Short time scale pulse stability of the Crab pulsar in the optical band

Abstract

The fine structure and the variations of the optical pulse shape and phase of the Crab pulsar are studied on various time scales. The observations have been carried out on 4-m William Hershel and 6-m BTA telescopes with APD photon counter, photomultiplier based 4-channel photometer and PSD based panoramic spectrophotopolarimeter with 1$\mu$s time resolution in 1994, 1999, 2003 and 2005-2006 years. The upper limit on the pulsar precession on Dec 2, 1999 is placed in the 10 s - 2 hours time range. The evidence of a varying from set to set fine structure of the main pulse is found in the 1999 and 2003 years data. No such fine structure is detected in the integral pulse shape of 1994, 1999 and 2003 years. The drastic change of the pulse shape in the 2005-2006 years set is detected along with the pulse shape variability and quasi-periodic phase shifts.

arXiv comment4 pages, 6 figures. To appear in ApSS, in the proceedings of the conference "Isolated Neutron Stars: from the Interior to the Surface", London, April 2006; eds. D. Page, R. Turolla and S. Zane

References in corpus (5)

• Gamma Ray Pulsars: Emission from Extended Polar Cap Cascades
• Enhanced Optical Emission During Crab Giant Radio Pulses
• Position-sensitive detector for the 6-meter optical telescope
• The Multicolor Panoramic Photometer-Polarimeter with high time resolution based on the PSD
• Crab Pulsar Photometry and the Signature of Free Precession

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• Study of the High Energy Gamma-ray Emission from the Crab Pulsar with the MAGIC telescope and Fermi-LAT
• Optical photon-counting observation of the Crab pulsar with Kanata telescope using prototype IMONY
• One-week optical observations of pulsed emission from the Crab pulsar with IMONY on the 3.8 m Seimei telescope