{
  "bibcode": "2008GCN..7706....1P",
  "body": "D. A. Perley (UC Berkeley), J. X. Prochaska (UCO/Lick), and J. Hennawi \n(UCB) report:\n\nWe imaged the field of Super-AGILE GRB 080507 (Lapshov et al., GCN 7697) \nwith Keck I (+LRIS) during morning twilight starting at 15:03 UT on \n2008-05-08 (31.3 hours after the trigger).  Four exposures were taken in \ng and R filters simultaneously, although due to twilight only the first \ntwo R-band frames were usable.\n\nWe detect the optical afterglow reported by Kann et al. (GCN 7701) at a \nposition of:\n\nRA  =  15:34:43.39\nDec = +56:26:08.28\n(estimated uncertainty of 0.7\")\n\nin R-band.  Our magnitude, calibrated to seven USNO-B1.0 stars, is R = \n22.20 +/- 0.11 at 1.31 days after the trigger.  This supports the \ngenerally non-fading behavior between 1-2 days after burst in \nobservations from the Swift UVOT (Breeveld et al., GCN 7702) and \nTautenberg (Kann et al.).\n\nFor reference, the observed magnitudes of two nearby USNO stars in the \nsame calibration system are:\n\n15:35:10.99 +56:23:57.02  R = 20.53 +/- 0.02\n15:34:47.68 +56:25:16.44  R = 18.63 +/- 0.01",
  "circularId": 7706,
  "createdOn": 1210386836000,
  "email": "dperley@astro.berkeley.edu",
  "subject": "GRB 080507: Keck photometry",
  "submitter": "Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>",
  "eventId": "GRB 080507"
}