A new Ultraluminous X-ray source in the galaxy NGC 5907
Jun 10, 20185 pages
Published in:
- Mon.Not.Roy.Astron.Soc. 477 (2018) 1, L90-L95
- Published: Jun 11, 2018
e-Print:
- 1806.03633 [astro-ph.HE]
DOI:
- 10.1093/mnrasl/sly048 (publication)
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Abstract: (Oxford University Press)
We report on the serendipitous discovery of a new transient in NGC 5907, at a peak luminosity of 6.4 × 10^39 erg s^−1. The source was undetected in previous 2012 Chandra observations with a 3σ upper limit on the luminosity of 1.5 × 10^38 erg s^−1, implying a flux increase of a factor of >35. We analysed three recent 60 ks/50 ks Chandra and 50 ks XMM–Newton observations, as well as all the available Swift/XRT observations performed between 2017 August and 2018 March. Until the first half of 2017 October, Swift/XRT observations did not show any emission from the source. The transient entered the ultraluminous X-ray source (ULX) regime in less than two weeks and its outburst was still on-going at the end of 2018 February. The 0.3–10 keV spectrum is consistent with a single multicolour blackbody disc (kT ∼ 1.5 keV). The source might be an ∼30 M_⊙ black hole accreting at the Eddington limit. However, although we did not find evidence of pulsations, we cannot rule out the possibility that this ULX hosts an accreting NS.Note:
- Accepted on MNRAS, 5 pages, 2 figure, 1 table
- accretion, accretion discs
- X-rays: binaries
- X-rays: galaxies
- X-rays: individual: NGC 5907 ULX-2
References(59)
Figures(4)