{
  "bibcode": "2009GCN..9420....1R",
  "body": "A. Rossi (Tautenburg), T. Kruehler and J. Greiner (both MPE Garching) \nreport on behalf of the GROND team:\n\nGROND (Greiner et al. 2008, PASP 120, 405) at the 2.2m ESO/MPI telescope at La\n Silla Observatory (Chile) \nstarted follow-up observations of GRB 090520 (Cummings et al. 2009, GCN #9417)\n on May 21, at 09:35 UTC \n(~32 h after the burst). In addition, a second epoch of imaging was obtained,\n which started on May 22, 09:37 UTC.\n\nImage subtraction does not reveal any variable source between the two epochs. \nThe first epoch thus yields the following upper limits:\n\ng > 23.8\nr > 24.0\ni > 23.4\nz > 23.2\nJ > 21.8\nH > 21.4\nK > 20.8\n\nobtained using the GROND zeropoints and 2MASS field stars as reference.",
  "circularId": 9420,
  "createdOn": 1243036415000,
  "email": "rossi@tls-tautenburg.de",
  "subject": "GRB 090520: GROND upper limits",
  "submitter": "Andrea Rossi at TLS Tautenburg  <rossi@tls-tautenburg.de>",
  "eventId": "GRB 090520"
}