Suzaku broadband observations of galactic black hole binaries

Low/hard state spectra of GRO J1655-40

Hiromitsu Takahashi, Yasushi Fukazawa, Tsunefumi Mizuno, Ayumi Hirasawa, Shunji Kitamoto, Keisuke Sudoh, Takayuki Ogita, Aya Kubota, Kazuo Makishima, Motohide Kokubun, Takeshi Itoh, Arvind N. Parmar, Tadayasu Dotani, Ken Ebisawa, Sachindra Naik, Tadayuki Takahashi, Kousuke Ohnuki, Tahir Yaqoob, Lorella Angelini, Yoshihiro Ueda & 6 others Kazutaka Yamaoka, Taro Kotani, Nobuyuki Kawai, Masaaki Namiki, Takayoshi Kohmura, Hitoshi Negoro

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The Galactic black-hole binary GRO J1655-40 was observed with Suzaku on 2005 September 22-23, for a gross time span of ∼1 day.The source was detected over a wide and continuous energy range of 0.7-300 keV, with an intensity of ∼50 mCrab in the 1.5-12 keV band. At an assumed distance of 3.2 kpc, the 0.7-300 keV luminosity is calculated to be ∼ 4.4 × 10 36 ergs s -1. The source was in a typical low/hard state, since its overall spectrum was dominated by a power-law component with a photon index of ∼1.7. The source intensity gradually decreased by 20% during the observation, involving little spectral changes above ∼3 keV. However, at softer energies, the amplitude of variability was somewhat enhanced. This indicates the presence of an independent soft component. The spectra in the hard energy band reveal a high-energy spectral cutoff, with an e-folding energy of ∼200 keV which is suggested to be higher than those observed from typical black hole binaries in the low/hard state.

Original languageEnglish
Title of host publicationEuropean Space Agency, (Special Publication) ESA SP
Pages325-332
Number of pages8
Edition622 SP
Publication statusPublished - 2006 Jul
Externally publishedYes
Event6th Integral Workshop - The Obscured Universe - Moscow, Russian Federation
Duration: 2006 Jul 22006 Jul 8

Other

Other6th Integral Workshop - The Obscured Universe
CountryRussian Federation
CityMoscow
Period06/7/206/7/8

Fingerprint

Band structure
Luminance
Photons

Keywords

  • Accretion disks
  • Black hole physics
  • Stars: individual (GRO J1655-40)
  • X-ray: binaries

ASJC Scopus subject areas

  • Aerospace Engineering

Cite this

Takahashi, H., Fukazawa, Y., Mizuno, T., Hirasawa, A., Kitamoto, S., Sudoh, K., ... Negoro, H. (2006). Suzaku broadband observations of galactic black hole binaries: Low/hard state spectra of GRO J1655-40. In European Space Agency, (Special Publication) ESA SP (622 SP ed., pp. 325-332)

Suzaku broadband observations of galactic black hole binaries : Low/hard state spectra of GRO J1655-40. / Takahashi, Hiromitsu; Fukazawa, Yasushi; Mizuno, Tsunefumi; Hirasawa, Ayumi; Kitamoto, Shunji; Sudoh, Keisuke; Ogita, Takayuki; Kubota, Aya; Makishima, Kazuo; Kokubun, Motohide; Itoh, Takeshi; Parmar, Arvind N.; Dotani, Tadayasu; Ebisawa, Ken; Naik, Sachindra; Takahashi, Tadayuki; Ohnuki, Kousuke; Yaqoob, Tahir; Angelini, Lorella; Ueda, Yoshihiro; Yamaoka, Kazutaka; Kotani, Taro; Kawai, Nobuyuki; Namiki, Masaaki; Kohmura, Takayoshi; Negoro, Hitoshi.

European Space Agency, (Special Publication) ESA SP. 622 SP. ed. 2006. p. 325-332.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Takahashi, H, Fukazawa, Y, Mizuno, T, Hirasawa, A, Kitamoto, S, Sudoh, K, Ogita, T, Kubota, A, Makishima, K, Kokubun, M, Itoh, T, Parmar, AN, Dotani, T, Ebisawa, K, Naik, S, Takahashi, T, Ohnuki, K, Yaqoob, T, Angelini, L, Ueda, Y, Yamaoka, K, Kotani, T, Kawai, N, Namiki, M, Kohmura, T & Negoro, H 2006, Suzaku broadband observations of galactic black hole binaries: Low/hard state spectra of GRO J1655-40. in European Space Agency, (Special Publication) ESA SP. 622 SP edn, pp. 325-332, 6th Integral Workshop - The Obscured Universe, Moscow, Russian Federation, 06/7/2.
Takahashi H, Fukazawa Y, Mizuno T, Hirasawa A, Kitamoto S, Sudoh K et al. Suzaku broadband observations of galactic black hole binaries: Low/hard state spectra of GRO J1655-40. In European Space Agency, (Special Publication) ESA SP. 622 SP ed. 2006. p. 325-332
Takahashi, Hiromitsu ; Fukazawa, Yasushi ; Mizuno, Tsunefumi ; Hirasawa, Ayumi ; Kitamoto, Shunji ; Sudoh, Keisuke ; Ogita, Takayuki ; Kubota, Aya ; Makishima, Kazuo ; Kokubun, Motohide ; Itoh, Takeshi ; Parmar, Arvind N. ; Dotani, Tadayasu ; Ebisawa, Ken ; Naik, Sachindra ; Takahashi, Tadayuki ; Ohnuki, Kousuke ; Yaqoob, Tahir ; Angelini, Lorella ; Ueda, Yoshihiro ; Yamaoka, Kazutaka ; Kotani, Taro ; Kawai, Nobuyuki ; Namiki, Masaaki ; Kohmura, Takayoshi ; Negoro, Hitoshi. / Suzaku broadband observations of galactic black hole binaries : Low/hard state spectra of GRO J1655-40. European Space Agency, (Special Publication) ESA SP. 622 SP. ed. 2006. pp. 325-332
@inproceedings{dc455ba71760441bbff69f51bc17e36b,
title = "Suzaku broadband observations of galactic black hole binaries: Low/hard state spectra of GRO J1655-40",
abstract = "The Galactic black-hole binary GRO J1655-40 was observed with Suzaku on 2005 September 22-23, for a gross time span of ∼1 day.The source was detected over a wide and continuous energy range of 0.7-300 keV, with an intensity of ∼50 mCrab in the 1.5-12 keV band. At an assumed distance of 3.2 kpc, the 0.7-300 keV luminosity is calculated to be ∼ 4.4 × 10 36 ergs s -1. The source was in a typical low/hard state, since its overall spectrum was dominated by a power-law component with a photon index of ∼1.7. The source intensity gradually decreased by 20{\%} during the observation, involving little spectral changes above ∼3 keV. However, at softer energies, the amplitude of variability was somewhat enhanced. This indicates the presence of an independent soft component. The spectra in the hard energy band reveal a high-energy spectral cutoff, with an e-folding energy of ∼200 keV which is suggested to be higher than those observed from typical black hole binaries in the low/hard state.",
keywords = "Accretion disks, Black hole physics, Stars: individual (GRO J1655-40), X-ray: binaries",
author = "Hiromitsu Takahashi and Yasushi Fukazawa and Tsunefumi Mizuno and Ayumi Hirasawa and Shunji Kitamoto and Keisuke Sudoh and Takayuki Ogita and Aya Kubota and Kazuo Makishima and Motohide Kokubun and Takeshi Itoh and Parmar, {Arvind N.} and Tadayasu Dotani and Ken Ebisawa and Sachindra Naik and Tadayuki Takahashi and Kousuke Ohnuki and Tahir Yaqoob and Lorella Angelini and Yoshihiro Ueda and Kazutaka Yamaoka and Taro Kotani and Nobuyuki Kawai and Masaaki Namiki and Takayoshi Kohmura and Hitoshi Negoro",
year = "2006",
month = "7",
language = "English",
pages = "325--332",
booktitle = "European Space Agency, (Special Publication) ESA SP",
edition = "622 SP",

}

TY - GEN

T1 - Suzaku broadband observations of galactic black hole binaries

T2 - Low/hard state spectra of GRO J1655-40

AU - Takahashi, Hiromitsu

AU - Fukazawa, Yasushi

AU - Mizuno, Tsunefumi

AU - Hirasawa, Ayumi

AU - Kitamoto, Shunji

AU - Sudoh, Keisuke

AU - Ogita, Takayuki

AU - Kubota, Aya

AU - Makishima, Kazuo

AU - Kokubun, Motohide

AU - Itoh, Takeshi

AU - Parmar, Arvind N.

AU - Dotani, Tadayasu

AU - Ebisawa, Ken

AU - Naik, Sachindra

AU - Takahashi, Tadayuki

AU - Ohnuki, Kousuke

AU - Yaqoob, Tahir

AU - Angelini, Lorella

AU - Ueda, Yoshihiro

AU - Yamaoka, Kazutaka

AU - Kotani, Taro

AU - Kawai, Nobuyuki

AU - Namiki, Masaaki

AU - Kohmura, Takayoshi

AU - Negoro, Hitoshi

PY - 2006/7

Y1 - 2006/7

N2 - The Galactic black-hole binary GRO J1655-40 was observed with Suzaku on 2005 September 22-23, for a gross time span of ∼1 day.The source was detected over a wide and continuous energy range of 0.7-300 keV, with an intensity of ∼50 mCrab in the 1.5-12 keV band. At an assumed distance of 3.2 kpc, the 0.7-300 keV luminosity is calculated to be ∼ 4.4 × 10 36 ergs s -1. The source was in a typical low/hard state, since its overall spectrum was dominated by a power-law component with a photon index of ∼1.7. The source intensity gradually decreased by 20% during the observation, involving little spectral changes above ∼3 keV. However, at softer energies, the amplitude of variability was somewhat enhanced. This indicates the presence of an independent soft component. The spectra in the hard energy band reveal a high-energy spectral cutoff, with an e-folding energy of ∼200 keV which is suggested to be higher than those observed from typical black hole binaries in the low/hard state.

AB - The Galactic black-hole binary GRO J1655-40 was observed with Suzaku on 2005 September 22-23, for a gross time span of ∼1 day.The source was detected over a wide and continuous energy range of 0.7-300 keV, with an intensity of ∼50 mCrab in the 1.5-12 keV band. At an assumed distance of 3.2 kpc, the 0.7-300 keV luminosity is calculated to be ∼ 4.4 × 10 36 ergs s -1. The source was in a typical low/hard state, since its overall spectrum was dominated by a power-law component with a photon index of ∼1.7. The source intensity gradually decreased by 20% during the observation, involving little spectral changes above ∼3 keV. However, at softer energies, the amplitude of variability was somewhat enhanced. This indicates the presence of an independent soft component. The spectra in the hard energy band reveal a high-energy spectral cutoff, with an e-folding energy of ∼200 keV which is suggested to be higher than those observed from typical black hole binaries in the low/hard state.

KW - Accretion disks

KW - Black hole physics

KW - Stars: individual (GRO J1655-40)

KW - X-ray: binaries

UR - http://www.scopus.com/inward/record.url?scp=45749146714&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=45749146714&partnerID=8YFLogxK

M3 - Conference contribution

SP - 325

EP - 332

BT - European Space Agency, (Special Publication) ESA SP

ER -