Back to Volume
Paper: Infrared Observations of the Crab Nebula
Volume: 271, Neutron Stars in Supernova Remnants
Page: 161
Authors: Gallant, Y. A.; Tuffs, R. J.
Abstract: The synchrotron emission of plerions has been investigated for the most part in the radio and X-ray domains; yet information at intermediate frequencies is essential to constrain the nature of spectral breaks. Observations in the optical are complicated by interstellar extinction in most cases, so that the infrared is the most favorable domain to observe plerions between radio and X-rays. We present the results of such observations of the Crab Nebula. We have obtained narrow-band continuum images of the Nebula at 16 and 6.4 microns with ISO, and at 2.2 microns from the ground, which we combine to derive spectral index maps, thus extending the optical work on spectral index variations of Veron-Cetty &Woltjer (1993). We show that the IR spectral index in the central parts of the Nebula is close to that in the radio, and gradually steepens outward. We argue that this harder IR spectral index marks the region where the radio-emitting electrons are accelerated, which is in the same central parts of the Nebula as for the higher-energy electrons.
Back to Volume