TITLE: GCN CIRCULAR NUMBER: 6472 SUBJECT: GRB 070529: MARGE Observations DATE: 07/05/30 02:38:59 GMT FROM: Heather Swan at U.of Michigan/ROTSE H. Swan (U Mich), I. Smith (Rice), C. Akerlof (U Mich), and M. Skinner (Boeing) report on behalf of the MARGE collaboration: The AEOS Burst Camera (ABC) on the AEOS telescope, located at the Maui Space Surveillance System on Haleakala, observed the fading counterpart to GRB070529 (Swift trigger 280706 (GCN 6466)). The images are unfiltered 10s exposures which started less than 30 minutes after the trigger and ended ~ 2 hours later. We detect the OT first identified by S. T. Holland et al (GCN 6466). A preliminary analysis gives a magnitude of approximately 19.41 +/-0.04 at 13:20:35 UT. We calibrated the OT to the USNO-B1.0 R2 band magnitude of the nearby 17.35 mag star located at (J2000) RA = 283.73991, DEC = 20.657206. We find that the ABC data fades as a power law decay with index ~-1.1. Further analysis is in progress.