Crab pulsar photometry and the signature of free precession
Department of Physics, FMF University in Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia I.N.A.O.E., Luis Enrique Erro 1, Tonantzintla, Puebla 72840, Mexico
Corresponding author: A. Čadež, firstname.lastname@example.org
Accepted: 16 November 2000
Optical photometry for the pulsar PSR 0531+21 has been extended with new observations that strengthen evidence for a previously observed 60 s periodicity. This period is found to be increasing with time at approximately the same rate as the rotational period of the pulsar. The observed period and its time dependence fit a simple free precession model.
Key words: stars: neutron / pulsars: individual: PSR 0531+21 / rotation / oscillations
© ESO, 2001