{
  "bibcode": "2009GCN..9563....1M",
  "body": "A. N. Morgan,  C. R. Klein,  J. S. Bloom,  (UC Berkeley), report:\n\nWe observed the location of the optical afterglow of GRB 090618\n(Schady et al., GCN 9512) with the 1.3m PAIRITEL located at Mt.\nHopkins, Arizona. Observations began at 2009-06-18 08:29:40 UT, 71\nseconds after the Swift Trigger, under non-ideal sky conditions. In\nthe initial images, we detect a variable infrared source (identified\nas the IR afterglow) in individual frames of 7.8 second simultaneous\nexposures in the J, H, and Ks bands.\n\nThe preliminary photometry on selected stacks of images yield the\nfollowing photometry:\n\ntime\npost burst exp.   filt  mag   m_err\n[s]        [s]\n\n210        93.6   J     12.7  0.1\n210        93.6   H     12.1  0.1\n210        93.6   Ks    11.4  0.2\n\n2818       327    J     15.1  0.1\n2818       327    H     14.6  0.1\n2818       327    Ks    13.7  0.1\n\n10636      585    J     16.2  0.2\n10636      585    H     15.7  0.2\n10636      585    Ks    >14.8 3-sigma\n\nIntermittent clouds led to highly variable transmission and sky\nbrightnesses during the PAIRITEL observations. All magnitudes are\ngiven in the Vega system, calibrated to 2MASS. No correction for\nGalactic extinction has been made to the above reported values.\nFurther analysis is ongoing.",
  "circularId": 9563,
  "createdOn": 1245718835000,
  "email": "qmorgan@gmail.com",
  "subject": "PAIRITEL observations of GRB 090618",
  "submitter": "Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>",
  "eventId": "GRB 090618"
}