Hot Spot Emission from a Freely Precessing Neutron Star

Recent observations of 1E~161348-5055, the neutron-star candidate at thecenter of the supernova remnant RCW 103, show that a component of its emissionvaries sinusoidally with a period of approximately six hours. We argue thatthis period is what one would expect for a freely precessing neutron star witha spin period of about one second. We produce light curves for a freelyprecessing neutron star with a hotspot. By a suitable choice of parameters, weobtain light curves which are constant with rotational phase when the flux fromthe star reaches a maximum. At other phases of the precession, the flux variesas the star rotates but the total flux decreases by a factor of several. Thesemodels can explain the behavior observed from 1E~161348-5055 and predict thatthe spin period should be detectable at minimum flux from sufficientlysensitive measurements.