Search Publications
Deep 15µm AKARI Observations in the CDFS: Estimating Dust Luminosities for a MIR-Selected Sample and for Lyman Break Galaxies and the Evolution of Ldust/LUV with the Redshift
Buat, Véronique; Burgarella, Denis; Pearson, Chris +2 more
Deep observations of the Chandra Deep Field South have been secured at 15µm with AKARI/IRC infrared space telescope. From these observations, we define a sample of mid infrared-selected galaxies at 15µm and we also obtain 15µm flux densities for a sample of Lyman Break Galaxies at z ∼ 1 already observed at 24µm with Spitzer…
Spectral Transitions of an Ultraluminous X-Ray Source, NGC 2403 Source 3
Isobe, Naoki; Gandhi, Poshak; Makishima, Kazuo +8 more
A Suzaku observation of an ultraluminous X-ray source, NGC 2403 Source 3, performed on 2006 March 16-17, is reported. The Suzaku XIS spectrum of Source 3 was described as multi-color black-body-like emission from an optically thick accretion disk. The innermost disk temperature and radius were measured to be Tin = 1.08-0.03
Search for Remnant Clouds Associated with the TW Hya Association
Tachihara, Kengo; Fukui, Yasuo; Neuhäuser, Ralph
We report on a search for the parental molecular clouds of the TW Hya association (TWA), using CO emission and NaI absorption lines. TWA is the nearest young (∼50pc; ∼10Myr) stellar association; yet in spite of its youth there has been no detection of any associated natal molecular gas, as is the case with other typical young clusters. Using infra…
Magnetic Structure of Umbral Dots Observed with the Hinode Solar Optical Telescope
Ichimoto, Kiyoshi; Katsukawa, Yukio; Kitai, Reizaburo +1 more
A high-resolution, seeing-free spectroscopic observation of a decaying sunspot was made with the Solar Optical Telescope aboard the Hinode satellite. The target was NOAA 10944, located in the west side of the solar surface from 2007 March 2 to March 4. The umbra included many umbral dots (UDs) with a size of ∼300 km in continuum light. We report o…
The Origin of an Extended X-Ray Emission Apparently Associated with the Globular Cluster 47 Tucanae
Makishima, Kazuo; Nakazawa, Kazuhiro; Yuasa, Takayuki
Using the Suzaku X-ray Imaging Spectrometer, we performed a 130 ks observation of an extended X-ray emission, which was shown by ROSAT and Chandra observations to apparently associate with the globular cluster 47 Tucanae. The obtained 0.5-6 keV spectrum was successfully fitted with a redshifted thin thermal plasma emission model whose temperature …
Another Abundance Inhomogeneity in the South East Limb of the Cygnus Loop
Katsuda, Satoru; Uchida, Hiroyuki; Mori, Koji +2 more
We observed the south east (SE) limb of the Cygnus Loop with Suzaku. Our spatially-resolved spectroscopic study shows that a one-kTe non-equilibrium ionization model represents our spectra fairly well. We find that the metal abundances obtained are all depleted relative to the solar values with a positional dependence along the radial d…
Discoveries of 3 K-Shell Lines of Iron and a Coherent Pulsation of 593s from SAX J1748.2-2808
Koyama, Katsuji; Matsumoto, Hironori; Nobukawa, Masayoshi +1 more
SAX J1748.2-2808 is a unique X-ray object with a flat spectrum and strong emission lines at 6.4--7.0keV. The Suzaku satellite resolved the emission lines into 3 K-shell lines from neutral and highly ionized irons. A clear coherent pulsation with a period of 593s was found from the Suzaku and XMM-Newton archives. These facts favor that SAX J1748.2-…
Broad-Band Spectrum of the Black Hole Candidate IGR J17497-2821 Studied with Suzaku
Dotani, Tadayasu; Yamaoka, Kazutaka; Kokubun, Motohide +9 more
The broad-band 1--300keV Suzaku spectrum of IGR J17497-2821, the X-ray transient discovered by INTEGRAL in 2006 September, is presented. Suzaku observed IGR J17497-2821 on September 25, eight days after its discovery, for a net exposure of about 53 ks. During the Suzaku observation, IGR J17497-2821 is very bright, 2 × 1037erg s-1
X-Ray Studies of HESS J1837-069 with Suzaku and ASCA: a VHE Gamma-Ray Source Originated from the Pulsar Wind Nebula
Dotani, Tadayasu; Ebisawa, Ken; Bamba, Aya +1 more
We present ASCA and Suzaku studies of the TeV source HESS J1837-069, which has not been identified in other wavelengths. We confirm the presence of two X-ray sources in the Suzaku XIS image, AX J1838.0-0655 and AX J1837.3-0652, near both ends of the elongated TeV emission region. The XIS spectra of the two sources were reproduced by an absorbed po…
Particle Propagation in the Galactic Center and Spatial Distribution of Non-Thermal X-Rays
Maeda, Yoshitomo; Kokubun, Motohide; Nakazawa, Kazuhiro +9 more
We showed that if the non-thermal emission from the galactic center in the range 14-40 keV is due to inverse bremsstrahlung emission of subrelativistic protons, their interactions with hot and cold fractions of the interstellar medium are equally important. Our estimation shows that about 30% of the total non-thermal flux from the GC in the range …