BeppoSAX MAIL n. 99/8: GRB990510: possible X-ray afterglow A BeppoSAX follow-up of GRB990510 started about 8 hr after the burst. Preliminary analysis of the first two orbits of the MECS data at SOC shows a previously unknown strong source in the center of the WFC error circle. Preliminary coordinates are: R.A.(2000)= 204.605 DEC(2000)= -80.490 The error radius is 1.5' Considering its strength, this X-ray source is likely the X-ray afterglow of GB990510. BeppoSAX is continuing its observation. Luigi Piro BeppoSAX Mission Scientist #----------------------------------#------------------------------------------# Luigi Piro | E-mail: Istituto Astrofisica Spaziale | piro@alpha1.ias.rm.cnr.it C.N.R. | SAX program: saxsci@alpha1.ias.rm.cnr.it Via Fosso del Cavaliere | phone: -39-06-4993-4007 I-00133 Roma | phone BeppoSAX center: -39-06-4079-6393 Italy | fax(CNR) : -39-06-20660188 #__________________________________#___________________________________________#