Search Publications
The bright-star masks for the HSC-SSP survey
Oguri, Masamune; Medezinski, Elinor; Bosch, James +4 more
We present the procedure to build and validate the bright-star masks for the Hyper-Suprime-Cam Strategic Subaru Proposal (HSC-SSP) survey. To identify and mask the saturated stars in the full HSC-SSP footprint, we rely on the Gaia and Tycho-2 star catalogues. We first assemble a pure star catalogue down to GGaia < 18 after removing ∼…
Suzaku and NuSTAR X-ray spectroscopy of γ Cassiopeiae and HD 110432
Tsujimoto, Masahiro; Hayashi, Takayuki; Kitaguchi, Takao +1 more
γ Cas and its dozen analogs comprise a small but distinct class of X-ray sources. They are early Be-type stars with an exceptionally hard thermal X-ray emission. The X-ray production mechanism has been under intense debate. Two competing ideas are (i) the magnetic activities in the Be star and its disk, and (ii) the mass accretion onto the unident…
LAMOST J221750.59+210437.2: A new member of carbon-enhanced extremely metal-poor stars with excesses of Mg and Si
Honda, Satoshi; Li, Haining; Ishigaki, Miho N. +4 more
We report on the elemental abundances of the carbon-enhanced metal-poor (CEMP) star J2217+2104, discovered through our metal-poor star survey with LAMOST and Subaru. This object is a red giant and has extremely low Fe abundance ([Fe/H] = -4.0) and very large enhancement of C, N, and O with excesses of Na, Mg, Al, and Si. This star is a new example…
Membership determination of open clusters based on a spectral clustering method
Gao, Xin-Hua
We present a spectral clustering (SC) method aimed at segregating reliable members of open clusters in multi-dimensional space. The SC method is a non-parametric clustering technique that performs cluster division using eigenvectors of the similarity matrix; no prior knowledge of the clusters is required. This method is more flexible in dealing wi…
Search for companions in visual binary systems using precise radial-velocity measurements
Sato, Bun'ei; Itoh, Yoichi; Katoh, Noriyuki
The frequency of triple and quadruple systems is considered to be high in the early phase of star formation. Some multiple systems decay in the pre-main-sequence phase. The multiplicity of main-sequence stars provides clues about the evolution of binary systems. This work searched for companions of five components of visual binary systems using pr…