{
  "subject": "GRB 090323: TLS detection at 5 days, no break",
  "eventId": "GRB 090323",
  "bibcode": "2009GCN..9041....1K",
  "createdOn": 1238214205000,
  "circularId": 9041,
  "submitter": "Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>",
  "email": "kann@tls-tautenburg.de",
  "body": "D. A. Kann, U. Laux and B. Stecklum (TLS Tautenburg) report:\n\nWe observed the afterglow (Updike et al., GCN 9026, Cenko et al. GCN 9027) \nof the intense Fermi GBM/LAT GRB 090323 (Ohno et al., GCN 9021) with the \n1.34m Schmidt telescope of the TLS Tautenburg observatory under decent \nconditions (low transparency). We obtained 11 Rc frames of 600 seconds \nexposure time each before dawn shut us down. The afterglow is faintly \ndetected in some single images and well-detected in the \ncomplete stack.\n\nUsing the same comparison star as Kann et al. (GCN 9033), we measure the \nfollowing afterglow magnitude:\n\ndays after trigger\tRc\tdRc (statistical)\n\n5.10418\t\t\t22.67\t0.20\n\nUsing other published data (Updike et al., GCN 9026, Wang et al., GCN \n9034, Perley et al. GCN 9036, Guidorzi et al., GCN 9039) as well as \nadditional TLS data from the first observation run, we find that all data \nagree decently well with a single power law decay with a slope alpha ~ \n1.8. Therefore, there does not seem to be a plateau phase, but there is \nalso no sign of a break yet. The relatively steep decay makes it unclear \nif this is a steep pre-break decay slope or a shallow post-break decay \nslope. In the latter case, it will be possible to track the afterglow for \na very long time. Further deep, high S/N observations with larger \ntelescopes are advised.\n\nThis message may be cited."
}