We obtained 98 R-band and 18 B, r', i' images of the optical afterglow of GRB
060526 (z=3.21) with the MDM 1.3m, 2.4m, and the PROMPT telescopes in Cerro
Tololo over the 5 nights following the burst trigger. Combining these data with
other optical observations reported in GCN and the Swift-XRT observations, we
compare the optical and X-ray afterglow light curves of GRB 060526. Both the
optical and X-ray afterglow light curves show rich features, such as flares and
breaks. The densely sampled optical observations provide very good coverage at
T>1.e4 sec. We observed a break at 2.4e5 sec in the optical afterglow light
curve. Compared with the X-ray afterglow light curve, the break is consistent
with an achromatic break supporting the beaming models of GRBs. However, the
pre-break and post-break temporal decay slopes are difficult to explain in
simple afterglow models. We estimated a jet angle of \theta_j ~ 7 degrees and a
prompt emission size of R_{prompt} ~ 2e14 cm. In addition, we detected several
optical flares with amplitudes of \Delta m ~ 0.2, 0.6, and 0.2 mag. The X-ray
afterglows detected by Swift have shown complicated decay patterns. Recently,
many well-sampled optical afterglows also show decays with flares and multiple
breaks. GRB 060526 provides an additional case of such a complex, well observed
optical afterglow. The accumulated well-sampled afterglows indicate that most
of the optical afterglows are complex.Comment: Accepted by ApJ, 21 pages, 4 figure