Very High Energy Gamma Rays from the Vela Pulsar Direction

Abstract

We have observed the Vela pulsar region at TeV energies using the 3.8 m imaging Čerenkov telescope near Woomera, South Australia between 1993 January and 1995 March. Evidence of an unpulsed gamma-ray signal has been detected at the 5.8 σ level. The detected gamma-ray flux is (2.9 ± 0.5 ± 0.4) × 10-12photons cm-2s-1above 2.5 ± 1.0 TeV, and the signal is consistent with steady emission over the 2 years. The gamma-ray emission region is offset from the Vela pulsar position to the southeast by about 0°.13. No pulsed emission modulated with the pulsar period has been detected, and the 95% confidence flux upper limit to the pulsed emission from the pulsar is (3.7 ± 0.7) × 10-13photons cm-2s-1above 2.5 ± 1.0 TeV. © 1997. The American Astronomical Society. All rights reserved.