Observations of Pulsar Wind Nebulae with the VERITAS Array of Imaging Atmospheric Cherenkov Telescopes

Abstract

Many of the recently discovered galactic very high-energy (VHE) gamma-ray sources are associated with Pulsar Wind Nebulae, which is the most populous Galactic source category at TeV energies. The extended synchrotron nebulae of these objects observed in the X-ray band are a hallmark of the relativistic winds, generated by the young, energetic neutron stars, that interact with the matter ejected by the supernova explosion and the surrounding interstellar gas. Relativistic electrons, or protons, accelerated in the pulsar winds, or at their shock boundaries, interact with the magnetic field and low energy seed photons to produce the observed VHE gamma-ray emission. The VERITAS array of four imaging atmospheric Cherenkov telescopes was designed to study astrophysical sources of gamma rays in the energy domain from about 100 GeV up to several tens of TeV. The sensitivity of the VERITAS array allows detailed studies of the morphology and spectral features of gamma-ray emission from PWNe. Three northern sky PWNe, G75.2+0.1, G106.6+2.9, and 3C58, were observed with VERITAS during 2006. No evidence for TeV gamma-ray emission at the position of the pu lsar associated with these PWNe is demonstrated.