Journal article
A 62 day X-ray periodicity and an X-ray flare from the ultraluminous X-ray source in M82
The Astrophysical journal, Vol.646(1), pp.174-183
07/20/2006
DOI: 10.1086/504830
Abstract
In 240 days of X-ray monitoring of M82, we have discovered an X-ray periodicity at 62.0 ± 2.5 days with a peak-to-peak amplitude corresponding to an isotropic luminosity of 2.4 × 1040 ergs s-1 in M82 and an X-ray flare reaching a peak luminosity of 9.8 × 1040 ergs s-1. The periodicity and flare likely originate from the ultraluminous X-ray source (ULX) in M82, which has been identified as a possible intermediate-mass black hole. We suggest that the 62 day modulation is due to orbital motion within an X-ray binary with a Roche lobe overflowing companion star, which would imply that the average density of the companion star is near 5 × 10-5 g cm-3 and is therefore a giant or supergiant. Chandra observations just after the flare show an energy spectrum that is consistent with a power law with no evidence of a thermal component or line emission. Radio observations made with the VLA during the flare allow us to rule out a blazar identification for the source and place strong constraints on relativistically beamed models of the X-ray emission. The Chandra observations reveal that a second X-ray source reached a flux of 4.4 × 10-12 ergs cm-2 s-1 in the 0.3-7 keV band, which is dramatically higher than any flux previously seen from this source and corresponds to an isotropic luminosity of 1.1 × 1040 ergs s-1. This source is a second ultraluminous X-ray source in M82 and may give rise to the QPOs detected from the central region of M82. © 2006. The American Astronomical Society. All rights reserved.
Details
- Title: Subtitle
- A 62 day X-ray periodicity and an X-ray flare from the ultraluminous X-ray source in M82
- Creators
- Philip Kaaret - University of IowaMelanie G Simet - University of IowaCornelia C Lang - University of Iowa
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.646(1), pp.174-183
- DOI
- 10.1086/504830
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Publisher
- University of Chicago Press
- Language
- English
- Date published
- 07/20/2006
- Academic Unit
- Liberal Arts and Science Admin; Physics and Astronomy
- Record Identifier
- 9984428772302771
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