TITLE: GCN GRB OBSERVATION REPORT NUMBER: 612 SUBJECT: GRB 000313 - optical transient in the BATSE error box DATE: 00/03/15 03:40:19 GMT FROM: Alberto Castro-Tirado at LAEFF-INTA Alberto Castro-Tirado, LAEFF-INTA (Madrid) and IAA-CSIC (Granada) Jan Soldan and Rene Hudec, ASU (Ondrejov) Petr Pata and Martin Bernas, CVUT-FEL (Prague) Javier Gorosabel, DSRI (Copenhagen) Jose Maria Castro Ceron, ROA (San Fernando) Tomas Mateo Sanguino, INTA-CEDEA (Huelva) Antonio de Ugarte, UCM (Madrid) Jose Angel Berna, UA (Alicante) on behalf of the BOOTES-1 Team Arne Henden, USRA/USNO (Flagstaff) F. Vrba, B. Canzian, H. Harris, USNO (Flagstaff) Xavier Delfosse, IAC (Tenerife) and Scott Barthelmy, NASA-GSFC (Greenbelt) report: "We have obtained several images centred at the BATSE ORIGINAL error box for the rather faint burst GRB 000313 (BATSE trigger 8035) with the wide-field CCD of BOOTES-1 on Mar 13.8868 UT (4-min after the GRB, 5-min exposure time in the I-band) and with the narrow-field CCD attached to the 0.3-m telescope on Mar 14.0847 UT (4.8-h after the event, 10-min exposure time, no filter). Limiting magnitudes of the images are about 13 and 18 respectively. The first frame reveals a bright new source of about 10th mag when comparing with the following images obtained starting 55-min later. This point-like object, with the same PSF than other field stars, is not detected in the rest of BOOTES-1 images taken during the night. The position of this optical transient is AR(2000) = 13h50m07.9s, Dec(2000) =+31 16 49 (+/- 3"). Unfortunately no more frames were obtained at the same position in the time interval 9-min < T < 55-min due to a mosaizing around the field. Further images were acquired at the 1.0-m Jacobus Kapteyn Telescope on March 14.169-14.200 UT (BVRI bands) and at the 1.3-m and 1.55-m USNO telescopes on March 14.216-14.261 UT (R- and I-bands) but no object is detected within the OT error box down to a limiting magnitude of I = 21. Although we cannot exclude at this moment that this object could be due to a satellite glint or to an airplane flash, multiwavelength observations (specially radio and deep optical) are encouraged in order to see whether this could be the optical afterglow to GRB 000313. The images are posted at http://www.laeff.esa.es/~ajct/GRBs/GRB000313".