TITLE: GCN GRB OBSERVATION REPORT NUMBER: 145 SUBJECT: GRB 980703 (NFI observations) DATE: 98/07/17 16:59:48 GMT FROM: Paul Vreeswijk at U of Amsterdam T.J. Galama, P.M. Vreeswijk (U. of Amsterdam), J. van Paradijs (U. of Amsterdam and U. of Alabama in Huntsville), C. Kouveliotou (USRA/MSFC), L.A. Antonelli (Astronomical Observatory of Rome and SAX-SDC, Rome), V. Torroni (SAX-SOC Rome), and C. Pastor (Dataspazio, Rome), on behalf of a larger collaboration, report: "We have analyzed a second BeppoSAX NFI observation of the RXTE/ASM error box (Smith et al. GCN #126) of GRB 980703 made July 7.779-8.706 UT. Preliminary analysis of the combined MECS 2 and 3 data shows that the variable X-ray source 1SAX J2359.1+0835 (Galama et al. GCN #127), positionally coincident with the radio counterpart (Frail et al. GCN #128) decayed by a factor 5.5 +- 1.5 between July 4 and 8. Assuming a power law light curve we find a decay index of 1.33 +- 0.25" This message is citeable.