Spectral transitions of an ultraluminous X-ray source, NGC 2403 Source 3 (2008)
Isobe, Naoki, Makishima, Kazuo, Takahashi, Hiromitsu, Mizuno, Tsunefumi, Miyawaki, Ryouhei, Gandhi, Poshak, ...
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 with a multi-color...
Suzaku Observations of M82 X-1 : Detection of a Curved Hard X-ray Spectrum (2008)
Miyawaki, Ryohei, Makishima, Kazuo, Yamada, Shinya, Gandhi, Poshak, Mizuno, Tsunefumi, Kubota, Aya, ...
A report is presented on Suzaku observations of the ultra-luminous X-ray source X-1 in the starburst galaxy M82, made three time in 2005 October for an exposure of ~ 30 ks each. The XIS signals from...
Suzaku Results on Cygnus X-1 in the Low/Hard State (2008)
Makishima, Kazuo, Takahashi, Hiromitsu, Yamada, Shin'ya, Done, Chris, Kubota, Aya, Dotani, Tadayasu, ...
The black-hole binary Cygnus X-1 was observed for 17 ks with the Suzaku X-ray observatory in 2005 October, while it was in a low/hard state with a 0.7-300 keV luminosity of 4.6 x 10^37 erg/s. The XIS...
Discovery of a bright transient ultraluminous X-ray source Suzaku J1305-4931 in NGC 4945 (2007)
Isobe, Naoki, Kubota, Aya, Makishima, Kazuo, Gandhi, Poshak, Griffiths, Richard E., Dewangan, Gulab C., ...
This paper reports the discovery of a bright X-ray transient source, Suzaku J1305-4913, in the south-west arm of the nearby Seyfert II galaxy NGC 4945. It was detected at a 0.5 -- 10 keV flux of $2.2...
Modelling the behaviour of accretion flows in X-ray binaries (2007)
Done, Chris, Gierlinski, Marek, Kubota, Aya
(abridged) We review how the recent increase in X-ray and radio data from black hole and neutron star binaries can be merged together with theoretical advances to give a coherent picture of the...
Low/Hard State Spectra of GRO J1655-40 Observed with Suzaku (2007)
Takahashi, Hiromitsu, Fukazawa, Yasushi, Mizuno, Tsunefumi, Hirasawa, Ayumi, Kitamoto, Shunji, Sudoh, Keisuke, ...
The Galactic black-hole binary GRO J1655$-$40 was observed with Suzaku on 2005 September 22--23, for a net exposure of 35 ks with the X-ray Imaging Spectrometer (XIS) and 20 ks with the Hard X-ray...
The X-ray observatory Suzaku (2007)
Mitsuda, Kazuhisa, Bautz, Mark, Inoue, Hajime, Kelley, Richard L., Koyama, Katsuji, Kunieda, Hideyo, ...
Suzaku observation of 1H0707-495: puzzling spectral drop around 7 keV (2007)
Hayashida, Kiyoshi, Anabuki, Naohisa, Gallo, Luigi, Iwasawa, Kazushi, Tanaka, Yasuo, Miniutti, Giovanni, ...
Kubota, Aya, Dotani, Tadayasu, Cottam, Jean, Kotani, Taro, Done, Chris, Ueda, Yoshihiro, ...
We present the results of six Suzaku observations of the recurrent black hole transient 4U1630-472 during its decline from outburst from February 8 to March 23 in 2006. All observations show the...
Tsunoda, Naoko, Kubota, Aya, Namiki, Masaaki, Sugiho, Masahiko, Kawabata, Kiyoshi, Makishima, Kazuo
We report on the results of detailed spectral studies of the ultra-luminous X-ray source (ULX), M81 X-9 (Holmberg IX X-1), made with XMM-Newton on 2001 April 22 and with ASCA on 1999 April 6. On both...
(truncated version) The X-ray spectra of Galactic binary systems in the very high state show both strong disk emission and a strong, steep tail to high energies. We use simultaneous optical-ASCA-RXTE...
Three Spectral States of the Disk X-Ray Emission of the Black-Hole Candidate 4U 1630-47 (2005)
Abe, Yukiko, Fukazawa, Yasushi, Kubota, Aya, Kasama, Daisuke, Makishima, Kazuo
We studied a time history of X-ray spectral states of a black-hole candidate, 4U 1630-47, utilizing data from a number of monitoring observations with the Rossi X-Ray Timing Explorer over 1996--2004....
Observational studies of stellar black hole binaries and ULXs (2005)
We outline a framework for understanding the X-ray spectra of high mass accretion rate stellar black holes based on X-ray data from RXTE and ASCA. Three spectral regimes can be separated out by the...
Kubota, Aya, Ebisawa, Ken, Makishima, Kazuo, Nakazawa, Kazuhiro
X-ray spectra of black hole binaries(BHBs) in the high/soft state were studied comprehensively by using ASCA GIS data, and partially RXTE PCA data. A mathematical disk model was applied to several...
Murashima, Mio, Kubota, Aya, Makishima, Kazuo, Kokubun, Motohide, Hong, Soojing, Negoro, Hitoshi
An analysis was made of 0.3-15 keV X-ray spectra of a Narrow-Line Seyfert 1 Galaxy, Ton S180, using archival data from ASCA, RXTE, and XMM-Newton. At energies above 2.5 keV, a power-law with a photon...
The 1998 outburst of the bright Galactic black hole binary system XTE J1550-564 was used to constrain the accretion disc structure in the strongly Comptonised very high state spectra. These data show...
The present paper describes the analysis of multiple RXTE/PCA data of the black hole binary with superluminal jet, XTE J1550-564, acquired during its 1999--2000 outburst. The X-ray spectra show...
Ebisawa, Ken, Zycki, Piotr, Kubota, Aya, Mizuno, Tsunefumi, Watarai, Ken-ya
Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and Galactic superluminal jet sources share the common spectral characteristic that they have unusually high disk temperatures...
Kubota, Aya, Done, Chris, Makishima, Kazuo
The ultraluminous compact X-ray sources (ULXs) generally show a curving spectrum in the 0.7--10 keV ASCA bandpass, which looks like a high temperature analogue of the disk dominated high/soft state...
Ebisawa, Ken, Kubota, Aya, Mizuno, Tsunefumi, Zycki, Piotr
The Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and the Galactic super-luminal jet sources share the common spectral characteristic that they have extremely high disk...
Fukazawa, Yasushi, Iyomoto, Naoko, Kubota, Aya, Matsumoto, Yukari, Makishima, Kazuo
We observed the nearby galaxy M~51 (NGC 5194) with BeppoSAX. The X-ray properties of the nucleus below 10 keV are almost the same as the ASCA results regarding the hard component and the neutral Fe...
Observational Evidence for Strong Disk Comptonization in GRO J1655-40 (2001)
Kubota, Aya, Makishima, Kazuo, Ebisawa, Ken
Analysis was made of the multiple XTE/PCA data on the promised black hole candidate with superluminal jet, GRO J1655-40, acquired during its 1996--1997 outburst. The X-ray spectra can be adequately...
"December 2001."
Discovery of Spectral Transitions from Two Ultra-Luminous Compact X-Ray Sources in Ic342 (2000)
Kubota, Aya, Mizuno, Tsunefumi, Makishima, Kazuo, Fukazawa, Yasushi, Kotoku, Jun'ichi, Ohnishi, Tomohisa, ...
Two {\it ASCA} observations were made of two ultra-luminous compact X-ray sources (ULXs), Source 1 and Source 2, in the spiral galaxy IC 342. In the 1993 observation, Source 2 showed a 0.5--10 keV...
The Nature of Ultra-Luminous Compact X-Ray Sources in Nearby Spiral Galaxies (2000)
Makishima, Kazuo, Kubota, Aya, Mizuno, Tsunefumi, Ohnishi, Tomohisa, Tashiro, Makoto, Aruga, Yoichi, ...
Studies were made of ASCA spectra of seven ultra-luminous compact X-ray sources (ULXs) in nearby spiral galaxies; M33 X-8 (Takano et al. 1994), M81 X-6 (Fabbiano 1988b; Kohmura et al. 1994; Uno...
Mizuno, Tsunefumi, Ohnishi, Tomohisa, Kubota, Aya, Makishima, Kazuo, Tashiro, Makoto
The edge-on spiral galaxy NGC 4565 was observed for $\sim$ 35 ks with ASCA in the 0.5-10 keV energy band. The X-ray emission was dominated by two bright sources, which can be identified with two...
Thesis (M.S.)--Columbia University, 1998.