Polarization spectral synthesis for Type Ia supernova explosion models

M. Bulla*, S. A. Sim, M. Kromer

*Corresponding author for this work

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

We present a Monte Carlo radiative transfer technique for calculating synthetic spectropolarimetry for multidimensional supernova explosion models. The approach utilizes 'virtual-packets' that are generated during the propagation of the Monte Carlo quanta and used to compute synthetic observables for specific observer orientations. Compared to extracting synthetic observables by direct binning of emergent Monte Carlo quanta, this virtual-packet approach leads to a substantial reduction in the Monte Carlo noise. This is not only vital for calculating synthetic spectropolarimetry (since the degree of polarization is typically very small) but also useful for calculations of light curves and spectra. We first validate our approach via application of an idealized test code to simple geometries. We then describe its implementation in the Monte Carlo radiative transfer code ARTIS and present test calculations for simple models for Type Ia supernovae. Specifically, we use the well-known one-dimensional W7 model to verify that our scheme can accurately recover zero polarization from a spherical model, and to demonstrate the reduction in Monte Carlo noise compared to a simple packet-binning approach. To investigate the impact of aspherical ejecta on the polarization spectra, we then use ARTIS to calculate synthetic observables for prolate and oblate ellipsoidal models with Type Ia supernova compositions.

Original languageEnglish
Pages (from-to)967-981
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume450
Issue number1
DOIs
Publication statusPublished - 11 Jun 2015

Keywords

  • polarization
  • radiative transfer
  • methods: numerical
  • supernovae: general
  • GRAVITATIONALLY CONFINED DETONATION
  • CHANDRASEKHAR MASS MODELS
  • WHITE-DWARF MERGERS
  • CARLO RADIATIVE-TRANSFER
  • DELAYED-DETONATION
  • LIGHT CURVES
  • CARBON DEFLAGRATION
  • VIOLENT MERGERS
  • SPECTROPOLARIMETRY
  • SCATTERING

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