Colloq Abstract - Fesen

October 20, 2023

11:00am Mountain

Rob Fesen (Dartmouth)

 

The Synergy of Radio and Optical Surveys for Discovering Galactic Supernova Remnants

 

Abstract

The vast majority of the roughly 300 currently known Galactic supernova remnants (SNRs) have been discovered through radio observations via detection of nonthermal radio emissions.  Recent deep radio studies of the MW's plane have detected a few dozen more Galactic remnants. But these studies are unlikely to resolve the large discrepancy between the 300 remnants known and the roughly 500 to 1000 theoretically expected.  Despite the fact that less than half of the already known remnants show any detectable levels of optical emission, recent wide field optical surveys have uncovered a surprising number of new remnants, some of which are very large  (dia: 5-20 degrees), located well off the galactic plane, and not radio bright. Moreover, several show unexpectantly strong [OIII] emissions but relatively weak Halpha emissions indicative of moderately fast ISM shocks (100-150 km/s). I will discuss how these new optical SNRs are being discovered but missed in the radio and how future combined radio and optical SNR surveys can generate a more complete picture of Galactic SNRs.

 

Local Host: Justin Linford

 

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