A possible x-ray periodicity at several tens of hours of an ultraluminous compact x-ray source in IC 342

M. Sugiho, J. Kotoku, K. Makishima, A. Kubota, T. Mizuno, Y. Fukazawa, M. Tashiro

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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 languageEnglish
Pages (from-to)L73-L76
JournalAstrophysical Journal
Volume561
Issue number1 PART 2
DOIs
Publication statusPublished - 2001 Nov 1

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Keywords

  • Black hole physics
  • Galaxies: spiral
  • X-rays: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Sugiho, M., Kotoku, J., Makishima, K., Kubota, A., Mizuno, T., Fukazawa, Y., & Tashiro, M. (2001). A possible x-ray periodicity at several tens of hours of an ultraluminous compact x-ray source in IC 342. Astrophysical Journal, 561(1 PART 2), L73-L76. https://doi.org/10.1086/324456