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C.K. Lacey (NRL/NRC), N. Kassim (NRL), N. Duric (UNM)
Low frequencies provide a unique opportunity to study steep spectrum sources, such as supernova remnants (SNRs). SNRs profoundly affect the interstellar medium (ISM) through shock interaction, kinetic energy input, particle acceleration, and enrichment of the ISM. In addition, at lower frequencies absorption effects from both internal and external sources can be studied. We present preliminary results of VLA 74 MHz imaging of the Galactic SNR W49B. The spectrum of W49B has a known turnover at low frequencies determined from total integrated flux. This new 74 MHz image has ~ 25\arcsec\ angular resolution, which can now be compared to other images at different frequencies in order to understand the physical mechanism(s) behind the observed turnover. The images of W49B (74 and 330 MHz) are compared and the differences in morphology between the two images and the physical implications are discussed.
The author(s) of this abstract have provided an email address for comments about the abstract: lacey@rsd.nrl.navy.mil