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SWIFT OBSERVATIONS OF THE ULTRALUMINOUS X-RAY SOURCE HOLMBERG IX X-1
Journal article   Open access   Peer reviewed

SWIFT OBSERVATIONS OF THE ULTRALUMINOUS X-RAY SOURCE HOLMBERG IX X-1

A. K. H Kong, T.-C Yen, Y. J Yang, H Feng and P Kaaret
The Astrophysical journal, Vol.722(2), pp.1816-1820
10/20/2010
DOI: 10.1088/0004-637X/722/2/1816
url
https://doi.org/10.1088/0004-637X/722/2/1816View
Published (Version of record) Open Access

Abstract

Holmberg IX X-1 is a well-known ultraluminous X-ray source with an X-ray luminosity of {approx}10{sup 40} erg s{sup -1}. The source has been monitored by the X-ray telescope of Swift regularly. Since 2009 April, the source has been in an extended low luminosity state. We utilize the co-added spectra taken at different luminosity states to study the spectral behavior of the source. Simple power-law and multi-color disk blackbody models can be ruled out. The best overall fits, however, are provided by a dual thermal model with a cool blackbody and a warm disk blackbody. This suggests that Holmberg IX X-1 may be a 10 M{sub sun} black hole accreting at seven times above the Eddington limit or a 100 M{sub sun} maximally rotating black hole accreting at the Eddington limit, and we are observing both the inner regions of the accretion disk and outflows from the compact object.
Physical Properties Telescopes ACCRETION DISKS ASTROPHYSICS, COSMOLOGY AND ASTRONOMY BLACK HOLES COLOR COSMIC RAY SOURCES COSMIC X-RAY SOURCES ELECTROMAGNETIC RADIATION IONIZING RADIATIONS LUMINOSITY OPTICAL PROPERTIES ORGANOLEPTIC PROPERTIES RADIATIONS STARS X RADIATION

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