Search Publications
The host galaxy of the short GRB 050709
Magnelli, B.; Palazzi, E.; Greiner, J. +10 more
The host of the short gamma-ray burst (GRB) 050709 is a morphologically disturbed low-luminous galaxy. At a redshift of z = 0.16, it belongs to one of the cosmologically nearest short-GRB hosts identified to date. Consequently, it represents a promising target for sensitive, spatially resolved observational studies. We have used the Multi Unit Spe…
Cross-match between the Latest Swift-BAT and Fermi-LAT Catalogs
Mukherjee, Reshmi; Yoneda, Hiroki; Inoue, Yoshiyuki +4 more
We report the results of a cross-match study between the hard X-ray and GeV gamma-ray catalogs, by making use of the latest 105 month Swift-Burst Alert Telescope (BAT) and 10 yr Fermi-Large Area Telescope (LAT) catalogs, respectively. The spatial cross-matching between the two catalogs results in the matching of 132 point-like sources, including ~…
New Subgrouping of Multiple Stellar Populations in NGC 2808 Based on Low-resolution Spectroscopy
Kim, Jaeyeon; Han, Sang-Il; Chung, Chul +3 more
We performed low-resolution spectroscopy for the red giant branch stars in an intriguing globular cluster (GC) NGC 2808, which hosts subpopulations with extreme helium and light-element abundances. In order to trace N, C, and Ca abundance differences among subpopulations, we measured CN, CH, and Ca II H&K spectral indices, respectively. We ide…
Probing the Nucleosynthetic Contribution of Low-metallicity, Low-mass Star Companions of CEMP Stars
Shejeelammal, J.; Goswami, Aruna
The observed abundance diversities among CEMP stars can shed light on the formation and evolution of elements in the early Galaxy. In this work, we present results obtained from a detailed abundance analysis of a sample of seven extrinsic carbon stars. The analysis is based on high-resolution spectra obtained with HCT/HESP (R~60,000) and SUBARU/HD…
Signature of a Massive Rotating Metal-poor Star Imprinted in the Phoenix Stellar Stream
Lewis, Geraint F.; Casey, Andrew R.; Erkal, Denis +13 more
The Phoenix stellar stream has a low intrinsic dispersion in velocity and metallicity that implies the progenitor was probably a low-mass globular cluster. In this work we use Magellan/Magellan Inamori Kyocera Echelle (MIKE) high-dispersion spectroscopy of eight Phoenix stream red giants to confirm this scenario. In particular, we find negligible …
The Gaia RVS benchmark stars. I. Chemical inventory of the first sample of evolved stars and its Rb NLTE investigation
Steffen, M.; Ludwig, H. -G.; Bonifacio, P. +21 more
Context. The Radial Velocity Spectrometer (RVS) on board the Gaia satellite is not provided with a wavelength calibration lamp. It uses its observations of stars with known radial velocity to derive the dispersion relation. To derive an accurate radial velocity calibration, a precise knowledge of the line spread function (LSF) of the RVS is necess…
Precise Photometric Measurements from a 1903 Photographic Plate Using a Commercial Scanner
Cerny, William; Kron, Richard G.; Martinez, Michael N. +9 more
We demonstrate the feasibility of determining magnitudes of stars on archival photographic plates using a commercially available scanner. We describe one photometric approach that could serve as a useful example for other studies. In particular, we measure and calibrate stellar magnitudes from a 1903 photographic plate from the Yerkes Observatory …
The orbits of Triton and Nereid and the pole orientation of Neptune from Voyager, Hubble Space Telescope, and Earth-based astrometry in 1847-2020
Fu, Yanning; Yuan, Ye; Chen, Jian +1 more
Context. New observations and new planetary and satellite ephemerides provide opportunities to improve the ephemerides for Triton and Nereid as well as relevant parameters. In particular, the observations include a lot of new accurate Earth-based positions reduced with Gaia astrometic catalogs and accurate positions obtained from Hubble Space Tele…
Confirming known planetary trends using a photometrically selected Kepler sample
Lin, Jane; Casagrande, Luca; Ireland, Michael J. +1 more
Statistical studies of exoplanets and the properties of their host stars have been critical to informing models of planet formation. Numerous trends have arisen in particular from the rich Kepler data set, including that exoplanets are more likely to be found around stars with a high metallicity and the presence of a 'gap' in the distribution of p…
Foreshock cavitons and spontaneous hot flow anomalies: a statistical study with a global hybrid-Vlasov simulation
Blanco-Cano, Xóchitl; Alho, Markku; Johlander, Andreas +10 more
The foreshock located upstream of Earth's bow shock hosts a wide variety of phenomena related to the reflection of solar wind particles from the bow shock and the subsequent formation of ultra-low-frequency (ULF) waves. In this work, we investigate foreshock cavitons, which are transient structures resulting from the non-linear evolution of ULF wa…