In Orbit Timing Calibration of the Suzaku Hard X-ray Detector

Suzaku is the fifth Japanese astrophysical satellite, devoted to study high energy phenomena in the X-ray band of 0.5 ? 600 keV. It was successfully launched from Uchinoura Space Center in Japan on 10th July 2005. The HXD on board Suzaku covers 10 ? 600 keV band with a high sensitivity of about 10?5 cnt/s/cm2/keV level. The sensor consists of 16 identical GSO/BGO well-type-phoswich counters incorporating 2 mm-thick silicon PIN diodes, and 20 surrounding-BGO-shield counters to remove residual non X-ray backgrounds through anti-coincidence rejection. The present paper is particularly focused on timing system of the HXD and in-orbit verifications with pulsars.