ASCA observation of the X-ray transient GRS 1009-45

A. Kubota, Y. Tanaka, K. Makishima, Y. Ueda, H. Inoue, K. Yamaoka, T. Dotani

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We report on the result of the X-ray observation of X-ray Nova Velorum 1993 (GRS 1009-45), made with ASCA on November 10-11, 1993. The energy spectrum was extremely soft and accompanied by a hard tail, characteristics of the Galactic black-hole binaries in the soft state. It is well represented by a two component model consisting of a multicolor disk model or a general relativistic accretion disk model, both describing emission from an optically-thick accretion disk, and a power-law component with a photon index of ∼ 2.5. Spectral analysis of the soft component allows estimation of the mass of the central object. For the optically-estimated distance (> 1 kpc) and inclination (> 37°), the mass is estimated to be > 3.1 M. These results strongly support that the compact object is a black hole.

Original languageEnglish
Pages (from-to)449-452
Number of pages4
JournalAdvances in Space Research
Issue number3-4
Publication statusPublished - 2000
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)


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