TITLE: GCN CIRCULAR NUMBER: 13643 SUBJECT: GRB 120804A: Possible temporal break in the X-ray light-curve DATE: 12/08/14 20:56:06 GMT FROM: Wen-fai Fong at CFA R. Margutti, W. Fong, and E. Berger (Harvard) report: "We analyzed the Swift-XRT and Chandra observations of the short GRB 120804A (Lien et al. GCN 13573; Troja et al., GCN 13640). Using the data at t>10^4 sec, when the light curve appears less susceptible to variability, we find moderate evidence for a temporal break with a pre-break index of alpha1= 0.7 +\- 0.1, a post-break index of alpha2= 1.9 +\- 0.5, and a break time of about 2x10^5 sec. The F-test indicates 5% probability of chance improvement with respect to a single power-law fit. Plots are available from: https://www.cfa.harvard.edu/~rmargutt/flux_lightcurvefitBPL.pdf https://www.cfa.harvard.edu/~rmargutt/flux_lightcurvefitSPL.pdf Further X-ray observations are required to clarify the nature/presence of the temporal break."