{
  "bibcode": "2009GCN..8997....1P",
  "body": "D. A. Perley (UC Berkeley) reports on behalf of a larger collaboration:\n\nFollowing our spectroscopic integration on the optical afterglow of GRB\n090313 (GCN 8994), we acquired one 60s frame in each of g, r, i, and z\nfilters using Gemini-S (GMOS) in imaging mode between 05:11 and 05:18 UT\n(20.07 hours after the burst).  We report the following magnitudes:\n\ng = 21.62 +/- 0.08\nr = 20.12 +/- 0.03\ni = 19.50 +/- 0.05\nz = 19.03 +/- 0.05\n\nThe optical SED is well-fit assuming a moderate (A_V ~< 0.4) amount of\nSMC-like dust extinction.  The presence of a 2175 A dust feature is\nstrongly ruled out by the z-band measurement.",
  "circularId": 8997,
  "createdOn": 1237027098000,
  "email": "dperley@astro.berkeley.edu",
  "subject": "GRB 090313: Gemini-S photometry",
  "submitter": "Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>",
  "eventId": "GRB 090313"
}