Search Publications
Deep Extragalactic Surveys around the Ecliptic Poles with AKARI (ASTRO-F)
Nakagawa, Takao; Shirahata, Mai; Oyabu, Shinki +26 more
AKARI (formerly ASTRO-F) is an infrared space telescope designed for an all-sky survey at 10-180 µm, and deep pointed surveys of selected areas at 2-180 µm. The deep pointed surveys with AKARI will significantly advance our understanding of galaxy evolution, the structure formation of the universe, the nature of buried AGNs, and the co…
Do Ultraluminous X-Ray Sources Really Contain Intermediate-Mass Black Holes?
Ebisawa, Ken; Mineshige, Shin; Kawaguchi, Toshihiro +1 more
An open question remains whether Ultraluminous X-ray Sources (ULXs) really contain intermediate-mass black holes (IMBHs). We carefully investigated the XMM-Newton EPIC spectra of four ULXs that were claimed to be strong candidates of IMBHs by several authors. We first tried fitting by the standard spectral model of disk blackbody (DBB) + power-law…
MOIRCS Deep Survey. I: DRG Number Counts
Ouchi, Masami; Tanaka, Ichi; Yamada, Toru +11 more
We use very deep near-infrared imaging data taken with Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru Telescope to investigate the number counts of Distant Red Galaxies (DRGs). We have observed a 4x7 arcmin^2 field in the Great Observatories Origins Deep Survey North (GOODS-N), and our data reach J=24.6 and K=23.2 (5sigma, Ve…
Milliarcsecond-Scale Spectral Properties and Jet Motions in M 87
Dodson, Richard; Edwards, Philip G.; Hirabayashi, Hisashi
We have combined high resolution VLBI Space Observatory Programme (VSOP) data at 1.6 and 4.8GHz with Very Long Baseline Array (VLBA) data at higher frequencies and with similar resolutions to study the spectral properties of the core of M 87 with milliarcsec resolution. The VSOP data allows a more accurate measurement of the turnover frequency, an…
Detailed XMM-Newton Observation of the Cluster of Galaxies Abell 1060
Ishida, Manabu; Hoshino, Akio; Ohashi, Takaya +3 more
We present results from an XMM-Newton observation of the non-cooling flow cluster Abell 1060. The large effective area of XMM-Newton enabled us to investigate the nature of this cluster in unprecedented detail. >From the observed surface brightness distribution, we found that the gravitational mass distribution is well described by the Navarro-…
Chandra and XMM-Newton Observations of a Group of Galaxies, HCG 62
Fukazawa, Yasushi; Ohashi, Takaya; Yamasaki, Noriko Y. +4 more
We present results from Chandra and XMM-Newton observations of a bright group of galaxies, HCG 62. There are two cavities at about 30'' northeast and 20''southwest of the central galaxy in the Chandra image. The energy spectrum shows no significant change in the cavity compared with that in the surrounding region. The radial X-ray profile is descr…
The Virgo High-Resolution CO Survey: VI. Gas Dynamics and Star Formation along the Bar in NGC 4303
Koda, Jin; Sofue, Yoshiaki
We present CO interferometer observations of the barred galaxy NGC 4303 (M 61). This galaxy has a strong gas concentration at the central region and prominent offset ridges at the leading sides of the bar. Sharp velocity gradients are apparent across the ridges. The brightness temperature in the ridges is low, indicating the existence of unresolve…
Detailed Spectral Study of an Ultra-Luminous Compact X-Ray Source, M81 X-9, in the Disk-Dominated State
Makishima, Kazuo; Tsunoda, Naoko; Kubota, Aya +3 more
We report on the results of detailed spectral studies of an ultra-luminous X-ray source (ULX), M81 X-9 (Holmberg IX X-1), conducted with XMM-Newton on 2001 April 22 and with ASCA on 1999 April 6. On both occasions, the source showed an unabsorbed 0.5-10keV luminosity of ∼2 × 1040erg s-1 (assuming a distance of 3.4Mpc) and a s…
Non-Uniform Temperature Distribution in the Galaxy Clusters 2A 0335+096 and Abell 496 Observed by XMM-Newton
Kunieda, Hideyo; Furuzawa, Akihiro; Tawara, Yuzuru +2 more
We present the XMM-Newton results of the galaxy clusters 2A 0335+096 and A496. From an investigation of 2-dimensional ICM profiles, we obtained new features related to dynamical activities in the ICM. In 2A 0335+096, we found a spiral cool tail around the central cold core, which is trailing from the opposite side of the cold front observed by Cha…
New Corroborative Evidence for the Overdensity of Galaxies around the Radio-Loud Quasar SDSS J0836+0054 at z = 5.8
Nagao, Tohru; Taniguchi, Yoshiaki; Ajiki, Masaru +8 more
Recently, Zheng et al. (2006) found evidence for an overdensity of galaxies around a radio-loud quasar, SDSS J0836+0054, at z = 5.8 (a 5 arcmin² field). We examined our deep optical imaging data (B, V, r', i', z', and NB816) taken with the Suprime-Cam on the Subaru Telescope. The NB816 narrow-band filter (λc = 815 and Δλ = 12nm) is suit…