Esin, Ann A.Kuulkers, ErikMcClintock, Jeffrey E.Narayan, Ramesh2019-09-222000Esin, Ann A., Erik Kuulkers, Jeffrey E. McClintock, and Ramesh Narayan. 2000. “Optical Light Curves of the Black Hole Binaries GRS 1124−68 and A0620−00 in Outburst: The Importance of Irradiation.” The Astrophysical Journal 532 (2): 1069–77. https://doi.org/10.1086/308615.0004-637X1538-4357http://nrs.harvard.edu/urn-3:HUL.InstRepos:41384928We test whether the model proposed by Esin ct al. to explain X-ray observations of the black hole soft X-ray transient GRS 1124-68 in outburst can also explain the optical light curves of a similar object, A0620-00. We show that to reproduce the observed X-ray to optical flux ratio in A0620-00, we need to assume X-ray irradiation of the outer disk that is significantly in excess of what is expected for a standard planar disk. With enhanced irradiation, the Esin et al. model can reproduce the optical evolution of A0620-00 in outburst very well. Though we find that optical observations of GRS 1124-68 also imply enhanced X-ray heating of the outer disk, the irradiation appears to be a factor of similar to 3 weaker in this system than in A0620-00. This is surprising, since GRS 1124-68 has a larger disk. We speculate that enhanced irradiation may be due to disk warping, and that the degree of warping differs between the two binaries.en-USJournal Article2019-09-2210.1086/308615