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GCN Circular 2021

GRB 030329: Optical Decay
2003-03-30T11:16:08Z (21 years ago)
Jules Halpern at Columbia U. <>
J. P. Halpern, N. Mirabal, M. Bureau (Columbia U.), K. Fathi (U. Nottingham)
report for the MDM Observatory follow-up team:

We monitored the optical afterglow of GRB 030329 (=H2652, Vanderspek et al.
GCN 1997), identified by Peterson & Price (GCN 1985) and Torii (GCN 1986),
in the R-band with the MDM 1.3m for 7.5 hours beginning on March 30 03:05 UT, 
15.5 hours after the burst.  During this period, the magnitude declined from
R = 15.38 to R = 16.22, referenced to star "A" of Martini et al. (GCN 2012).
A fit to the 7.5 hour run yields a power-law decay slope of -1.934 +/- 0.005,
in agreement with contemporaneous measurements of Garnavich et al. (GCN 2018) 
and Smith (GCN 2019), although it is apparent that the slope is continuing to 
steepen further.

A graph of the preliminary differential magnitude light curve is available at

We thank J. Kemp for providing the data reduction pipeline.

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