Timing analysis of the core of the Crab-like SNR G21.5-0.9

The Crab-like SNR G21.5-0.9 was observed in the X-ray band (0.5-10 keV) by the XMM-Newton satellite for over 100 ks. The large e ective area of the EPIC instrument has allowed us to perform a deep search for pulsations from the central core of G21.5-0.9. No pulsations were found with upper limits on the pulsed fraction between 7.5% and 40% (depending on frequency and energy range).