Skillen.pdf (398.37 kB)

Searching for Helium Spectral Features in Type Ia Supernovae

Download (398.37 kB)
posted on 07.01.2020 by Skillen, Kelly
Although Type Ia supernovae (SNe Ia) are widely used as cosmological distance estimators, the progenitor systems which cause them are still relatively uncertain. One possibility is that a thin shell of Helium I surrounding the white dwarf detonates and triggers a secondary detonation in the carbon-oxygen core, creating a normal or sub-luminous SNe Ia in a double-detonation. It is theorised that a supernova caused by this progenitor model would show traces of Helium in its spectra around maximum light, particularly in the near-infrared region (NIR) around the He 10830 Å feature. However, this may be lost in lower resolution spectra due to blending with the Magnesium 10927 Å or the Carbon 10693 Å features. In this poster, we present the preliminary findings from an investigation into the NIR region of 30 SNe Ia intermediate-resolution spectra taken from XShooter on the European Southern Observatory's Very Large Telescope around B-band maximum light in the search of these He features.