TITLE: GCN CIRCULAR NUMBER: 14615 SUBJECT: GRB 130427A: Keck/LRIS Observations DATE: 13/05/09 15:39:04 GMT FROM: Daniel Perley at Caltech D. A. Perley and S. Tang (Caltech) report: On the night of 2013-05-09 UT we observed the location of GRB 130427A with the Low Resolution Imaging Spectrometer (LRIS) on the Keck I 10m telescope, during excellent weather conditions (clear skies and 0.7 arcsecond seeing). In a pair of 90 second g-band images we clearly detect the transient superimposed on a faint, extended source that we identify as the host galaxy. While blended with the light of the transient, the diameter of this extended emission is approximately 3 arcseconds, corresponding to a physical size of ~14 kpc at a redshift of z=0.34. The magnitude of the transient at this time (within a 1" aperture centered on the optical position) is: g = 21.23 +/- 0.04 mag (t = 12.00 days) This is consistent (within uncertainties) with the rate of decay seen in recent P60 observations between 1-8 days post-GRB after subtraction of the host galaxy. We also acquired a deep sequence of spectroscopic observations (2000 sec total integration) with LRIS, covering a wavelength range from approximately 3250 to 10300 Angstroms. We observe no broad features or other evidence of contribution of a supernova to the spectrum at this time, similar to as reported from LBT observations two nights previously (Garnavich et al., GCN 14605.) We thank and S. R. Kulkarni and the PTF collaboration for these observations.