{
  "bibcode": "2012GCN.13926....1S",
  "body": "V. Sudilovsky (MPE Garching), D. A. Kann (MPE Garching/Universe Cluster),\nT. Kr�hler (DARK, Copenhagen), and J. Greiner (MPE Garching) report on\nbehalf of the GROND team:\n\nFollowing two days of bad weather delay, we observed the field of GRB\n121027A (Evans et al., GCN 13906) simultaneously in g'r'i'z'JHK with GROND\n(Greiner et al. 2008, PASP, 120, 405) mounted on the 2.2 m MPG/ESO\ntelescope at La Silla Observatory (Chile).\n\nObservations began at 08:10 on October 29th (mid-time ~2.05 days\npost-trigger). They were performed at an average seeing of 1.6\" (r'-band)\nand at an average airmass of 1.2.\n\nWe detect the NIR afterglow reported by Starling et al. (GCN 13911) and\nLevan et al. (GCN 13920) in all seven bands.\n\nBased on a 460 sec integration in g'r'i'z' and 1200 sec integration in\nJHK, we measure preliminary magnitudes (all in AB system) of\n\ng' = 22.1 +/- 0.2 mag\nr' = 21.6 +/- 0.1 mag\ni' = 21.3 +/- 0.1 mag\nz' = 20.9 +/- 0.1 mag\nJ  = 20.4 +/- 0.1 mag\nH  = 19.7 +/- 0.1 mag\nK  = 19.0 +/- 0.1 mag\n\nWe note an increase of brightness by ~ 1 magnitude relative to the\nobservations reported by Levan et al. (GCN 13920) at 32 hours after the\nGRB.\n\nOur detection in all bands constrains the redshift of this burst to z < 3.5.\n\nGiven magnitudes are calibrated against GROND zeropoints in the optical,\nand 2MASS field stars in the NIR, and are not corrected for the expected\nGalactic foreground extinction corresponding to a reddening of E(B-V) =\n0.02 mag in the direction of the burst (Schlegel et al. 1998).",
  "circularId": 13926,
  "createdOn": 1351540089000,
  "email": "kann@tls-tautenburg.de",
  "subject": "GRB 121027A: GROND Confirmation of Rebrightening",
  "submitter": "Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>",
  "eventId": "GRB 121027A"
}