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We present the results of a blind exercise to test the recoverability ofstellar rotation and differential rotation in Kepler light curves. Thesimulated light curves lasted 1000 days and included activity cycles, Sun-likebutterfly patterns, differential rotation and spot evolution. The range ofrotation periods, activity levels and spot lifetime were chosen to berepresentative of the Kepler data of solar like stars. Of the 1000 simulatedlight curves, 770 were injected into actual quiescent Kepler light curves tosimulate Kepler noise. The test also included five 1000-day segments of theSun's total irradiance variations at different points in the Sun's activitycycle.  Five teams took part in the blind exercise, plus two teams who participatedafter the content of the light curves had been released. The methods usedincluded Lomb-Scargle periodograms and variants thereof, auto-correlationfunction, and wavelet-based analyses, plus spot modelling to search fordifferential rotation. The results show that the `overall' period is wellrecovered for stars exhibiting low and moderate activity levels. Most teamsreported values within 10% of the true value in 70% of the cases. There was,however, little correlation between the reported and simulated values of thedifferential rotation shear, suggesting that differential rotation studiesbased on full-disk light curves alone need to be treated with caution, at leastfor solar-type stars.  The simulated light curves and associated parameters are available online forthe community to test their own methods.

Testing the recovery of stellar rotation signals from Kepler light curves using a blind hare-and-hounds exercise