Schedule Aug 21, 2009
Exploring Correlations between NIR Spectra and the Brightness of Type Ia Supernovae
Howie Marion (U Texas/TAMU)

We compare measurements of absorption features in a sample of 35 near infrared (NIR) spectra from Type Ia supernovae (SNe) and the intrinsic brightness of the of the supernovae as characterized by the light curve parameter Δm15(B). We find that the line depths of OI and MgII features become deeper as Δm15(B) increases. Thus spectra from faster declining (intrinsically dimmer) SNe Ia display stronger signatures of OI and MgII than found in spectra from slower decliners. CaII absorption does not exhibit this correlation. OI and MgII are nuclear burning products created under burning conditions of lower temperatures and densities such as may be found in the outer layers of the progenitor. The spectra in this sample were obtained between -11d and +6d with respect to T(Bmax) during which time a SN Ia has a well defined photosphere in the outer layers of the explosion envelope.

Author entry (protected)