{
  "bibcode": "2013GCN.14286....1F",
  "body": "Johan P. U. Fynbo, Dong Xu, Daniele Malesani, Thomas Kruehler \n(DARK/NBI), Dan A. Perley (Caltech), Valerio D'Elia (ASDC, INAF), report \non behalf of the X-shooter GTO GRB collaboration:\n\nWe observed the field of GRB 130131B (Siegel et al., GCN 14159) using \nthe Keck-I telescope equipped with the LRIS instrument. Observations \nwere carried out on 2013 February 10 (9.62 days after the burst), \nsimultaneously in the g and I bands, for a total exposure time of 750 \nand 720 s, respectively.\n\nA source with g = 25.7 (AB) and I = 24.9 (Vega) is detected inside the \nenhanced XRT error circle (which has a radius of 1.8\"; Goad et al., GCN \n14165), at coordinates:\n\nR.A.(J2000) = 11:35:49.31\nDec.(J2000) = +15:02:18.0\n\nWe consider this object to be the likely host galaxy of GRB 130131B.\n\nA spectrum of this source was taken on 2013 March 9 with the ESO VLT \nequipped with the X-shooter spectrograph, covering the wavelength range \n3000-20000 AA. The exposure time was 8x900 s. In the NIR arm, we detect \nthree emission lines, interpreted as [O III] (4960, 5007) and [O II] \n(3727), all at a common redshift z = 2.539. In the UVB arm, the host \ncontinuum is detected down to ~4400 AA, which corresponds to the onset \nof the Lyman alpha forest at the proposed redshift.\n\nWe acknowledge excellent support from the observing staff at Mauna Kea \nand Paranal, in particular Emanuela Pompei, Claudio Melo, and Thomas \nRivinius.",
  "circularId": 14286,
  "createdOn": 1363011628000,
  "email": "malesani@dark-cosmology.dk",
  "subject": "GRB 130131B: host detection and redshift",
  "submitter": "Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>",
  "eventId": "GRB 130131B"
}