Search Publications
The new primary X-ray component confirmed in the Seyfert I galaxy IC 4329A
Makishima, Kazuo; Nakazawa, Kazuhiro; Yamada, Shin'ya +2 more
The bright and highly variable Seyfert I active galactic nucleus IC 4329A was observed with Suzaku five times in 2007 August, with intervals of ∼5 days and a net exposure of 24-31 ks each. Another longer observation was carried out in 2012 August with a net exposure of 118 ks. In the six observations, a source was detected in 2-45 keV with an aver…
Gas-to-dust ratios in massive star-forming galaxies at z ∼ 1.4
Iono, Daisuke; Hatsukade, Bunyo; Ohta, Kouji +3 more
We present results of 12CO(J = 2-1) observations toward four massive star-forming galaxies at z ∼ 1.4 with the Nobeyama 45 m radio telescope. The galaxies are detected with Spitzer/MIPS in 24 µm and Herschel/SPIRE in 250 µm and 350 µm, and they mostly reside in the main sequence. Their gas-phase metallicities derived b…
X-ray study of the supernova remnant G337.2-0.7
Koyama, Katsuji; Uchida, Hiroyuki; Nobukawa, Masayoshi +3 more
This paper reports on the Suzaku result of the Galactic supernova remnant (SNR) G337.2-0.7. The X-ray spectrum is well explained by three components in ionizing phase. One is a plasma with a low temperature kT = 0.70_{-0.03}^{+0.02}keV, solar abundances, and an ionization parameter n_et = 5.7^{+0.7}_{-0.4}× 10^{11}s cm-3. The second is …
X-ray and infrared diagnostics of nearby active galactic nuclei with MAXI and AKARI
Nakagawa, Takao; Baba, Shunsuke; Isobe, Naoki +5 more
Nearby active galactic nuclei were diagnosed in the X-ray and mid-to-far infrared wavelengths with Monitor of All-sky X-ray Image (MAXI) and the Japanese infrared observatory AKARI, respectively. One hundred of the X-ray sources listed in the second release of the MAXI all-sky X-ray source catalog are currently identified as non-blazar-type active…
Origin of the X-ray broad iron spectral feature in GRS 1915+105
Tsujimoto, Masahiro; Ebisawa, Ken; Mizumoto, Misaki +1 more
The X-ray spectrum of GRS 1915+105 is known to have a "broad iron spectral feature" in the spectral hard state. Similar spectral features are often observed in active galactic nuclei (AGNs) and other black-hole binaries (BHBs), and several models have been proposed for explaining it. In order to distinguish spectral models, time variation provides…
Image stacking analysis of SDSS galaxies with AKARI Far-Infrared Surveyor maps at 65 µm, 90 µm, and 140 µm
Doi, Yasuo; Takita, Satoshi; Ootsubo, Takafumi +4 more
We perform image stacking analysis of Sloan Digital Sky Survey (SDSS) photometric galaxies over the AKARI Far-Infrared Surveyor maps at 65 µm, 90 µm, and 140 µm. The resulting image profiles are decomposed into the central galaxy component (single term) and the nearby galaxy component (clustering term), as a function of the r-ban…
Suzaku observation of a high-entropy cluster Abell 548W
Makishima, Kazuo; Nakazawa, Kazuhiro; Gu, Liyi +4 more
Abell 548W, one of the galaxy clusters located in the Abell 548 region, has about an order of magnitude lower X-ray luminosity compared to ordinal clusters in view of the well-known intracluster medium (ICM) temperature vs. X-ray luminosity (kT-LX) relation. The cluster hosts a pair of diffuse radio sources to the northwest and north, b…
Suzaku observations of two diffuse hard X-ray source regions, G22.0+0.0 and G23.5+0.1
Bamba, Aya; Yamauchi, Shigeo; Sumita, Mayu
G22.0+0.0 and G23.5+0.1 are diffuse hard X-ray sources discovered in the ASCA Galactic Plane Survey. We present Suzaku results of spectral analysis for these sources. G22.0+0.0 is confirmed to be a largely extended emission. Its spectra were represented by a highly absorbed power-law model with a photon index of 1.7 ± 0.3 and a moderately absorbed…
Iron emission line from the spiral galaxy M 101
Yamauchi, Shigeo
Archival Suzaku data of the face-on spiral galaxy M 101 were analyzed. An intense emission line at 6.72^{+0.10}_{-0.12}keV was detected in the central region. This line is identified with a K-line from He-like iron, which indicates the existence of a thin thermal plasma with a temperature of several keV. The iron line luminosity within the central…
Suzaku confirms NGC 3660 is an unabsorbed Seyfert 2
Nandra, Kirpal; Ueda, Yoshihiro; Bianchi, Stefano +3 more
An enigmatic group of objects, unabsorbed Seyfert 2s may have intrinsically weak broad line regions, obscuration in the line of sight to the BLR but not to the X-ray corona, or so much obscuration that the X-ray continuum is completely suppressed and the observed spectrum is actually scattered into the line of sight from nearby material. NGC 3660 …