USING THE 1.64 MICRON [FeII] EMISSION LINE TO DETECT SUPERNOVA REMNANTS IN NGC 6946

In the infrared (IR), shock models indicate, and observations show that supernova remnants (SNRs) emit strongly in [Fe II] at 1.64 μm. This thesis reports the results of a search for SNRs in NGC 6946 relying on [Fe II] 1.64 μm line emission, where we employed an adjacent [Fe II]Off filter to accurately assess the local continuum levels. In this study, we used the WIYN High Resolution Infrared Camera (WHIRC) on the WIYN 3.5m telescope to image NGC 6946 in broad bands J and H and narrow bands [Fe II], [Fe II]Off, Paβ and PaβOff. From our search, we have identified 72 supernova remnant candidates (SNRcs), 11 of which are coincident with sources found in prior radio, optical and/or x-ray studies. Six of the 11 coincident sources were specifically classified as SNRs in their respective studies. The measured [Fe II] luminosities of our SNRcs range from 4.02×10^35 to 2.09×10^37 erg s^−1 and are among the highest of previously published extragalactic SNR [Fe II] luminosities. Using the measured [Fe II] luminosities, we calculate an estimated SN rate of 0.078 yr^−1 for NGC 6946, which is comparable to the observed rate in the last 100 years of 0.09 yr^−1. We also compare our SNR candidates with SNRs that have been found at radio, optical and X-ray wavelengths. All of the candidates now need to be confirmed spectroscopically. However, the fact that we detect as many objects as we did, suggests that [Fe II] can be used as an effective search tool to find extragalactic SNRs