{
  "bibcode": "2013GCN.14302....1D",
  "body": "A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), \nJ. Gorosabel (IAA-CSIC), R. Sanchez-Ramirez (IAA-CSIC), J. P. U. Fynbo \n(DARK/NBI) and N. Tanvir (U. Leicester) report:\n\nWe have observed the field of the short GRB 130313A (Gompertz et al., \nGCN 14293) using the 10.4m GTC. Observations started at 5:22 UT \n(13.23 hr after the burst) and were performed in the r-band in good conditions \nand a seeing of ~0.8\". The combined 8x120s exposure covers the complete \nrefined BAT error box (Barthelmy et al., GCN 14296).\n\nWe detect a point-like source at the edge of the suggested X-ray afterglow \n(Osborne et al., GCN 14300) for which we estimate a preliminary magnitude \nof r=26.3+/-0.4, as compared with SDSS stars (we note that the photometry is\ncomplicated by a nearby bright star). This object is located at the following \ncoordinates (J2000, +/-0.5\"):\n\nS1:\nR.A.: 15:45:38.45\nDec.: -00:22:03.5\n\nThere are two other marginally detected sources consistent with the XRT error \nbox, one unresolved at:\n\nS2:\nR.A.: 15:45:38.21\nDec.: -00:22:10.3\n\nAnd one extended:\n\nS3:\nR.A.: 15:45:38.64\nDec.: -00:22:04.7\n\nA finding chart with these sources can be found at:\nhttp://www.iaa.es/~deugarte/GRBs/130313A/130313A_GTC.jpg\n\nFurther observations in search for variability will be needed to determine the relation \nof any of these sources with GRB 130313A.",
  "circularId": 14302,
  "createdOn": 1363244145000,
  "email": "deugarte@iaa.es",
  "subject": "GRB130313A: Optical observations from GTC",
  "submitter": "Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>",
  "eventId": "GRB 130313A"
}