F. Frontera, E. Montanari, Universita' Ferrara, Italy, L. A. Antonelli,
Osservatorio Astronomico di Roma, Italy, P. Giommi, Agenzia Spaziale
Italiana, Rome, Italy, M. R. Daniele, D. Ricci, SAX-SDC, Rome, Italy, A.
Coletta, M. Smith, A. Tesseri, SAX-SOC, Rome, Italy, C. De Libero,
SAX-OCC, Rome, Italy, L. Piro, IAS, CNR, Rome, Italy, on behalf of a large
"The BeppoSAX Wide Field Camera error box of GRB981226 (IAUC
7074) was observed with the BeppoSAX Narrow Field Instruments (NFI)
starting about 11 hr after the burst in the period Dec. 26.878-29.148 UT.
Preliminary analysis of the MECS2+3 data shows a previously unknown X-ray
source, 1SAXJ2329.6-2356, located at RA = 23h29m36s, Dec = -23o55'58''
(equinox 2000.0), with an error radius of 1'. This position is very
close to the centroid of the WFC error box. During the first 33.3 hours
of observation, the 2-10 keV source flux decreases by a factor 3,
from (4.3 +-1.0)x10E-3 cts/s, corresponding to (3.0 +- 0.7)x10E-13
erg sE-1 cmE-2, down to (1.67+-0.46)x10E-3 cts/s corresponding to (0.98 +-
0.30)x10E-13 erg sE-1 cmE-2. The measurements during the subsequent 18.36
hours show that the flux of 1SAXJ2329.6-2356 does not vary significantly
from the last value.