Search Publications
European VLBI Network Observations of the Proposed Dual AGN SDSS J101022.95+141300.9
Paragi, Zsolt; Frey, Sándor; Gabányi, Krisztina Éva +3 more
During galaxy merger events, the supermassive black holes in the center of the galaxies may form a pair of active galactic nuclei (AGN) with kiloparsec-scale or even parsec-scale separation. Recently, optical observations revealed a promising dual-AGN candidate at the center of the galaxy SDSS J101022.95+141300.9 (hereafter J1010+1413). The presen…
Nonequilibrium Ionization Plasma during a Large Solar Limb Flare Observed by Hinode/EIS
Imada, S.
This study on plasma heating considers the time-dependent ionization process during a large solar flare on 2017 September 10, observed by Hinode/EUV Imaging Spectrometer (EIS). The observed Fe XXIV/Fe XXIII ratios increase downstream of the reconnection outflow, and they are consistent with the time-dependent ionization effect at a constant electr…
Analytic Estimates of the Achievable Precision on the Physical Properties of Transiting Planets Using Purely Empirical Measurements
Stevens, Daniel J.; Gaudi, B. Scott; Johnson, Jennifer A. +4 more
We present analytic estimates of the fractional uncertainties on the mass, radius, surface gravity, and density of a transiting planet, using only empirical or semi-empirical measurements. We first express these parameters in terms of transit photometry and radial velocity (RV) observables, as well as the stellar radius R⋆, if required.…
Star Formation Rate Function at z 4.5: An Analysis from Rest UV to Optical
Asada, Yoshihisa; Ohta, Kouji; Maeda, Fumiya
We present a star formation rate function (SFRF) at z ~ 4.5 based on photometric data from the rest UV to optical of galaxies in the CANDELS GOODS-South field using spectral energy distribution (SED) fitting. We evaluate the incompleteness of our sample and correct for it to properly compare the SFRF in this study with those estimated based on oth…
Understanding the Velocity Distribution of the Galactic Bulge with APOGEE and Gaia
Mao, Shude; Liu, Chao; Fernández-Trincado, José G. +5 more
We revisit the stellar velocity distribution in the Galactic bulge/bar region with Apache Point Observatory Galactic Evolution Experiment DR16 and Gaia DR2, focusing in particular on the possible high-velocity (HV) peaks and their physical origin. We fit the velocity distributions with two different models, namely with Gauss-Hermite polynomials an…
Non-thermal Electron Energization During the Impulsive Phase of an X9.3 Flare Revealed by Insight-HXMT
Wang, W.; Tian, H.; Zhang, S. +8 more
The X9.3 flare SOL20170906T11:55 was observed by the CsI detector aboard the first Chinese X-ray observatory Hard X-ray Modulation telescope (Insight-HXMT). Using the wavelets method, we report 22 s quasiperiodic pulsations during the impulsive phase. The spectra from 100 keV to 800 keV show the evolution with the gamma-ray flux of a power-law pho…
Hard X-Ray Emission Associated with White Dwarfs. IV. Signs of Accretion from Substellar Companions
Toalá, Jesús A.; Guerrero, Martín A.; Chu, You-Hua +3 more
With an effective temperature of ≃200,000 K, KPD 0005+5106 is one of the hottest white dwarfs (WDs). ROSAT unexpectedly detected "hard" (∼1 keV) X-rays from this apparently single WD. We have obtained Chandra observations that confirm the spatial coincidence of this hard X-ray source with KPD 0005+5106. We have also obtained XMM-Newton observation…
On the Origin of Hard X-Ray Emissions from the Behind-the-limb Flare on 2014 September 1
Kouloumvakos, Athanasios; Rouillard, Alexis P.; Warmuth, Alexander +6 more
The origin of hard X-rays and γ-rays emitted from the solar atmosphere during occulted solar flares is still debated. The hard X-ray emissions could come from flaring loop tops rising above the limb or coronal mass ejection shock waves, two by-products of energetic solar storms. For the shock scenario to work, accelerated particles must be release…
Symbiotic Stars in the Apache Point Observatory Galactic Evolution Experiment Survey: The Case of LIN 358 and SMC N73 (LIN 445a)
Pan, Kaike; Cunha, Katia; Smith, Verne V. +9 more
LIN 358 and SMC N73 are two symbiotic binaries in the halo of the Small Magellanic Cloud, each composed of a hot white dwarf accreting from a cool giant companion. In this work, we characterize these systems using a combination of spectral energy distribution (SED)-fitting to the extant photometric data spanning a broad wavelength range (X-ray/ult…
An X-Ray Study of the White Dwarf Binary AR Scorpii
Takata, J.; Kong, A. K. H.; Li, K. L. +4 more
We report a study of X-ray emission from the white dwarf/M-type star binary system AR Scorpii using archival data taken in 2016-2020. It has been known that the X-ray emission is dominated by optically thin thermal plasma emission and its flux level varies significantly over the orbital phase. The X-ray emission also contains a component that modu…