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Blazar Variability: A Study of Nonstationarity and the Flux-Rms Relation
Bhattacharyya, Joy; Ghosh, Ritesh; Chatterjee, Ritaban +1 more
We analyze X-ray light curves of the blazars Mrk 421, PKS 2155-304, and 3C 273 using observations by the Soft X-ray Telescope on board AstroSat and archival XMM-Newton data. We use light curves of length 30-90 ks from three to four epochs for all three blazars. We apply the autoregressive integrated moving average model, which indicates the variab…
Gaia-DR2 extended kinematical maps. III. Rotation curves analysis, dark matter, and MOND tests
Wang, H. -F.; López-Corredoira, M.; Chrobáková, Ž. +2 more
Context. Recent statistical deconvolution methods have produced extended kinematical maps in a range of heliocentric distances that are a factor of two to three larger than those analysed in Gaia Collaboration (2018, A&A, 616, A11) based on the same data.
Aims: In this paper, we use such maps to derive the rotation curve both in the Galac…
A search for star clusters in the outskirts of the Large Magellanic Cloud: indication of clusters in the age gap
Cignoni, M.; Tosi, M.; Ripepi, V. +7 more
The YMCA (Yes, Magellanic Clouds Again) and STEP (The SMC in Time: Evolution of a Prototype interacting late-type dwarf galaxy) projects are deep g, i photometric surveys carried out with the VLT Survey Telescope (VST) and devoted to study the outskirts of the Magellanic System. A main goal of YMCA and STEP is to identify candidate stellar cluster…
Search for Planets in Hot Jupiter Systems with Multi-Sector TESS Photometry. I. No Companions in Planetary Systems KELT-18, KELT-23, KELT-24, Qatar-8, WASP-62, WASP-100, WASP-119, and WASP-126
Maciejewski, G.
Origins of giant planets on tight orbits, so called hot Jupiters, are a long-lasting question in the planetary formation and evolution theory. The answer seems to be hidden in architectures of those systems that remain only partially understood. Using multi-sector time-series photometry from the Transiting Exoplanet Survey Satellite, we searched f…
TESS Asteroseismic Analysis of the Known Exoplanet Host Star HD 222076
Chaplin, William J.; Kane, Stephen R.; Stassun, Keivan G. +22 more
The Transiting Exoplanet Survey Satellite (TESS) is an all-sky survey mission aiming to search for exoplanets that transit bright stars. The high-quality photometric data of TESS are excellent for the asteroseismic study of solar-like stars. In this work, we present an asteroseismic analysis of the red-giant star HD 222076 hosting a long-period (2…
A Comparison of X-Ray Photon Indices among the Narrow- and Broad-line Seyfert 1 Galaxies
Rakshit, Suvendu; Dewangan, Gulab Chand; Ojha, Vineet +1 more
We present a detailed comparative systematic study using a sample of 221 narrow-line Seyfert 1 (NLSy1) galaxies in comparison to a redshift-matched sample of 154 broad-line Seyfert 1 (BLSy1) galaxies based on their observations using ROSAT and/or XMM-Newton in soft X-ray band (0.1-2.0 keV). A homogeneous analysis is carried out to estimate their s…
Three planets transiting the evolved star EPIC 249893012: a hot 8.8-M⊕ super-Earth and two warm 14.7 and 10.2-M⊕ sub-Neptunes
Kuzuhara, M.; Alonso, R.; Erikson, A. +57 more
We report the discovery of a new planetary system with three transiting planets, one super-Earth and two sub-Neptunes, that orbit EPIC 249893012, a G8 IV-V evolved star (M⋆ = 1.05 ± 0.05 M⊙, R⋆ = 1.71 ± 0.04 R⊙, Teff = 5430 ± 85 K). The star is just leaving the main sequence. We combined K2 ph…
First Solar Energetic Particles Measured on the Lunar Far-side
Wang, Yuming; Xu, Zigong; Guo, Jingnan +7 more
On 2019 May 6 the Lunar Lander Neutron & Dosimetry (LND) Experiment on board the Chang'E-4 lander on the far-side of the Moon detected its first solar energetic particle (SEP) event with proton energies up to 21 MeV. Combined proton energy spectra are studied based on the LND, SOHO/EPHIN, and ACE/EPAM measurements, which show that LND could pr…
Far-infrared Photometric Redshifts: A New Approach to a Highly Uncertain Enterprise
Casey, Caitlin M.
This paper presents a new approach to deriving far-infrared (FIR) photometric redshifts for galaxies based on their reprocessed emission from dust at rest-frame FIR through millimeter wavelengths. FIR photometric redshifts ("FIR-z") have been used over the past decade to derive redshift constraints for highly obscured galaxies that lack photometry…
Accretion History of AGNs. II. Constraints on AGN Spectral Parameters Using the Cosmic X-Ray Background
Kirkpatrick, Allison; Marchesi, Stefano; Urry, C. Megan +5 more
We constrain X-ray spectral shapes for the ensemble of active galactic nuclei (AGNs) based on the shape of the cosmic X-ray background (CXB). Specifically, we rule out regions of X-ray spectral parameter space that do not reproduce the CXB in the energy range 1-100 keV. The key X-ray spectral parameters are the photon index, Γ; the cutoff energy, …