{
  "bibcode": "2010GCN.10400....1C",
  "body": "B. E. Cobb, J. S. Bloom, S. B. Cenko, D. A. Perley (UC Berkeley) report on \nbehalf of a larger collaboration:\n\nWe have obtained multiple epochs of imaging of the field of GRB 091127\n(Troja et al., GCN 10191) using the Gemini Multi-Object Spectrograph \n(GMOS) on the 8 m Gemini South telescope and the ANDICAM instrument\non the 1.3m telescope at CTIO.  For the first ~10 days post-burst, the \noptical afterglow of the GRB (e.g. Smith et al., GCN 10192, Immler et al., \nGCN 10193, Cobb, GCN 10244) dominates the burst's optical emissions. \nAfter 10 days post-burst, however, we find evidence of an additional \ncomponent of light which rises and then fades, and we consider this to be \ndue to an underlying SN related to this GRB.\n\nThe rise and decay characteristics of this GRB-SN are globally similar to \nthose of the prototypical GRB-SN, SN1998bw.  The SN reaches peak \nbrightness at approximately 30 days post-burst, which is consistent with \nthe rise-time  expected for a GRB-SN at redshift z=0.49 (Cucchiara et \nal., GCN 10202 & Thoene et al., GCN 10233). The observed peak magnitude \nof the SN (and any underlying contribution from a host galaxy) is I~21.7. \nCorrecting for a small amount of Galactic reddening (A_V=0.125) and \nassuming little or no host-galaxy reddening (which is consistent with the \nobservations of the optical afterglow of the GRB), the absolute magnitude \nof this GRB-SN is V~-20.5.\n\nObservations and analysis of this GRB-SN are ongoing.",
  "circularId": 10400,
  "createdOn": 1265859912000,
  "email": "bcobb@astro.berkeley.edu",
  "subject": "GRB 091127: Detection of a Supernova",
  "submitter": "Bethany Cobb at UC Berkeley  <bcobb@astro.berkeley.edu>",
  "eventId": "GRB 091127"
}