Search Publications
XMM-Newton Observation of the Cluster of Galaxies Abell 1650
Yamashita, Koujun; Takahashi, Seiji
We present the nonuniform distribution of temperature and abundance in the angular extent of 10' (1.4Mpc) in A1650 observed by XMM-Newton. Spectral analysis was carried out in 19 systematically-subdivided regions, and in 15 specified regions referred to the hardness ratio (HR) map. The value of HR, defined as the ratio of counts in the 1.6-10keV b…
Spectroscopic Determination of Stellar Atmospheric Parameters: Application to Mid-F through Early-K Dwarfs and Subgiants
Sato, Bun'ei; Kambe, Eiji; Takeda, Yoichi +2 more
Takeda et al.'s (2002, PASJ, 54, 451) method for the spectroscopic determination of stellar atmospheric parameters (Teff, logg, vt, and [Fe/H]) from the equivalent widths of Fe I and Fe II lines was applied to 32 dwarfs/subgiants of mid-F through early-K types based on high-quality echelle spectra obtained at Okayama Astrophy…
A New Empirical Method for Estimating the Far-Infrared Flux of Galaxies
Onaka, Takashi; Takeuchi, Tsutomu T.; Shibai, Hiroshi +1 more
We propose a new empirical method to estimate the total far-infrared flux of galaxies from the spectral energy distribution (SED) at wavelengths of λ <= 100 µm. It is difficult to derive the total far-infrared luminosity from only the IRAS data, though it is one of the most important properties of galaxies. Observations by Infrared Telesc…
A Multi-Band Photometric Study of Tidal Debris in a Compact Group of Galaxies: Seyfert's Sextet
Nagao, Tohru; Taniguchi, Yoshiaki; Sanders, David B. +4 more
In order to investigate the properties of the prominent tidal debris feature extending to the northeast of a compact group of galaxies, Seyfert's Sextet, we analyzed multi-band (U, B, V, VR, R, I, J, H, and K') photometric imaging data and obtained the following results: 1) The radial surface brightness distribution of this tidal debris in Seyfert…
When Did the Hubble Sequence Appear?: Morphology, Color, and Number-Density Evolution of the Galaxies in the Hubble Deep Field North
Yamada, Toru; Kajisawa, Masaru
Using the HST WFPC2/NICMOS archival data of the Hubble Deep Field North, we constructed a nearly complete sample of the MV < -20 (~ L* + 1) galaxies to z = 2, and investigate when the Hubble sequence appeared, namely, the evolution of the morphology, colors, and the comoving number density of the sample. Even if taking int…
The Spectral Energy Distributions of Blazars and the Connections among XBLs, RBLs, and OVV Quasars
Dai, Benzhong; Ma, Li; Xie, Guangzhong +2 more
In this paper, we introduce two composite spectral indices, αxox=αox-αx and αoro=αor-αo. In the composite color-color (αxoxαoro) diagram, there are three regions: (1) For XBLs and XBL-like RBLs, the values of αxox is in the range of -1.0 -0.0; (2) Fo…
Hipparcos Proper-Motion System with Respect to SPM 2.0
Zhu, Zi
On the basis of Hipparcos data, whose system is believed to be quasi-inertial to within +/-0.25 mas yr-1 and to represent an internally consistent reference frame, we carried out an analysis of the SPM 2.0 proper-motion system. Comparing the Hipparcos proper motions with those of the SPM 2.0 Catalog, which provides absolute proper motio…
NIR Narrow- and Broad-Band Study of the SSA 22 Field
Tamura, Naoyuki; Ohta, Kouji; Takata, Tadafumi +4 more
Deep narrow- and broad-band near-infrared imaging observations of the central 2'×2' region of the SSA 22 field were made with the near-infrared camera (CISCO) attached to the Subaru Telescope. Using a narrow-band filter centered at 2.033µm, [O III] λ5007 emitters at z ~ 3.06 +/- 0.02 were searched to examine star-forming activities in an ove…
Color-Magnitude Sequence in the Clusters at z ~ 1.2 near the Radio Galaxy 3C 324
Terada, Hiroshi; Usuda, Tomonori; Imanishi, Masatoshi +17 more
We have investigated the optical and near-infrared colors of K'-selected galaxies in clusters at z ~ 1.2 near to the radio galaxy 3C 324 using images obtained with the Subaru telescope and archival HST data. The distribution of colors of the galaxies in the cluster region is found to be fairly broad, and it may imply significant scatter in their s…
Galactic Rotation Derived from OB Stars Using Hipparcos Proper Motions and Radial Velocities
Uemura, Makoto; Kato, Taichi; Hirata, Ryuko +3 more
We have examined the systematic velocity field of the solar neighborhood, based on Hipparcos (HIgh Precision PARallax COllecting Satellite) proper motions and ground-based radial velocities of about 240 O-B5 stars. The distances of these stars were derived from either Hipparcos parallaxes or the SKYMAP compilation of the spectroscopic parallaxes. …