TITLE: GCN GRB OBSERVATION REPORT NUMBER: 596 SUBJECT: GRB 000301c: K' observations DATE: 00/03/07 04:23:14 GMT FROM: James Rhoads at STScI James Rhoads and Andy Fruchter (STScI) report: We observed the candidate counterpart of GRB 000301c for a third time with the NASA-IRTF + NSFCam on March 6.595. The magnitude of the transient relative to the reference star 6" west has decayed to +2.60 +- 0.12, giving K'=18.56 +- 0.12 (statistical error only). This is a decay of 0.56 magnitudes since our preceding observation (on March 5.61 UT), and so the decay of the 2.1 micron flux continues to accelerate. The K' band light curve is a considerably worse fit to any power law than the R band light curve. This unusual behavior warrants closer investigation, and further followup at all wavelengths (especially the near-IR) is encouraged.