{
  "bibcode": "2013GCN.14615....1P",
  "body": "D. A. Perley and S. Tang (Caltech) report:\n\nOn the night of 2013-05-09 UT we observed the location of GRB 130427A \nwith the Low Resolution Imaging Spectrometer (LRIS) on the Keck I 10m \ntelescope, during excellent weather conditions (clear skies and 0.7 \narcsecond seeing).\n\nIn a pair of 90 second g-band images we clearly detect the transient \nsuperimposed on a faint, extended source that we identify as the host \ngalaxy.  While blended with the light of the transient, the diameter of \nthis extended emission is approximately 3 arcseconds, corresponding to a \nphysical size of ~14 kpc at a redshift of z=0.34.  The magnitude of the \ntransient at this time (within a 1\" aperture centered on the optical \nposition) is:\n\n  g = 21.23 +/- 0.04 mag  (t = 12.00 days)\n\nThis is consistent (within uncertainties) with the rate of decay seen in \nrecent P60 observations between 1-8 days post-GRB after subtraction of \nthe host galaxy.\n\nWe also acquired a deep sequence of spectroscopic observations (2000 sec \ntotal integration) with LRIS, covering a wavelength range from \napproximately 3250 to 10300 Angstroms.   We observe no broad features or \nother evidence of contribution of a supernova to the spectrum at this \ntime, similar to as reported from LBT observations two nights previously \n(Garnavich et al., GCN 14605.)\n\nWe thank and S. R. Kulkarni and the PTF collaboration for these \nobservations.",
  "circularId": 14615,
  "createdOn": 1368113944000,
  "email": "dperley@astro.caltech.edu",
  "subject": "GRB 130427A: Keck/LRIS Observations",
  "submitter": "Daniel Perley at Caltech  <dperley@astro.caltech.edu>",
  "eventId": "GRB 130427A"
}