, and we carried out a spectral analysis. We matched the 20 X-ray-detected sources with infrared (AllWISE, CatWISE2020) and optical (GSC 2.3.2, DES DR2) catalogs to establish associations with infrared and optical sources and compared our results with previously published counterparts in these bands. Requiring a detection in both the infrared and optical bands to establish a candidate counterpart for our X-ray detections, we obtain reliable counterparts for 18 sources, while the remaining two sources need further investigation to establish firm identifications. In the infrared, we confirm 12 previously established counterparts and provide six new candidates. In the optical, we find agreement with 13 previously established counterparts, while we provide an alternative candidate for five SMS4 sources. We find that ~35% of all the SMS4 sources lie below the lower limit of 10.9 Jy for the flux density at 178 MHz established for the 3CRR sample, at variance with the values extrapolated using measurements at higher frequencies. Therefore, for future studies where flux-density-limited samples are needed, we encourage the use of the more recent G4Jy sample. We present the list of 56 SMS4 sources that in 2022 March remain to be observed in the X-rays with narrow-field instruments, to highlight interesting sources and organize further observational campaigns to achieve complete X-ray coverage for the whole SMS4 in the forthcoming years.

Keywords: X-ray astronomy, Extragalactic radio sources, Active galaxies
Calibration of Transition-edge Sensor (TES) Bolometer Arrays with Application to CLASS. The current and future cosmic microwave background (CMB) experiments fielding kilopixel arrays of transition-edge sensor (TES) bolometers require accurate and robust gain calibration methods. We simplify and refactor the standard TES model to directly relate the detector responsivity calibration and optical time constant to the measured TES current I and the applied bias current I b. The calibration method developed for the Cosmology Large Angular Scale Surveyor (CLASS) TES bolometer arrays relies on current versus voltage (I-V) measurements acquired daily prior to CMB observations. By binning Q-band (40 GHz) I-V measurements by optical loading, we find that the gain calibration median standard error within a bin is 0.3%. We test the accuracy of this I-V bin detector calibration method by using the Moon as a photometric standard. The ratio of measured Moon amplitudes between the detector pairs sharing the same feedhorn indicates a TES calibration error of 0.5%. We also find that, for the CLASS Q-band TES array, calibrating the response of individual detectors based solely on the applied TES bias current accurately corrects TES gain variations across time but introduces a bias in the TES calibration from data counts to power units. Since the TES current bias value is set and recorded before every observation, this calibration method can always be applied to the raw TES data and is not subject to I-V data quality or processing errors.

Keywords: Early universe, CMBR detectors, Observational cosmology, Cosmic microwave background radiation
Thermodynamics of the Inner Heliosheath. We derive annual sky maps of the proton temperature in the inner heliosheath (IHS), and track their temporal evolution over the years 2009-2016 of Interstellar Boundary Explorer observations. Other associated thermodynamic parameters also determined are the density, kappa (the parameter that characterizes kappa distributions), temperature rate, polytropic index, and entropy. We exploit the theory of kappa distributions and their connection with polytropes, to (i) express a new polytropic quantity Π that remains invariant along streamlines where temperature and density may vary, (ii) parameterize the proton flux in terms of the Π invariant and kappa, and (iii) derive the temperature and density, respectively, from the slope and intercept of the linear relationship between kappa and logarithm of Π. We find the following thermodynamic characteristics: (1) temperature sky maps and histograms shifted to their lowest values in 2012 and their highest in 2015; (2) temperature negatively correlated with density, reflecting the subisothermal polytropic behavior; (3) temperature positively correlated with kappa, revealing characteristics of the mechanism responsible for generating kappa distributions; (4) processes in IHS are subisothermal tending toward isobaric, consistent with previously published results; (5) linear relationship between kappa and polytropic indices, revealing characteristics of the particle potential energy; and (6) entropy positively correlated with polytropic index, aligned with the underlying theory that entropy increases toward the isothermal state where the kappa distribution reduces to the Maxwell-Boltzmann description.

Keywords: Space plasmas, Heliosheath, Heliosphere
The Carnegie-Irvine Galaxy Survey. X. Bulges in Stellar Mass–based Scaling Relations. We measure optical colors for the bulges of 312 disk galaxies from the Carnegie-Irvine Galaxy Survey and convert their previously available R-band structural parameters to stellar-mass parameters. We also measure their average stellar-mass surface density in the central 1 kpc (Σ1). Comparing the mass-based Kormendy relation with the original one based on flux, we find that the majority of the classifications into classical and pseudo bulges, as well as their overall statistical properties, remain essentially unchanged. While the bulge-type classifications of the Kormendy relation are robust against stellar population effects, the mass-based classification criteria do produce better agreement between bulge structural properties and their stellar populations. Moreover, the mass-based Kormendy relation reveals a population of ultradense bulges akin to high-z compact early-type galaxies, which are otherwise hidden in the original Kormendy relation. These bulges are probably relics of spheroids assembled in the early universe, although for some we cannot rule out some contribution from secular growth. We confirm previous studies that Σ1 correlates well with bulge surface densities.

Keywords: Disk galaxies, Galaxy structure, Galaxy bulges, Galaxy photometry, Galaxy evolution, Elliptical galaxies
GST Data-processing Workflow: Image Registration and Alignment. Multiple solar instrument observation campaigns are increasingly popular among the solar physics and space science communities. Scientists organize high-resolution ground-based telescopes and spacecraft to study the evolution of the complex solar atmosphere and the origin of space weather. Image registration and coalignment between different instruments are vital for accurate data product comparison. We developed a Python language package for registration of ground-based high-resolution imaging data acquired by the Goode Solar Telescope (GST) to space-based full-disk continuum intensity data provided by the Solar Dynamics Observatory (SDO) with the scale-invariant feature transform method. The package also includes tools to align data sets obtained in different wavelengths and at different times utilizing the optical flow method. We present the image registration and coalignment workflow. The aliment accuracy of each alignment method is tested with the aid of radiative magnetohydrodynamics simulation data. We update the pointing information in GST data fits headers and generate GST and SDO imaging data products as science-ready four-dimensional (x, y, λ, t) data cubes.

Keywords: Solar chromosphere, Solar photosphere, Astronomy image processing
Uniform Recalibration of Common Spectrophotometry Standard Stars onto the CALSPEC System Using the SuperNova Integral Field Spectrograph. We calibrate spectrophotometric optical spectra of 32 stars commonly used as standard stars, referenced to 14 stars already on the Hubble Space Telescope-based CALSPEC flux system. Observations of CALSPEC and non-CALSPEC stars were obtained with the SuperNova Integral Field Spectrograph over the wavelength range 3300-9400 Å as calibration for the Nearby Supernova Factory cosmology experiment. In total, this analysis used 4289 standard-star spectra taken on photometric nights. As a modern cosmology analysis, all presubmission methodological decisions were made with the flux scale and external comparison results blinded. The large number of spectra per star allows us to treat the wavelength-by-wavelength calibration for all nights simultaneously with a Bayesian hierarchical model, thereby enabling a consistent treatment of the Type Ia supernova cosmology analysis and the calibration on which it critically relies. We determine the typical per-observation repeatability (median 14 mmag for exposures ≳5 s), the Maunakea atmospheric transmission distribution (median dispersion of 7 mmag with uncertainty 1 mmag), and the scatter internal to our CALSPEC reference stars (median of 8 mmag). We also check our standards against literature filter photometry, finding generally good agreement over the full 12 mag range. Overall, the mean of our system is calibrated to the mean of CALSPEC at the level of ~3 mmag. With our large number of observations, careful cross-checks, and 14 reference stars, our results are the best calibration yet achieved with an integral-field spectrograph, and among the best calibrated surveys.

Keywords: Spectrophotometric standards, Spectrophotometry, Flux calibration
GWFAST: A Fisher Information Matrix Python Code for Third-generation Gravitational-wave Detectors. We introduce GWFAST (https://github.com/CosmoStatGW/gwfast), a Fisher information matrix Python code that allows for easy and efficient estimation of signal-to-noise ratios and parameter measurement errors for large catalogs of resolved sources observed by networks of gravitational-wave (GW) detectors. In particular, GWFAST includes the effects of the Earth's motion during the evolution of the signal, supports parallel computation, and relies on automatic differentiation rather than on finite differences techniques, which makes possible the computation of derivatives with accuracy close to machine precision. We also release the library WF4Py (https://github.com/CosmoStatGW/WF4Py) implementing state-of-the-art GW waveforms in Python. In this paper we provide a documentation of GWFAST and WF4Py with practical examples and tests of performance and reliability. In the companion paper Iacovelli et al. we present forecasts for the detection capabilities of the second and third generation of ground-based GW detectors, obtained with GWFAST.

Keywords: Astrostatistics tools, Gravitational wave detectors, Fisher's Information, Gravitational wave sources, Gravitational wave astronomy
REST: A Java Package for Crafting Realistic Cosmic Dust Particles. The overall understanding of cosmic dust particles is mainly inferred from the different Earth-based measurements of interplanetary dust particles and space missions such as Giotto, Stardust, and Rosetta. The results from these measurements indicate the presence of a wide variety of morphologically significant dust particles. To interpret the light-scattering and thermal emission observations arising due to dust in different regions of space, it is necessary to generate computer-modeled realistic dust structures of various shapes, sizes, porosity, bulk density, aspect ratio, and material inhomogeneity. The present work introduces a Java package called Rough Ellipsoid Structure Tool (REST), which is a collection of multiple algorithms, that aims to craft realistic rough-surface cosmic dust particles from spheres, superellipsoids, and fractal aggregates depending on the measured bulk density and porosity. Initially, spheres having N  d  dipoles or lattice points are crafted by selecting random material and space seed cells to generate a strongly damaged structure, rough surface, and poked structure. Similarly, REST generates rough-surface superellipsoids and poked structure superellipsoids from initial superellipsoid structures. REST also generates rough fractal aggregates, which are fractal aggregates having rough-surface irregular grains. REST has been applied to create agglomerated debris, agglomerated debris superellipsoids, and mixed-morphology particles. Finally, the light-scattering properties of the respective applied structures are studied to ensure their applicability. REST is a flexible structure tool that shall be useful for generating various types of dust structures that can be applied to studying the physical properties of dust in different regions of space.

Keywords: Interstellar dust, Dust physics, Software available on request, Radiative transfer simulations, Interplanetary dust, Circumstellar dust