{
  "bibcode": "2013GCN.15327....1P",
  "body": "D. A. Perley (Caltech), S. B. Cenko (GSFC), and M. M. Kasliwal (Carnegie\nObservatories/Princeton) report:\n\nWe imaged PTF13dsw, the possible optical counterpart to Fermi trigger\n403206457 (Kasliwal et al., GCN 15324) with the Palomar 60-inch\ntelescope starting at 05:16:19 UT in i, r, and g filters.  Five\nexposures of 180 seconds each were acquired per filter.\n\nCalibrating to USNO B1.0 stars in the field, photometry of the candidate \ngives an approximate magnitude of R = 21.2 (+/- 0.2) in a stack of 15 \nminutes of r-band imaging at midpoint UT 05:40.  As also noted by \nMalesani et al. (GCN 15325) the continued, significant fading relative \nto the previous night is consistent with that of a GRB afterglow and \nstrengthens the association of this source with the Fermi trigger.",
  "circularId": 15327,
  "createdOn": 1381649204000,
  "email": "dperley@astro.caltech.edu",
  "subject": "Fermi403206457: continued P60 observations and fading behavior",
  "submitter": "Daniel Perley at Caltech  <dperley@astro.caltech.edu>"
}