{
  "bibcode": "2017GCN.21059....1I",
  "body": "������L. Izzo, Z. Cano (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI),\nD. A. Kann, C. Thoene (IAA-CSIC), and S. Geier (IAC, GRANTECAN) report on\nbehalf of a larger collaboration:\n\nWe observed the field of short-duration GRB 170428A (Beardmore et al., GCN\nCirc. 21042) with OSIRIS mounted on the 10.4-m GTC telescope on La Palma\n(Spain) starting at 04:31:49 UT on 01 May 2017, at a mean time of +2.82\ndays from the GRB detection. The observations consisted of 4 x 900 s\nspectra using grism R1000R, which covers the wavelength range between 5100\nand 10000 AA.\n\nIn our r-band acquisition image, (30 second exposure time), we see the host\ncandidate of Xu et al. (GCN Circ. 21048), which is also slightly visible in\nthe r-band Pan-STARRS image.  The slit was centred on the host galaxy\ncandidate, and in the faint trace we detect emission lines corresponding to\nHalpha, [OIII] 5007, Hbeta, and [OII] 3726,3729, all at a common redshift\nof z=0.454.  The angular separation between the candidate host and the GRB\nposition determed by GROND (Bolmer et al., GCN Circ. 21050) is 1.2'' +-\n0.3'', which at this redshift implies an offset of 6.9 kpc +- 1.7 kpc.\n\nGTC finder chart of the AG position and candidate host:\nhttp://www.iaa.es/~deugarte/GRBs/170428A/GTC.jpeg",
  "circularId": 21059,
  "createdOn": 1493747027000,
  "email": "zewcano@gmail.com",
  "subject": "GRB 170428A: GTC spectroscopic redshift of candidate host galaxy",
  "submitter": "Zach Cano at U of Iceland  <zewcano@gmail.com>",
  "eventId": "GRB 170428A"
}