1SAX J0835.9+5118
Abstract
G. Gandolfi, A. Coletta, and D. Ricci, BeppoSAX Scientific Operation Center, Telespazio, Rome; J. Heise and J. in't Zand, Space Research Organization of the Netherlands, Utrecht; and L. Piro, E. Costa, and M. Feroci, Istituto di Astrofisica Spaziale, CNR, Rome, write: "On May 20.08539 UT a fast x-ray transient, which we designate 1SAX J0835.9+5118, has been detected in BeppoSAX Wide Field Camera unit 1 (2-28 keV). The event lasted about 10 s, with a peak flux of 1 Crab in the range 2-25 keV. The burst shows two peaks; in coincidence with the second, harder burst, the GRB Monitor (40-700 keV) obtained a marginal detection (4-sigma signal) corresponding to a flux of about 1.8 Crab. The position is R.A. = 8h35m56s, Decl. = +51o18'.6 (equinox 2000.0), with an error radius of 3'. No catalogued source at any wavelength lies in the error box. Furthermore, no quiescent emission was found from this source during 3 hr following the outburst, with an upper limit of 6 mCrab (2-10 keV), and in a combination of 1996-1999 data, with an upper limit of 0.6 mCrab. The normalized flux differences F_1-F_2 and F_2-F_3 (where F_1, F_2, and F_3 are the fluxes in the bands 20-26, 7-20, and 3-7 keV) are -0.62 and +0.05, respectively. These values are typically softer than GRBs and fall in the same range as type-I x-ray bursters. Follow-up observations are encouraged to investigate the nature of this object."
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- May 1999
- Bibcode:
- 1999IAUC.7174....1G