Abstract
A long (155 hr) ASCA observation was performed of two ultraluminous compact X-ray sources, source 1 and source 2, in the spiral galaxy IC 342. While source 1, which was in a hard spectral state, varied little, source 2, which was in its soft spectral state, varied significantly on a timescale of about 1 day. The rms variation amplitude amounts to 5% in the 2-10 keV band but is less than 4% in 0.7-2 keV. The variation involves statistically significant changes in the parameters describing multicolor disk blackbody emission from this source. The variation is possibly periodic, with a period of either 31 ± 2 or 41 ± 3 hr. Both are consistent with the orbital period of a semidetached binary formed by a black hole and a main-sequence star of several tens of solar masses. These results reinforce the interpretation of these X-ray objects in terms of accreting massive stellar black holes.
| Original language | English |
|---|---|
| Journal | Astrophysical Journal |
| Volume | 561 |
| Issue number | 1 PART 2 |
| DOIs | |
| Publication status | Published - 2001 Nov 1 |
| Externally published | Yes |
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Keywords
- Black hole physics
- Galaxies: spiral
- X-rays: galaxies
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
A possible x-ray periodicity at several tens of hours of an ultraluminous compact x-ray source in IC 342. / Sugiho, M.; Kotoku, J.; Makishima, K.; Kubota, Aya; Mizuno, T.; Fukazawa, Y.; Tashiro, M.
In: Astrophysical Journal, Vol. 561, No. 1 PART 2, 01.11.2001.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A possible x-ray periodicity at several tens of hours of an ultraluminous compact x-ray source in IC 342
AU - Sugiho, M.
AU - Kotoku, J.
AU - Makishima, K.
AU - Kubota, Aya
AU - Mizuno, T.
AU - Fukazawa, Y.
AU - Tashiro, M.
PY - 2001/11/1
Y1 - 2001/11/1
N2 - A long (155 hr) ASCA observation was performed of two ultraluminous compact X-ray sources, source 1 and source 2, in the spiral galaxy IC 342. While source 1, which was in a hard spectral state, varied little, source 2, which was in its soft spectral state, varied significantly on a timescale of about 1 day. The rms variation amplitude amounts to 5% in the 2-10 keV band but is less than 4% in 0.7-2 keV. The variation involves statistically significant changes in the parameters describing multicolor disk blackbody emission from this source. The variation is possibly periodic, with a period of either 31 ± 2 or 41 ± 3 hr. Both are consistent with the orbital period of a semidetached binary formed by a black hole and a main-sequence star of several tens of solar masses. These results reinforce the interpretation of these X-ray objects in terms of accreting massive stellar black holes.
AB - A long (155 hr) ASCA observation was performed of two ultraluminous compact X-ray sources, source 1 and source 2, in the spiral galaxy IC 342. While source 1, which was in a hard spectral state, varied little, source 2, which was in its soft spectral state, varied significantly on a timescale of about 1 day. The rms variation amplitude amounts to 5% in the 2-10 keV band but is less than 4% in 0.7-2 keV. The variation involves statistically significant changes in the parameters describing multicolor disk blackbody emission from this source. The variation is possibly periodic, with a period of either 31 ± 2 or 41 ± 3 hr. Both are consistent with the orbital period of a semidetached binary formed by a black hole and a main-sequence star of several tens of solar masses. These results reinforce the interpretation of these X-ray objects in terms of accreting massive stellar black holes.
KW - Black hole physics
KW - Galaxies: spiral
KW - X-rays: galaxies
UR - http://www.scopus.com/inward/record.url?scp=0035511190&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035511190&partnerID=8YFLogxK
U2 - 10.1086/324456
DO - 10.1086/324456
M3 - Article
VL - 561
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1 PART 2
ER -