{
  "bibcode": "2003GCN..2503....1A",
  "body": "L.A. Antonelli, V. Testa (INAF-OAR, Rome), D. Fugazza (INAF-OABr, Merate), \nM. Pedani (INAF-TNG, La Palma), L. Piro (INAF-IASF, Rome), S. Covino \n(INAF-OABr, Merate), N. Masetti, (INAF-IASF, Bologna), D. Malesani\n(Sissa, Trieste) on behalf of the larger Italian GRB Collaboration \nreport:\n\n\"On 28 Dec. we imaged the field of the X-ray rich GRB031220 \n(HETE trigger 2976) with the Telescopio Nazionale Galileo and\nDOLORES instrument operated in imaging mode. The observation \nstarted at 00:54 UT and the field was imaged for a total exposure \ntime of 1 hour in the R-band. Seeing varied during the observation \nfrom 1.1'' to 1.4''. \n\nAt the position consistent with four of the X-ray sources observed \nby Chandra and reported by De Pasquale et al. (GCN 2502) we found \nthe following optical counterparts:\n\nChandra \n  ID#     RA          DEC          Rmag   Err(mag)  \n\n  6       4 39 46.49  7 22 19.30   20.61  0.05    \n 27       4 40 03.71  7 20 55.98   19.42  0.05\n 17       4 39 54.82  7 21 49.05   23.10  0.07\n  7       4 39 46.13  7 22 56.26   23.48  0.11\n\n(for errors on positions we assume a conservative value of 0.6\")\n\nFor the other two sources detected by Chandra (#2 and #1 see GCN 2502) \nwe did not find evidence of optical counterparts. We derived a 3 sigma \nlimiting magnitude of R>24 for both sources.\n\nSource #37 (CXOU J043857.1+072449) is out of the field of view. \n\nA further NIR observation of this field is planned at TNG. \n\nWe thank the personnel of TNG for their enthusiastic effort \nto the GRB program.\n\nThis message may be cited\"\n\n\n\n-------------------------------------------------\nThis mail sent through IMP: http://horde.org/imp/",
  "circularId": 2503,
  "createdOn": 1072727703000,
  "email": "angelo@coma.mporzio.astro.it",
  "subject": "GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources",
  "submitter": "Angelo Antonelli at Obs. Astro. di Roma  <angelo@coma.mporzio.astro.it>",
  "eventId": "GRB 031220"
}