Journal article
A long-term X-ray monitoring of the ultraluminous X-ray source NGC 5408 X-1 with Swift reveals the presence of dips but no orbital period
Monthly notices of the Royal Astronomical Society, Vol.433(2), pp.1023-1038
05/08/2013
DOI: 10.1093/mnras/stt783
Abstract
NGC 5408 X-1 is a well-studied ultraluminous X-ray source (ULX) that has been
seen to emit in X-rays persistently above the Eddington limit of a stellar-mass
black hole for years. In this paper we report on the most extensive X-ray
monitoring of a ULX, using more than four years of observations from the Swift
satellite. We find that the 115 day periodicity reported by Strohmayer (2009)
disappeared after only a few cycles, confirming the suspicion of Foster et al.
(2010) that the periodicity is most likely super-orbital and not the orbital
period of the system. We also report on a clear dipping behaviour of the source
that may be related to a (super)-orbital phenomenon. All these features are
reminiscent of Galactic X-ray binaries and strengthen their link with ULXs.
Deeper observations of a dip could help resolve the ambiguity about the
interpretation of the spectral components of ULXs.
Details
- Title: Subtitle
- A long-term X-ray monitoring of the ultraluminous X-ray source NGC 5408 X-1 with Swift reveals the presence of dips but no orbital period
- Creators
- Fabien Grisé - University of IowaPhilip Kaaret - University of IowaStéphane Corbel - Université Paris DiderotDávid Cseh - Université Paris DiderotHua Feng - Tsinghua University
- Resource Type
- Journal article
- Publication Details
- Monthly notices of the Royal Astronomical Society, Vol.433(2), pp.1023-1038
- DOI
- 10.1093/mnras/stt783
- ISSN
- 0035-8711
- eISSN
- 1365-2966
- Publisher
- Oxford University Press
- Language
- English
- Date published
- 05/08/2013
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199663002771
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