Discovery of an Extraordinary Luminous And Soft X-ray Transient MAXI J0158-744
Abstract
Monitor of All-sky X-ray Image (MAXI) is an X-ray all-sky monitor in operation now. MAXI GSC and SSC are sensitive in the 2-30 and 0.5-12 keV bands, respectively. On November 11, 2011 (UT), MAXI GSC discovered an unusually luminous and soft X-ray transient, MAXI J0158-744, on the outskirts of the Small Magellanic Cloud (SMC). The outburst lasted for no more than three hours and the luminosity peaked at ∼1040 erg s-1. By the Swift follow-up observation and the optical spectroscopy, we find that the transient was a kind of the nova explosion on a white dwarf in a binary paired with a Be star. We discuss that the outburst can be explained as shock-induced emission caused by a nova explosion in a dense circumstellar medium around a Be star or a photospheric emission on an ignition of a nova explosion. Its fast optical decay (t2 = 1.9 ± 0.2 days) and extremely early turn-on (<0.44 days) of the super-soft X-ray phase suggest that the white dwarf is very massive.
- Publication:
-
Proceedings of the International Symposium "Nanoscience and Quantum Physics 2012" (nanoPHYS'12
- Pub Date:
- 2015
- DOI:
- 10.7566/JPSCP.4.015002
- Bibcode:
- 2015nqp..confa5002M