Burst-properties as a function of mass accretion rate in GX 3+1

den Hartog, P. R.; in't Zand, J. J. M.; Kuulkers, E.; Cornelisse, R.; Heise, J.; Bazzano, A.; Cocchi, M.; Natalucci, L.; Ubertini, P.
Referencia bibliográfica

Astronomy and Astrophysics, v.400, p.633-641 (2003)

Fecha de publicación:
3
2003
Número de autores
9
Número de autores del IAC
0
Número de citas
24
Número de citas referidas
21
Descripción
GX 3+1 is a low-mass X-ray binary that is persistently bright since its discovery in 1964. It was found to be an X-ray burster twenty years ago proving that the compact object in this system is a neutron star. The burst rate is so low that only 18 bursts were reported prior to 1996. The Wide Field Cameras on BeppoSAX have, through a dedicated monitoring program on the Galactic center region, increased the number of X-ray bursts from GX 3+1 by 61. Since GX 3+1 exhibits a slow (order of years) modulation in the persistent flux of about 50%, these observations opens up the unique possibility to study burst properties as a function of mass accretion rate for very low burst rates. This is the first time that bursts are detected from GX 3+1 in the high state. From the analysis we learn that all bursts are short with e-folding decay times smaller than 10 s. Therefore, all bursts are due to unstable helium burning. Furthermore, the burst rate drops sixfold in a fairly narrow range of 2-20 keV flux; we discuss possible origins for this.