{
  "bibcode": "2014GCN.17002....1X",
  "body": "D. Xu (DARK/NBI), A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), S. D. \nVergani (CNRS/GEPI), A. J. Levan (Univ. Warwick), J. P. U. Fynbo \n(DARK/NBI), N. R. Tanvir (Univ. Leicester), B. Milvang-Jensen \n(DARK/NBI), D. Malesani (DARK/NBI), K. Wiersema (Univ. Leicester), \nreport on behalf of a larger collaboration:\n\n\nWe observed the field of GRB 141031A (Gompertz et al., GCN 16995) using \nthe VLT X-shooter spectrograph, using the robotic rapid response mode (RRM).\n\nIn a 15-s acquisition image, taken at 7:41:19 UT (22.8 min after the \nGRB1), we identify three objects consistent with, or in the close \nvicinity of, the currently available XRT error circle (1.4\" error \nradius; Evans et al., GCN 16997 and http://www.swift.ac.uk/xrt_positions/).\n\nTheir coordinates are (all J2000):\n\nA)\nRA = 08:34:26.11\nDec = -59:10:04.2\n\nB)\nRA = 08:34:25.73\nDec = -59:10:04.8\n\nC)\nRA = 08:34:26.05\nDec = -59:10:04.9\n\nSources A and C are partially blended. Source B is the one detected by \nGROND (GCN 16996), looks extended in our data (under 0.6\" seeing), and \nis now formally outside the latest XRT position (2.7\"+-1.4\" away). The \nlimiting magnitude of the image is R ~ 21.7. A finding chart is \navailable at http://www.astro.ku.dk/~malesani/GRB/141031A/finder_XS.jpg\n\nA later image (30 s exposure) was taken 104.5 min after the GRB. Image \nsubtraction reveals no obvious variation of any of the sources, despite \nthe significant time difference between the two epochs (factor of 4.5 in \ntime since GRB).\n\nA spectrum was secured of source A, covering the wavelength range \n3000-25,000 AA. Several features are observed in absorption, including \nthe Balmer series from Halpha to H15, and Ca H and K, at z = 0.0013. \nSuch redshift is consistent with the Milky Way or the Local Group, \nthough the corresponding velocity (390 km/s) is substantial for an \norigin in the MW disk.\n\nOur slit did not cover, unfortunately, objects B and C. Further analysis \nis in progress, and we invite further monitoring of these object to \nsingle out variability.\n\nWe acknowldge excellent support from the observing staff in Paranal, in \nparticular Juan Carlos Munoz-Mateos, Francisco Caceres, Rodrigo Romero, \nand Steffen Mieske.",
  "circularId": 17002,
  "createdOn": 1414781204000,
  "email": "malesani@dark-cosmology.dk",
  "subject": "GRB 141031A: VLT/X-shooter optical observations",
  "submitter": "Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>",
  "eventId": "GRB 141031A"
}