TITLE: GCN GRB OBSERVATION REPORT NUMBER: 885 SUBJECT: GRB 001109 X-ray afterglow with BeppoSAX DATE: 00/11/16 16:02:28 GMT FROM: Filippo Frontera at ITESRE CNR L. Amati, F. Frontera, and E. Pian, Istituto Tecnologie e Studio Radiazioni Extraterrestri, CNR, Bologna; P. Giommi and M. Capalbi, BeppoSAX Science Data Center, Rome; E. Costa and G. Gandolfi, Istituto di Astrofisica Spaziale, CNR, Rome; J. J. M. in 't Zand, Space Research Organization Netherlands; C. Guidorzi, Universita di Ferrara; S. Granata and A. Paolino, BeppoSAX Science Operation Center, Rome, report: "The 2'.5 error box of GRB 001109 provided by the BeppoSAX Wide Field Cameras was observed with the BeppoSAX Narrow Field Instruments from Nov. 10.0762 (16.5 hr after the gamma-ray burst) to 10.9847 UT. A previously unknown source lying inside the error box has been detected by the Medium Energy Concentrator Spectrometer. The source, designated 1SAX J1830.1+5517, is located at R.A. = 18h30m07s.8, Decl. = +55o17'56" (equinox 2000.0; error radius 50") and has an average count rate of 0.00914 +/- 0.0007 count/s in the two MECS units, corresponding to a 2-10-keV flux of (7.1 +/- 0.5) x 10**-13 erg cm**-2 s**-1. The flux decreases by a factor of about 2 during the first 20 000 s of the observation. Due to its fading behavior, 1SAX J1830.1+5517 is likely the x-ray afterglow of GRB 001109. We remark that the position of this source is consistent with that of the previously unknown radio source detected in the GRB 001109 error box by Taylor et al. (GCN 880). A second BeppoSAX NFI observation of the field is in progress." This message can be cited