Title:Searching for light echoes in type Ia supernovae spectra at late times

Abstract:
We search for the evidence of light echoes in type Ia supernovae (SNe Ia) spectra at late times (between 
35 to 85 days after maximum) due to interaction of the supernova light at maximum with circumstellar 
material in the vicinity of the explosion. It has previously been shown that SNe Ia have different broad-band 
color evolution at these later times suggesting possible light echoes (see Forster et al. 2013, accepted). 
We investigate here if differently extincted and reddened supernovae near maximum are indeed later 
affected spectroscopically by varying echo contributions.