Discovery of X-ray Bursts from Two Sources in Aquila*

Abstract

Two X-ray burst sources have been discovered in Aquila. The sources are designated MXB 1906 + 00 and Aql MXB. The interval between bursts from MXB 1906 + 00 (five bursts were observed) was ~ 8·9 hr (5·6 per cent rms jitter); the average total flux in the bursts was |$\sim 1\cdot 3\times{10}^{-7}\,\text{erg}/\text{cm}^{2}$|⁠. The spectra of the bursts from MXB 1906 + 00, softens during decay, whereas the spectrum of the one burst observed from Aql MXB did not change significantly. The previously known source A 1905 + 00 is located near the error box of MXB 1906 + 00, and it is likely that the two are the same source. If so, then the ratio of time-averaged ‘ steady ’ luminosity to the time-averaged burst luminosity is ~ 80. The discovery of these two sources raises the number of known burst sources to 15.