{
  "bibcode": "2008GCN..7233....1P",
  "body": "D. A. Perley and J. S. Bloom (UC Berkeley) report on behalf of the \nGRAASP collaboration:\n\nPreliminary photometry of our first series of r-band observations of the \ncandidate afterglow of GRB 080129 (Immler et al., GCN 7226; Bloom, 7229) \nyields the following magnitudes, calibrated using three DSS stars*:\n\nt=44 min: R = 22.93 +/- 0.06\nt=50 min: R = 22.86 +/- 0.05\nt=56 min: R = 22.78 +/- 0.04\nt=62 min: R = 22.56 +/- 0.04\nt=68 min: R = 22.87 +/- 0.05\n\nAs these magnitudes are approximately consistent with the value reported \nby Kruehler et al. (GCN 7231/7232) we do not confirm general fading \nbehavior of this source over the interval of our observations. \nHowever, we note that the fourth exposure shows statistically \nsignificant evidence of a short-lived rebrightening.  While an \ninstrumental cause has not been ruled out, given the location in the \nGalactic plane of the source and the very slow fading reported by \nKruehler et al. (0.5 mag from 4 to ~94 minutes, atypical of extragalactic \nGRBs), it is possible that the GRB may be an analog of GRB 070610 / \nSWIFT J195509.6+261406 (Pagani et al., GCN 6489; Kasliwal et al. 2007, \narXiv:0708.0226), which showed extensive short-time scale early-time \nvariability above a nearly-constant baseline.  Further observations \n(including rapid-time-series optical observations), and further analysis \nof the X-ray afterglow, are encouraged to further investigate the nature \nof this source.\n\n---\n\n*Calibration stars are:\n\nra            dec            R2\n07:01:10.5033 -07:50:24.020  17.130\n07:01:07.7333 -07:51:24.620  17.040\n07:01:04.7193 -07:50:46.690  17.310\n\n[GCN OPS NOTE(29jan08): Per author's request, the \"Greiner\" citation was changed\nto \"Kruehler\".]",
  "circularId": 7233,
  "createdOn": 1201607294000,
  "email": "dperley@astro.berkeley.edu",
  "subject": "GRB 080129: Gemini-South photometry",
  "submitter": "Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>",
  "eventId": "GRB 080129"
}