Letter to the Editor
A superburst from GX 3+1
SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands
Corresponding author: firstname.lastname@example.org
Accepted: 18 December 2001
I found one long X-ray flare from the X-ray burster GX 3+1 in almost 6 years of observations with the RXTE All Sky Monitor (ASM). The event had a peak flux of about 1.1 Crab (1.5–12 keV), lasted between 4.4 and 16.2 hours and exhibited a fluence of more than about 51041 erg for a source distance of 5 kpc. During the exponential-like decay, with an exponential decay time of 1.6 hours, spectral softening is seen. The total ASM effective exposure time on GX 3+1 is estimated to be around a year. The flare bears all the characteristics of the recently discovered so-called superbursts in other X-ray burst sources.
Key words: accretion, accretion disks / binaries: close / stars: individual (GX 3+1) / stars: neutron / X-rays: bursts
© ESO, 2002