{
  "bibcode": "2009GCN..8999....1D",
  "body": "A. de Ugarte Postigo (ESO), J. Gorosabel, A. Sota,\nA.J. Castro-Tirado (IAA-CSIC), S. McBreen (Univ.\nCollege Dublin) and M.R. Zapatero-Osorio (IAC)\nreport on behalf of a larger collaboration:\n\nWe continued the observations of the afterglow (Chornock\net al. GCNC 8979) of GRB 090313 (Mao et al. GCNC 8980)\nfrom the 1.5m OSN telescope at Sierra Nevada Observatory\n(Granada, Spain) in I-band, the 0.8m IAC80 telescope at\nTeide Observatory (Tenerife, Spain) in R-band and the\n2.5m NOT telescope in nIR bands.\n\nThe observations show how the light curve maintains its\nbrightness until at least 0.8341 days after the burst,\nwhere our last image from OSN shows the afterglow at\nI=17.9+/-0.2. This is still stable as compared to the\nreport of Perley et al. (GCNC 8985) 0.12 days after\nthe burst and our previous report (de Ugarte Postigo\net al. GCNC 8992) 0.56 days after the burst. We note\nthat our new magnitude is somehow brighter than the one\nreported by Perley et al. at a similar epoch (GCNC\n8997). This could be due to a calibration issue. We are\nusing USNO-B1.0 stars as reference.\n\nFrom the IAC80 we observe the burst during the plateau\n0.6482 days after the burst at a magnitude of 19.1+/-0.1.\n\nAt NOT telescope we clearly detect the bright afterglow in\nJ and Ks bands with NOTCAM 0.7989 days after the burst at a\nmagnitude of Ks=15.2+/-0.3. We used 2MASS for the calibration,\nwhich is the main source of uncertainty in this value.\n\nObservations continued the following night, where we see a\nstrong drop in the magnitude of the afterglow, which can be\ndetected at I=20.2 +/- 0.4, 1.5547 days after the burst,\nindicating the presence of a break in the light curve.",
  "circularId": 8999,
  "createdOn": 1237091987000,
  "email": "deugarte@iaa.es",
  "subject": "GRB 090313: Light curve steepening",
  "submitter": "Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>",
  "eventId": "GRB 090313"
}