Optical Tomography of Chemical Elements Synthesized in Type Ia Supernovae

: We report the discovery of optical emission from the nonradiative shocked ejecta of three young type Ia supernova remnants (SNRs): SNR 0519-69.0, SNR 0509-67.5, and N103B. Deep integral field spectroscopic observations reveal broad and spatially resolved [Fe XIV] 5303 A emission. The width of the broad line reveals, for the first time, the reverse shock speeds. For two of the remnants we can constrain the underlying supernova explosions with evolutionary models. SNR 0519-69.0 is well explained by a standard near-Chandrasekhar mass explosion, whereas for SNR 0509-67.5 our analysis suggests an energetic sub-Chandrasekhar mass explosion. With [S XII], [Fe IX], and [Fe XV] also detected, we can uniquely visualize different layers of the explosion. We refer to this new analysis technique as "supernova remnant tomography".