Observations of type I X-ray bursts from CIR X-1.

Abstract

EXOSAT has recently observed three X-ray bursts from the direction of Circinus X-1 which have all the properties of type I bursts. These bursts most likely originate from Cir X-1 and the authors therefore identify Cir X-1 as a neutron star and not a black hole. The properties of the new bursts, such as the ratio of the energy released between bursts to that released during a burst, and the blackbody radius, differ from those of earlier bursts from Cir X-1 in a manner similar to that found in EXO 0748-676.