Search Publications
Multiple Stellar Populations at Less-evolved Stages-II: No Evidence of Significant Helium Spread among NGC 1846 Dwarfs
Li, Chengyuan
The detection of star-to-star chemical variations in star clusters older than 2 Gyr has changed the traditional view of star clusters as canonical examples of "simple stellar populations" into the so-called "multiple stellar populations" (MPs). Although the significance of MPs seems to correlate with cluster total mass, it seems that the presence …
Terahertz Water Masers. II. Further SOFIA/GREAT Detections Toward Circumstellar Outflows, and a Multitransition Analysis
Wyrowski, Friedrich; Menten, Karl M.; Wiesemeyer, Helmut +8 more
Following up on our discovery of terahertz water masers, reported in 2017, we report two further detections of water maser emission at frequencies above 1 THz. Using the GREAT instrument on SOFIA, we have detected emission in the 1.296411 THz 827 - 734 transition of water toward two additional oxygen-rich evolved stars, omicr…
Detailed Abundances of Planet-hosting Open Clusters. The Praesepe (Beehive) Cluster
Stassun, Keivan G.; Schuler, Simon C.; Vejar, George
It is not yet fully understood how planet formation affects the properties of host stars, in or out of a cluster; however, abundance trends can help us understand this process. We present a detailed chemical abundance analysis of six stars in Praesepe, a planet-hosting open cluster. Pr0201 is known to host a close-in (period of 4.4 days) giant pla…
Molecular Gas in a Gravitationally Lensed Galaxy Group at z = 2.9
Richard, Johan; Brammer, Gabriel; Whitaker, Katherine E. +5 more
Most molecular gas studies of z > 2.5 galaxies are of intrinsically bright objects, despite the galaxy population being primarily normal galaxies with less extreme star formation rates. Observations of normal galaxies at high redshift provide a more representative view of galaxy evolution and star formation, but such observations are challengin…
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…