TITLE:   GCN CIRCULAR
NUMBER:  6339
SUBJECT: GRB 070419A: MARGE Observations
DATE:    07/04/20 19:12:03 GMT
FROM:    Heather Swan at U.of Michigan/ROTSE  <hflewell@umich.edu>

H. Swan (U Mich), I. Smith (Rice), C. Akerlof (U Mich), E. Rykoff (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 GRB070419A (Swift trigger 276205 (GCN 6302)). The images are 
unfiltered 10s exposures which started at 10:57:41 UT (~58 minutes after 
the trigger) and ended at 11:53:52 UT.

After coadding our images in sets of 10, we detect the OT first 
identified by Chornock et al (GCN 6304). A preliminary analysis gives a 
magnitude of approximately 20.5+/-0.2 at a mid time of 10:59:11 UT. 
Using the SDSS data provided by Cool et al. (GCN 6318), we calibrate the
OT to the r band magnitude of the nearby 20.434 mag star located at 
(J2000) RA = 182.73852, DEC = 39.93033. We find that the ABC data fades 
  as a power law decay with  index  ~-1.1, consistent with the 
detections  reported by Nishiura et al. (GCN 6308), Smith et al. (GCN 
6315), Updike  et al. (GCN 6317), Iizuka et al. (6317) (prior the ABC 
observations) and Fu et al. (GCN 6311) (after the ABC observations).