Search for Pulsed TeV Gamma-ray Emission from the Crab Pulsar

R. W. Lessard; I. H. Bond; S. M. Bradbury; J. H. Buckley; A. M. Burdett; D. A. Carter-Lewis; M. Catanese; M. F. Cawley; M. D'Vali; D. J. Fegan; J. P. Finley; J. A. Gaidos; G. H. Gillanders; T. Hall; A. M. Hillas; F. Krennrich; M. J. Lang; C. Masterson; P. Moriarty; J. Quinn; H. J. Rose; F. W. Samuelson; G. H. Sembroski; R. Srinivasan; V. V. Vassiliev; T. C. Weekes

doi:10.1086/308495

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arXiv · astro-ph/9912520

Search for Pulsed TeV Gamma-ray Emission from the Crab Pulsar

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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 hours 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 <3% of the steady flux from the Crab Nebula. These results imply a sharp cut-off of the power-law spectrum seen by the EGRET instrument on the Compton Gamma-Ray Observatory. If the cut-off is exponential, it must begin at 60 GeV or lower to accommodate these upper limits.

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R. W. Lessard, I. H. Bond, S. M. Bradbury, J. H. Buckley, A. M. Burdett, D. A. Carter-Lewis, M. Catanese, M. F. Cawley, M. D'Vali, D. J. Fegan, J. P. Finley, J. A. Gaidos, G. H. Gillanders, T. Hall, A. M. Hillas, F. Krennrich, M. J. Lang, C. Masterson, P. Moriarty, J. Quinn, H. J. Rose, F. W. Samuelson, G. H. Sembroski, R. Srinivasan, V. V. Vassiliev, T. C. Weekes. 1999-12-27. Search for Pulsed TeV Gamma-ray Emission from the Crab Pulsar. https://doi.org/10.1086/308495

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