Spectral analysis of the 91bg-like Type Ia SN 2005bl: Low luminosity, low velocities, incomplete burning - Astrophysics > High Energy Astrophysical PhenomenaReport as inadecuate




Spectral analysis of the 91bg-like Type Ia SN 2005bl: Low luminosity, low velocities, incomplete burning - Astrophysics > High Energy Astrophysical Phenomena - Download this document for free, or read online. Document in PDF available to download.

Abstract: The properties of underluminous type Ia supernovae SNe Ia of the 91bgsubclass have yet to be theoretically understood. Here, we take a closer lookat the structure of the dim SN Ia 2005bl. We infer the abundance and densityprofiles needed to reproduce the observed spectral evolution between -6 d and+12.9 d with respect to B maximum. Initially, we assume the density structureof the standard explosion model W7; then we test whether better fits to theobserved spectra can be obtained using modified density profiles with differenttotal masses and kinetic energies. Compared to normal SNe Ia, we find a lack ofburning products especially in the rapidly-expanding outer layers v>~15000km-s. The zone between ~8500 and 15000 km-s is dominated by oxygen andincludes some amount of intermediate mass elements. At lower velocities,intermediate mass elements dominate. This holds down to the lowest zonesinvestigated in this work. This fact, together with negligible-to-moderateabundances of Fe-group elements, indicates large-scale incomplete Si burning orexplosive O burning, possibly in a detonation at low densities. Consistentlywith the reduced nucleosynthesis, we find hints of a kinetic energy lower thanthat of a canonical SN Ia: The spectra strongly favour reduced densities at>~13000 km-s compared to W7, and are very well fitted using a rescaled W7 modelwith original mass 1.38 M sun, but a kinetic energy reduced by ~30 % i.e.from 1.33e51 erg to 0.93e51 erg.



Author: Stephan Hachinger, Paolo A. Mazzali, Stefan Taubenberger, Ruediger Pakmor, Wolfgang Hillebrandt

Source: https://arxiv.org/







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