NICER observation list: Target ID 674303

We propose to uncover the periodic signature of magnetars by observing the early afterglows of Swift GRBs. In particular we plan NICER observations of the X-ray plateau, a common early feature in the X-ray afterglows. During the plateau phase the decay of the lightcurve becomes shallower, and could be approximately constant for up to an hour. The plateau is possibly related to energy injection by magnetars that imprint periodic signatures on the lightcurve. If successful, NICER would probe the early (less than an hour after the GRB) afterglow using its unprecedented timing and spectral sensitivity opening up a new avenue to study GRB afterglows. Even a non-detection of periodicity would lead to the tightest constraints for the magnetar central engine.