{
  "bibcode": "2013GCN.14552....1M",
  "body": "D. Malesani (DARK/NBI), P. D'Avanzo (INAF/OABr), S. Covino (INAF/OABr), \nA. Melandri (INAF/OABr), V. D'Elia (INAF/OAR and ASI/ASDC), S. Campana \n(INAF/OABr), D. Fugazza (INAF/OABr), G. Tagliaferri (INAF/OABr), B. Blu, \nL. Di Fabrizio (INAF/FGG), C. P. Padilla-Torres (INAF/FGG), report on \nbehalf of the CIBO collaboration:\n\nWe observed the field of the LAT-detected GRB 130502B (Von Kienlin & \nYounes, GCN 14530; Kocevski et al., GCN 14532; Golenetskii et al., GCN \n14542) with the TNG equipped with the DOLoRes imager. Observations were \ncarried out starting on 2013 May 3.872 UT (1.54 days after the trigger), \nfor a total of 30 min on source in the R band, at a high airmass of \naround 2.2. The seeing was 1.2\".\n\nNo bright object is detected inside the X-ray error circle (Melandri & \nImmler, GCN 14540; see also http://www.swift.ac.uk/xrt_positions/), down \nto a 3-sigma limit of R = 23.7 (calibration based on several nearby USNO \nstars). However, a faint flux enhancement is seen consistent with the \nXRT position, at coordinates (J2000):\n\nRA = 04:27:02.82\nDec = +71:03:38.5\n\nA finding chart is shown at \nhttp://www.astro.ku.dk/~malesani/GRB/130502B/GRB130502B_finder.jpg\n\nWe estimate the magnitude of this marginally detected source to be R = \n24.7 +- 0.5. At the moment, we have no information about its \nvariability, and it could be either the GRB counterpart or its host galaxy.\n\nLast, independently of the reality of the object, this GRB can be \nclassified as dark. Considering the limit R > 23.7, and a Galactic \nextinction A_V = 0.57 (Schlafly & Finkbeiner 2011, ApJ, 737, 103), the \noptical-to-X-ray spectral index is beta_OX < 0.47 (if the object is \nreal, then beta_OX = 0.34 +- 0.07). The presence of significant excess \ncolumn density in the X-ray spectrum (Melandri & Immler, GCN 14540; see \nalso http://www.swift.ac.uk/xrt_spectra/00020266/) suggests an \nextinguished event.\n\n[GCN OPS NOTE(04may13): Per author's request, the URL in the last paragraph\nwas change from the team-internal version to the public version.]",
  "circularId": 14552,
  "createdOn": 1367659150000,
  "email": "malesani@dark-cosmology.dk",
  "subject": "GRB 130502B: possible TNG counterpart",
  "submitter": "Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>",
  "eventId": "GRB 130502B"
}