Abstract
A report is presented on Suzaku observations of the ultra-luminous X-ray source X-l in the starburst galaxy M 82, made three times in 2005 October for an exposure of ̃ 30 ks each. The XIS signals from a region of radius 3' around the nucleus defined a 2-10keV flux of 2.1 × 10 -11 erg s -1 cm -2 attributable to point sources. The 3.2-10keV spectrum was slightly more convex than a power-law with a photon index of 1.7. In all observations, the HXD also detected signals from M 82 up to ̃20keV, at a 12-20keV flux of 4.4 × 10 -12erg s -1 cm -2. The HXD spectrum was steeper than that of the XIS. The XIS and HXD spectra can be jointly reproduced by a cutoff power-law model, or similar curved models. Of the detected wide-band signals, 1/3 to 2/3 are attributable to X-l, while the remainder to other discrete sources in M 82. Regardless of the modeling of these contaminants, the spectrum attributable to X-1 is more curved than a power-law, with a bolometric luminosity of (1.5-3) × 10 40 erg s -1. These results are interpreted as Comptonized emission from a black hole of 100-200 solar masses, radiating roughly at the Eddington luminosity.
| Original language | English |
|---|---|
| Journal | Publications of the Astronomical Society of Japan |
| Volume | 61 |
| Issue number | SUPPL. 1 |
| Publication status | Published - 2009 |
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Keywords
- Balck hole physics
- Galaxies: Individual (M 82)
- X-rays: Stars
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
Suzaku observations of M 82 X-l : Detection of a curved hard X-Ray spectrum. / Miyawaki, Ryohei; Makishima, Kazuo; Yamada, Shin'ya; Gandhi, Poshak; Mizuno, Tsunefumi; Kubota, Aya; Tsuru, Takeshi G.; Matsumoto, Hironori.
In: Publications of the Astronomical Society of Japan, Vol. 61, No. SUPPL. 1, 2009.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Suzaku observations of M 82 X-l
T2 - Detection of a curved hard X-Ray spectrum
AU - Miyawaki, Ryohei
AU - Makishima, Kazuo
AU - Yamada, Shin'ya
AU - Gandhi, Poshak
AU - Mizuno, Tsunefumi
AU - Kubota, Aya
AU - Tsuru, Takeshi G.
AU - Matsumoto, Hironori
PY - 2009
Y1 - 2009
N2 - A report is presented on Suzaku observations of the ultra-luminous X-ray source X-l in the starburst galaxy M 82, made three times in 2005 October for an exposure of ̃ 30 ks each. The XIS signals from a region of radius 3' around the nucleus defined a 2-10keV flux of 2.1 × 10 -11 erg s -1 cm -2 attributable to point sources. The 3.2-10keV spectrum was slightly more convex than a power-law with a photon index of 1.7. In all observations, the HXD also detected signals from M 82 up to ̃20keV, at a 12-20keV flux of 4.4 × 10 -12erg s -1 cm -2. The HXD spectrum was steeper than that of the XIS. The XIS and HXD spectra can be jointly reproduced by a cutoff power-law model, or similar curved models. Of the detected wide-band signals, 1/3 to 2/3 are attributable to X-l, while the remainder to other discrete sources in M 82. Regardless of the modeling of these contaminants, the spectrum attributable to X-1 is more curved than a power-law, with a bolometric luminosity of (1.5-3) × 10 40 erg s -1. These results are interpreted as Comptonized emission from a black hole of 100-200 solar masses, radiating roughly at the Eddington luminosity.
AB - A report is presented on Suzaku observations of the ultra-luminous X-ray source X-l in the starburst galaxy M 82, made three times in 2005 October for an exposure of ̃ 30 ks each. The XIS signals from a region of radius 3' around the nucleus defined a 2-10keV flux of 2.1 × 10 -11 erg s -1 cm -2 attributable to point sources. The 3.2-10keV spectrum was slightly more convex than a power-law with a photon index of 1.7. In all observations, the HXD also detected signals from M 82 up to ̃20keV, at a 12-20keV flux of 4.4 × 10 -12erg s -1 cm -2. The HXD spectrum was steeper than that of the XIS. The XIS and HXD spectra can be jointly reproduced by a cutoff power-law model, or similar curved models. Of the detected wide-band signals, 1/3 to 2/3 are attributable to X-l, while the remainder to other discrete sources in M 82. Regardless of the modeling of these contaminants, the spectrum attributable to X-1 is more curved than a power-law, with a bolometric luminosity of (1.5-3) × 10 40 erg s -1. These results are interpreted as Comptonized emission from a black hole of 100-200 solar masses, radiating roughly at the Eddington luminosity.
KW - Balck hole physics
KW - Galaxies: Individual (M 82)
KW - X-rays: Stars
UR - http://www.scopus.com/inward/record.url?scp=65349178903&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=65349178903&partnerID=8YFLogxK
M3 - Article
VL - 61
JO - Publication of the Astronomical Society of Japan
JF - Publication of the Astronomical Society of Japan
SN - 0004-6264
IS - SUPPL. 1
ER -