Sazuna/UAT_keywords huggingface dataset:
The Carnegie-Irvine Galaxy Survey. IX. Classification of Bulge Types and Statistical Properties of Pseudo Bulges. We study the statistical properties of 320 bulges of disk galaxies in the Carnegie-Irvine Galaxy Survey, using robust structural parameters of galaxies derived from image fitting. We apply the Kormendy relation to classify classical and pseudo bulges and characterize the bulge dichotomy with respect to the structural properties of the bulges and the physical properties of the host galaxies. We confirm previous findings that pseudo bulges on average have smaller Sérsic indices, lower bulge-to-total ratios, and fainter surface brightnesses than classical bulges. Our sizable sample statistically shows that pseudo bulges are more intrinsically flattened than classical bulges. Pseudo bulges are most frequent (incidence ≳80%) in late-type spirals (later than Sc). Our measurements support the picture in which pseudo bulges arose from star formation induced by inflowing gas, while classical bulges were born out of violent processes such as mergers and coalescence of clumps. We reveal differences with the literature that warrant attention: (1) the bimodal distribution of Sérsic indices presented by previous studies is not reproduced in our study; (2) classical and pseudo bulges have similar relative bulge sizes; and (3) the pseudo bulge fraction is considerably smaller in early-type disks than reported in previous studies based on one-dimensional surface brightness profile fitting. We attribute these differences to our improved image quality, more robust bulge-to-disk decomposition technique, and to the different classification criteria that we applied. Moreover, we find that barred galaxies do not host more pseudo bulges or more prominent pseudo bulges than unbarred galaxies. Various implications of these findings are discussed.

Keywords: Disk galaxies, Galaxy structure, Galaxy bulges, Galaxy photometry, Galaxy evolution, Elliptical galaxies
CME-CME Interactions as Sources of CME Geoeffectiveness: The Formation of the Complex Ejecta and Intense Geomagnetic Storm in 2017 Early September. Coronal mass ejections (CMEs) are the primary sources of intense disturbances at Earth, where their geoeffectiveness is largely determined by their dynamic pressure and internal magnetic field, which can be significantly altered during interactions with other CMEs in interplanetary space. We analyze three successive CMEs that erupted from the Sun during 2017 September 4-6, investigating the role of CME-CME interactions as a source of the associated intense geomagnetic storm (Dst_{min}=-142 nT on September 7). To quantify the impact of interactions on the (geo)effectiveness of individual CMEs, we perform global heliospheric simulations with the European Heliospheric Forecasting Information Asset (EUHFORIA) model, using observation-based initial parameters with the additional purpose of validating the predictive capabilities of the model for complex CME events. The simulations show that around 0.45 au, the shock driven by the September 6 CME started compressing a preceding magnetic ejecta formed by the merging of two CMEs launched on September 4, significantly amplifying its Bz until a maximum factor of 2.8 around 0.9 au. The following gradual conversion of magnetic energy into kinetic and thermal components reduced the Bz amplification until its almost complete disappearance around 1.8 au. We conclude that a key factor at the origin of the intense storm triggered by the 2017 September 4-6 CMEs was their arrival at Earth during the phase of maximum Bz amplification. Our analysis highlights how the amplification of the magnetic field of individual CMEs in spacetime due to interaction processes can be characterized by a growth, a maximum, and a decay phase, suggesting that the time interval between the CME eruptions and their relative speeds are critical factors in determining the resulting impact of complex CMEs at various heliocentric distances (helioeffectiveness).

Keywords: Solar-terrestrial interactions, Magnetohydrodynamics, Solar wind, Solar coronal mass ejections
Calculations of Dielectronic Recombination and Electron-impact Excitation Rate Coefficients of Highly Charged Sulfur Ions. Connected to the experiment performed at the Stockholm electron beam ion trap, a systematic relativistic configuration-interaction calculation is carried out to compare with the experimental spectra. In particular, separate rate coefficients are calculated for dominant recombination and excitation processes in the range of the impact electron energy determined by the experiment. By means of the relevant experimental parameters, the presently calculated dielectronic recombination rate coefficients for S15+ and S14+ ions and electron-impact excitation ones for S15+, S14+, and S13+ ions are employed further to synthesize overall theoretical spectra for comparison with the experimentally measured spectra. Overall, very good agreements with the experimental results are found except for one missing excitation peak around the impact electron energy 2.52 keV, which cannot be explained by the present calculations and thus remains open.

Keywords: Excitation rates, Theoretical models, Dielectronic recombination
ALMA High-frequency Long Baseline Campaign in 2017: Band-to-band Phase Referencing in Submillimeter Waves. In 2017, an Atacama Large Millimeter/submillimeter Array (ALMA) high-frequency long baseline campaign was organized to test image capabilities with baselines up to 16 km at submillimeter (submm) wavelengths. We investigated image qualities using ALMA receiver Bands 7, 8, 9, and 10 (285-875 GHz) by adopting band-to-band (B2B) phase referencing in which a phase calibrator is tracked at a lower frequency. For B2B phase referencing, it is expected that a closer phase calibrator to a target can be used, comparing to standard in-band phase referencing. In the first step, it is ensured that an instrumental phase offset difference between low- and high-frequency Bands can be removed using a differential gain calibration in which a phase calibrator is certainly detected while frequency switching. In the next step, comparative experiments are arranged to investigate the image quality between B2B and in-band phase referencing with phase calibrators at various separation angles. In the final step, we conducted long baseline imaging tests for a quasar at 289 GHz in Band 7 and 405 GHz in Band 8 and complex structure sources of HL Tau and VY CMa at ∼670 GHz in Band 9. The B2B phase referencing was successfully applied, allowing us to achieve an angular resolution of 14 × 11 and 10 × 8 mas for HL Tau and VY CMa, respectively. There is a high probability of finding a low-frequency calibrator within 5°4 in B2B phase referencing, bright enough to use an 8 s scan length combined with a 7.5 GHz bandwidth.

Keywords: Submillimeter astronomy, Long baseline interferometry, Phase error
The IAG Solar Flux Atlas: Telluric Correction with a Semiempirical Model. Observations of the Sun as a star have been key to guiding models of stellar atmospheres and additionally provide useful insights on the effects of granulation and stellar activity on radial velocity measurements. Most high-resolution solar atlases contain telluric lines that span the optical and limit the spectral regions useful for analysis. We present here a telluric-corrected solar atlas covering 0.5-1.0 μm derived from solar spectra taken with a Fourier transform spectrograph at the Institut für Astrophysik, Göttingen. This atlas is the highest-resolution spectrum with a wavelength calibration precise to ±10 m s-1 across this 500 nm spectral window. We find that the atlas matches to within 3% of the telluric-corrected Kitt Peak atlas in regions containing telluric absorption weaker than 50% in transmission. The telluric component of the spectral data is fit with a semiempirical model composed of Lorentz profiles initialized to the High-resolution Transmission Molecular Absorption Database (HITRAN) parameters for each absorption feature. Comparisons between the best-fit telluric parameters describing the Lorentz profile for each absorption feature and the original HITRAN values in general show excellent agreement considering the effects atmospheric pressure and temperature have on our final parameters. However, we identify a small subset of absorption features with larger offsets relative to the cataloged line parameters. We make our final solar atlas available online. We additionally make available the telluric spectra extracted from the data that, given the high resolution of the spectrum, would be useful for studying the time evolution of telluric line shapes and their impact on Doppler measurements.

Keywords: Earth atmosphere, The Sun, Astronomy data analysis, Computational methods, Radial velocity, Atmospheric effects
The SPTpol Extended Cluster Survey. We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 &lt; ξ &lt; 5. The confirmed sample has a median mass of M_500c∼ 4.4×1014 M_{⊙} h70-1 and a median redshift of z = 0.49, and we have identified 44 strong gravitational lenses in the sample thus far. Radio data are used to characterize contamination to the SZ signal; the median contamination for confirmed clusters is predicted to be ∼1% of the SZ signal at the ξ &gt; 4 threshold, and &lt;4% of clusters have a predicted contamination &gt;10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (λ-M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data - a difference significant at the 4σ level - with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses.

Keywords: Galaxy clusters, Strong gravitational lensing, Large-scale structure of the universe
Solar System Objects Observed with TESS—First Data Release: Bright Main-belt and Trojan Asteroids from the Southern Survey. Compared with previous space-borne surveys, the Transiting Exoplanet Survey Satellite (TESS) provides a unique and new approach to observe solar system objects. While its primary mission avoids the vicinity of the ecliptic plane by approximately six degrees, the scale height of the solar system debris disk is large enough to place various small body populations in the field of view. In this paper we present the first data release of photometric analysis of TESS observations of small solar system bodies, focusing on the bright end of the observed main-belt asteroid and Jovian Trojan populations. This data release, named TSSYS-DR1, contains 9912 light curves obtained and extracted in a homogeneous manner, and triples the number of bodies with unambiguous fundamental rotation characteristics, namely where accurate periods and amplitudes are both reported. Our catalog clearly shows that the number of bodies with long rotation periods are definitely underestimated by all previous ground-based surveys, by at least an order of magnitude.

Keywords: Observational astronomy, CCD photometry, Jupiter trojans, Period search , Main belt asteroids, Time series analysis
Swift Observations of Mrk 421 in Selected Epochs. III. Extreme X-Ray Timing/Spectral Properties and Multiwavelength Lognormality during 2015 December-2018 April. We present the results from the timing and spectral study of Mrk 421 based mainly on the Swift data in the X-ray energy range obtained during the time interval 2015 December-2018 April. The most extreme X-ray flaring activity on long-term, daily, and intraday timescales was observed during the 2 month period that started in 2017 December, when the 0.3-10 keV flux exceeded a level of 5 × 10-9 erg cm-2 s-1, recorded only twice previously. While the TeV-band and X-ray variabilities were mostly correlated, the source often varied in a complex manner in the MeV-GeV and radio-UV energy ranges, indicating that the multifrequency emission of Mrk 421 could not always be generated in a single zone. The longer-term flares at X-rays and γ-rays showed a lognormal character, possibly indicating a variability imprint of the accretion disk onto the jet. A vast majority of the 0.3-10 keV spectra were consistent with the log-parabolic model, showing relatively low spectral curvature and correlations between the different spectral parameters, predicted in the case of the first- and second-order Fermi processes. The position of the synchrotron spectral energy distribution peak showed an extreme variability on diverse timescales between the energies Ep &lt; 0.1 and &gt;15 keV, with 15% of the spectra peaking at the hard X-ray, and was related to the peak height as Sp∝ Epα with α ∼ 0.6, which is expected for the transition from Kraichnan-type turbulence into the "hard sphere" one. The 0.3-300 GeV spectra showed features of the hadronic contribution, jet-star interaction, and upscatter in the Klein-Nishina regime in different time intervals.

Keywords: Extragalactic astronomy, X-ray active galactic nuclei, Active galactic nuclei, Galaxy jets
Scaling K2. I. Revised Parameters for 222,088 K2 Stars and a K2 Planet Radius Valley at 1.9 R<SUB>⊕</SUB>. Previous measurements of stellar properties for K2 stars in the Ecliptic Plane Input Catalog largely relied on photometry and proper motion measurements, with some added information from available spectra and parallaxes. Combining Gaia DR2 distances with spectroscopic measurements of effective temperatures, surface gravities, and metallicities from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) DR5, we computed updated stellar radii and masses for 26,838 K2 stars. For 195,250 targets without a LAMOST spectrum, we derived stellar parameters using random forest regression on photometric colors trained on the LAMOST sample. In total, we measured spectral types, effective temperatures, surface gravities, metallicities, radii, and masses for 222,088 A, F, G, K, and M-type K2 stars. With these new stellar radii, we performed a simple reanalysis of 299 confirmed and 517 candidate K2 planet radii from Campaigns 1-13, elucidating a distinct planet radius valley around 1.9 R⊕, a feature thus far only conclusively identified with Kepler planets, and tentatively identified with K2 planets. These updated stellar parameters are a crucial step in the process toward computing K2 planet occurrence rates.

Keywords: Fundamental parameters of stars, Exoplanet systems, Exoplanets
Planck Galactic Cold Clumps in Two Regions: The First Quadrant and the Anticenter Direction Region. Sixty-five Planck Galactic cold clumps (PGCCs) from the first quadrant (IQuad) and 39 from the anticenter direction region (ACent) were observed in 12CO, 13CO, and C18O J = 1-0 lines using the 13.7 m telescope of the Purple Mountain Observatory. All the targets were detected in all three lines, except for 12 IQuad and 8 ACent PGCCs without C18O detection. Seventy-six and 49 velocity components were obtained in IQuad and ACent respectively; 146 cores were extracted from 76 IQuad clumps and 100 cores from 49 ACent clumps. The average Tex of IQuad cores and ACent cores is 12.4 K and 12.1 K, respectively. The average line widths of 13CO of IQuad cores and ACent cores are 1.55 km s-1 and 1.77 km s-1, respectively. Among the detected cores, 24 in IQuad and 13 in ACent have asymmetric line profiles. The small blue excesses, ∼0.03 in IQuad and 0.01 in ACent, indicate that star formation is not active in these PGCC cores. Power-law fittings of the core mass function to the high-mass end give indices of -0.57 in IQuad and -1.02 in ACent, which are flatter than the slope of the initial mass function given by Salpeter. The large turnover masses of 28 M_{⊙} for IQuad cores and 77 M_{⊙} for ACent cores suggest low star formation efficiencies in PGCCs. The correlation between virial mass and gas mass indicates that most PGCC cores in both regions are not likely pressure-confined.

Keywords: Interstellar molecules, Dark interstellar clouds, Star formation
An Extended Theoretical Scenario for Classical Cepheids. I. Modeling Galactic Cepheids in the Gaia Photometric System. We present a new extended and detailed set of models for classical Cepheid pulsators at solar chemical composition (Z = 0.02, Y = 0.28) based on a well-tested nonlinear hydrodynamical approach. In order to model the possible dependence on crucial assumptions such as the mass-luminosity relation of central helium burning intermediate-mass stars or the efficiency of superadiabatic convection, the model set was computed by varying not only the pulsation mode and the stellar mass but also the mass-luminosity relation and the mixing length parameter that is used to close the system of nonlinear hydrodynamical and convective equations. The dependence of the predicted boundaries of the instability strip as well as of both light and radial velocity curves on the assumed mass-luminosity and the efficiency of superadiabatic convection is discussed. Nonlinear period-mass-luminosity-temperature, period-radius, and period-mass-radius relations are also computed. The theoretical atlas of bolometric light curves for both the fundamental and first overtone mode has been converted in the Gaia filters G, GBP, and GBR and the corresponding mean magnitudes have been derived. Finally, the first theoretical period-luminosity-color and period-Wesenheit relations in the Gaia filters are provided and the resulting theoretical parallaxes are compared with Gaia Data Release 2 results for both fundamental and first overtone Galactic Cepheids.

Keywords: Theoretical models, Stellar pulsations, Stellar parallax, Distance indicators, Hubble constant, Cepheid variable stars, Cepheid distance
A Comprehensive Catalog of Dark Matter Halo Models for SPARC Galaxies. We present rotation curve fits to 175 late-type galaxies from the Spitzer Photometry and Accurate Rotation Curves database using seven dark matter (DM) halo profiles: pseudo-isothermal, Burkert, Navarro-Frenk-White (NFW), Einasto, Di Cintio et al. (2014, hereafter DC14), cored-NFW, and a new semi-empirical profile named Lucky13. We marginalize over the stellar mass-to-light ratio, galaxy distance, disk inclination, halo concentration, and halo mass (and an additional shape parameter for Einasto) using a Markov Chain Monte Carlo method. We find that cored halo models, such as the DC14 and Burkert profiles, generally provide better fits to rotation curves than the cuspy NFW profile. The stellar mass-halo mass relation from abundance matching is recovered by all halo profiles once imposed as a Bayesian prior, whereas the halo mass-concentration relation is not reproduced in detail by any halo model. We provide an extensive set of figures as well as best-fit parameters in machine-readable tables to facilitate model comparison and the exploration of DM halo properties.

Keywords: Galaxy dark matter halos, Galaxy formation, Dark matter distribution, Late-type galaxies, Spiral galaxies, Galaxy dynamics, Cold dark matter, Dwarf galaxies, Galaxy kinematics, Galaxy evolution, Galaxy rotation curves
Trans-Neptunian Objects Found in the First Four Years of the Dark Energy Survey. We present a catalog of 316 trans-Neptunian bodies (TNOs) detected from the first four seasons ("Y4" data) of the Dark Energy Survey (DES). The survey covers a contiguous 5000 deg2 of the southern sky in the grizY optical/NIR filter set, with a typical TNO in this part of the sky being targeted by 25-30 Y4 exposures. This paper focuses on the methods used to detect these objects from the ≈60,000 Y4 exposures, a process made challenging by the absence of the few-hour repeat observations employed by TNO-optimized surveys. Newly developed techniques include: transient/moving object detection by comparison of single-epoch catalogs to catalogs of "stacked" images; quantified astrometric error from atmospheric turbulence; new software for detecting TNO linkages in a temporally sparse transient catalog, and for estimating the rate of spurious linkages; use of faint stars to determine the detection efficiency versus magnitude in all exposures. Final validation of the reality of linked orbits uses a new "sub-threshold confirmation" test, wherein we demand the object be detectable in a stack of the exposures in which the orbit indicates an object should be present, but was not individually detected. This catalog contains all validated TNOs which were detected on ≥6 unique nights in the Y4 data, and is complete to r ≲ 23.3 mag with virtually no dependence on orbital properties for bound TNOs at distance 30 au &lt; d &lt; 2500 au. The catalog includes 245 discoveries by DES, 139 not previously published. The final DES TNO catalog is expected to yield &gt;0.3 mag more depth, and arcs of &gt;4 yr for nearly all detections.

Keywords: Astronomy data analysis, Orbit determination, Transient detection, Trans-Neptunian objects
Fermi Large Area Telescope Fourth Source Catalog. We present the fourth Fermi Large Area Telescope catalog (4FGL) of γ-ray sources. Based on the first eight years of science data from the Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1 TeV, it is the deepest yet in this energy range. Relative to the 3FGL catalog, the 4FGL catalog has twice as much exposure as well as a number of analysis improvements, including an updated model for the Galactic diffuse γ-ray emission, and two sets of light curves (one-year and two-month intervals). The 4FGL catalog includes 5064 sources above 4σ significance, for which we provide localization and spectral properties. Seventy-five sources are modeled explicitly as spatially extended, and overall, 358 sources are considered as identified based on angular extent, periodicity, or correlated variability observed at other wavelengths. For 1336 sources, we have not found plausible counterparts at other wavelengths. More than 3130 of the identified or associated sources are active galaxies of the blazar class, and 239 are pulsars.

Keywords: Gamma-ray astronomy, Sky surveys, Catalogs
Rotational Properties of Hilda Asteroids Observed by the K2 Mission. Hilda asteroids orbit at the outer edge, or just outside of the Main Belt, occupying the 2:3 mean motion resonance with Jupiter. It is known that the group shows a mixed taxonomy that suggests the mixed origin of Hilda members, having migrated to the current orbit both from the outer Main Belt and from the Trojans swarms. But there are still few observations for comparative studies to help us understand the Hilda group in deeper detail. We identified 125 individual light curves of Hilda asteroids observed by the K2 mission. We found that despite of the mixed taxonomies, the Hilda group highly resembles the Trojans in the distribution of rotation periods and amplitudes, and even the LR group (mostly C- and X-type) Hildas follow this rule. Contrary to the Main Belt, the Hilda group lacks the very fast rotators. The ratio of extremely slow rotators (P &gt; 100 hr) is a surprising 18%, which is unique in the solar system. The occurrence rate of asteroids with multiple periods (4%) and asteroids with three maxima in the light curves (5%) can be signs of a high rate of binarity, which we can estimate as 25% within the Hilda group.

Keywords: Asteroids, Solar system, Jupiter trojans, Main belt asteroids, Hilda group