Search for Pulsed TEV Gamma-Ray Emission from the Crab Pulsar
Abstract
We present the results of a search for pulsed TeV emission from the Crab pulsar using the Whipple Observatory's 10-m gamma-ray telescope. The direction of the Crab pulsar was observed for a total of 73.4 hr between 1994 November and 1997 March. During this period the Whipple 10 m telescope was operated at its lowest energy threshold to date. Spectral analysis techniques were applied to search for the presence of a gamma-ray signal from the Crab pulsar over the energy band 250 GeV to 4 TeV. We do not see any evidence of the 33 ms pulsations present in other energy bands from the Crab pulsar. The 99.9% confidence level upper limit for pulsed emission above 250 GeV is derived to be 4.8x10-12 cm-2 s-1 or less than 3% of the steady flux from the Crab Nebula. These results imply a sharp cutoff of the power-law spectrum seen by the EGRET instrument on the Compton Gamma-Ray Observatory. If the cutoff is exponential, it must begin at 60 GeV or lower to accommodate these upper limits.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2000
- DOI:
- 10.1086/308495
- arXiv:
- arXiv:astro-ph/9912520
- Bibcode:
- 2000ApJ...531..942L
- Keywords:
-
- GAMMA RAYS: OBSERVATIONS;
- STARS: PULSARS: INDIVIDUAL: NAME: CRAB PULSAR;
- Astrophysics
- E-Print:
- 20 pages including 6 figures, accepted for publication in the Astrophysical Journal