TITLE: GCN GRB OBSERVATION REPORT NUMBER: 127 SUBJECT: BeppoSAX NFI observations of GRB 980703 DATE: 98/07/06 22:25:08 GMT FROM: Titus Galama at U.Amsterdam T.J. Galama (U. of Amsterdam), J. van Paradijs (U. of Amsterdam and U. of Alabama in Huntsville), L.A. Antonelli (Astronomical Observatory of Rome and SAX-SDC, Rome), P. Vreeswijk (U. of Amsterdam), C. Kouveliotou (USRA/MSFC), V. Torroni (SAX-SOC Rome), and C. Pastor (Dataspazio, Rome), on behalf of a larger collaboration, report: "We have observed the RXTE/ASM error box of GRB980703 with the BeppoSAX Narrow Field Instruments (NFI) starting about 22 hr after the burst in the period July 4.096-5.084 UT. Preliminary analysis of the data shows a previously unknown X-ray source 1SAX J2359.1+0835 in the LECS and MECS at RA = 23h59m07s, Dec = +08d35'33" (equinox 2000.0), with an error radius of 50" (inside the refined RXTE/ASM error box; GCN/RXTE_ASM note July 6 1998). In the first 8200 sec of the observation the average count rate was (1.14 +- 0.16)x10^-2 cts/s in the combined data of MECS 2 and 3, corresponding to a flux of 7.5 x 10^-13 ergs cm^-2 s^-1. In the last 30000 sec the average count rate was reduced to (7.3 +- 0.7)x10^-3 cts/s corresponding to a flux of 4.8 x 10^-13 ergs cm^-2 s^-1. In addition the field contains the sources 1SAX J2359.9+0834 at RA = 23h59m59s, Dec= +08d34'03" and 1SAX J0000.1+0817 at RA = 00h00m04s Dec=+08d17'14". Both these sources are outside the RXTE/ASM error box, do not show any significant variability and are coincident with ROSAT sources, 1RXS J235959.1+083355 and 1RXS J000007.0+081653, respectively. A new follow-up observation will be performed with the BeppoSAX NFI." This message is citeable.