Discovery of X-ray bursts from Aquila X-1

Two X-ray bursts were observed from the recurrent transient Aql X-1 during the declining phase of a nova-like flare. These bursts exhibit common characteristics of typical X-ray bursts. The observed ratio of the persistent flux to the burst peak flux was about 0.02, which is about the same as the value for the burst observed from Cen X-4 during its outburst. Combined with the optical data during the X-ray quiescent state, the discovery of X-ray bursts from Aql X-1 gives strong support for the picture of X-ray bursters as binaries composed of a late dwarf and a neutron star.