Spectral study of ultra-luminous compact X-ray sources with XMM-NEWTON and CHANDRA

R. Miyawaki, M. Sogiho, A. Kubota, K. Makishima, M. Namiki, T. Tanaka, N. Tsunoda

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


Using the ASCA, XMM-Newton, and Chandra data, luminosity-dependent spectral changes of the ultra-luminous X-ray source (ULX) M 81 X-9 were studied. When the luminosity was below a threshold of ∼1.5×1040 erg s-1, the source consistently exhibited power-law spectra. In contrast, the spectra at higher luminosities were more convex, favoring a multi-color-disk modeling. A p-free disk model with p ∼ 0.6 gave a still better fit to the high-luminosity spectra of M81 X-9, suggesting the presence of a slim disk. Another ULX, NGC 1313 Source B, also showed a similar luminosity-dependent spectral change. These results agree with the ASCA report on the two ULXs in IC 342 (Kubota et al., 2001).

Original languageEnglish
Title of host publicationX-ray Universe 2005
Number of pages6
Publication statusPublished - 2006
Externally publishedYes
EventX-ray Universe 2005 - Madrid, Spain
Duration: 2005 Sept 262005 Sept 30

Publication series

NameEuropean Space Agency, (Special Publication) ESA SP
ISSN (Print)0379-6566


ConferenceX-ray Universe 2005


  • Galaxies: individual (M 81 / NGC 1313)
  • X-rays: galaxies

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science


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