TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2503 SUBJECT: GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources DATE: 03/12/29 19:55:03 GMT FROM: Angelo Antonelli at Obs. Astro. di Roma L.A. Antonelli, V. Testa (INAF-OAR, Rome), D. Fugazza (INAF-OABr, Merate), M. Pedani (INAF-TNG, La Palma), L. Piro (INAF-IASF, Rome), S. Covino (INAF-OABr, Merate), N. Masetti, (INAF-IASF, Bologna), D. Malesani (Sissa, Trieste) on behalf of the larger Italian GRB Collaboration report: "On 28 Dec. we imaged the field of the X-ray rich GRB031220 (HETE trigger 2976) with the Telescopio Nazionale Galileo and DOLORES instrument operated in imaging mode. The observation started at 00:54 UT and the field was imaged for a total exposure time of 1 hour in the R-band. Seeing varied during the observation from 1.1'' to 1.4''. At the position consistent with four of the X-ray sources observed by Chandra and reported by De Pasquale et al. (GCN 2502) we found the following optical counterparts: Chandra ID# RA DEC Rmag Err(mag) 6 4 39 46.49 7 22 19.30 20.61 0.05 27 4 40 03.71 7 20 55.98 19.42 0.05 17 4 39 54.82 7 21 49.05 23.10 0.07 7 4 39 46.13 7 22 56.26 23.48 0.11 (for errors on positions we assume a conservative value of 0.6") For the other two sources detected by Chandra (#2 and #1 see GCN 2502) we did not find evidence of optical counterparts. We derived a 3 sigma limiting magnitude of R>24 for both sources. Source #37 (CXOU J043857.1+072449) is out of the field of view. A further NIR observation of this field is planned at TNG. We thank the personnel of TNG for their enthusiastic effort to the GRB program. This message may be cited" ------------------------------------------------- This mail sent through IMP: http://horde.org/imp/