Date: 28 Jun 2011
Satellite: XMM-Newton
Depicts: Light curve of Supergiant Fast X-ray Transient IGR J18410-0535
Copyright: E. Bozzo et al., A&A, 531, A130, 2011, reproduced with permission © ESO

This graph shows the light-curve of IGR J18410-0535, a Supergiant Fast X-ray Transient (SFXT), as recorded by XMM-Newton.

SFXTs are binary systems consisting of a neutron star and a blue supergiant star and characterised by abrupt, intense outbursts of X-rays. Typically much fainter than other X-ray binaries, these sources occasionally undergo powerful flares that boost their luminosity, for a few hours, up to the levels of the brightest X-ray binaries known.

The observation shown here started on 15 March 2010 and lasted for about 45 000 seconds, equivalent to 12.5 hours.

Originally planned to study the source in its typical, quiescent state, the observation recorded, with a stroke of luck, an intense flare that lasted for about 4 hours. The huge increase in luminosity is visible in the left part of the graph. The right part of the graph, by contrast, shows the emission of the source after it returned to its normal, dormant state.

The data were collected with the EPIC-PN camera on board XMM-Newton and cover the energy range 0.3-12 keV.