TITLE: GCN GRB OBSERVATION REPORT NUMBER: 61 SUBJECT: report on BSAX observations of GRB980425 DATE: 98/04/29 20:23:22 GMT FROM: Elena Pian at ITESRE-CNR,Bologna GRB980425 E. Pian, Istituto TESRE, CNR, Bologna, Italy, L. A. Antonelli, M. R. Daniele, S. Rebecchi, SAX-SDC, Rome, Italy, V. Torroni, SAX-SOC, Rome, Italy, G. Gennaro, SAX-OCC, Rome, Italy, M. Feroci, L. Piro, IAS, CNR, Rome, Italy, report: "The BeppoSAX Wide Field Camera error box of GRB980425 (IAUC 6884) was observed with the BeppoSAX Narrow Field Instruments (NFI) starting about 10.0 hr after the burst in the period April 26.31-28.16 UT. Preliminary analysis of the data shows two previously unknown X-ray sources in the LECS and MECS: 1SAXJ1935.0-5248 and 1SAXJ1935.3-5252, located at RA = 19h35m04s, Dec = -52o48'33'' and at RA = 19h35m21s, Dec = -52o52'19'' (equinox 2000.0), respectively, with an error radius of 1' each. These positions are 2' and 4'.7 away from the centroid of the WFC error box, respectively. During the first 27.7 hours of observation, the average count rates in the two MECS units (1.6-10 keV) were (4.5 +- 0.7)x10E-3 cts/s, corresponding to (3.0 +- 0.4)x10E-13 erg sE-1 cmE-2 in the 2-10 keV range, for 1SAXJ1935.0-5248 and (2.4 +- 0.5)x10E-3 cts/s for 1SAXJ1935.3-5252, equivalent to (1.6 +- 0.3)x10E-13 erg sE-1 cmE-2 (2-10 keV). The measurements during the subsequent 16.6 hours showed that 1SAXJ1935.0-5248 did not vary significantly from the first epoch. 1SAXJ1935.3-5252 was not detected at the second epoch, with a 3 sigma upper limit of 1.8x10E-3 cts/s. This indicates a decay by a factor of 1.3 or more in 22 hours. A further BeppoSAX observation is already planned to monitor the behavior of both sources."