Constraining Type Ia Supernova Asymmetry with the Gamma-Ray Escape Timescale

Abstract

We calculate the effects of an asymmetric ${}^{56}\mathrm{Ni}$ distribution in Type Ia supernova (SN Ia) ejecta on the gamma-ray escape timescale ($t_0$) that characterizes the late light curve ($>40$ days after peak) and find the effect is modest compared to other possible variations in ejecta structure. We parameterize asymmetry in the ${}^{56}\mathrm{Ni}$ distribution and calculate $t_0$ for a grid of SN ejecta models spanning a large volume of the asymmetry parameter space. The models have spherical density profiles while the ${}^{56}\mathrm{Ni}$ distribution in them has various levels of asymmetry. By placing constraints based on the observational measurement of $t_0$ and other general properties of SN Ia ejecta, we find the range of allowed asymmetry in the ${}^{56}\mathrm{Ni}$ distribution. Considering these constraints we find that some level of asymmetry in the distribution is not ruled out. However, models with a single ejecta mass and varying ${}^{56}\mathrm{Ni}$ distributions cannot explain the full range of observed $t_0$ values. This strengthens the claim that both Chandrasekhar mass and sub-Chandrasekhar mass explosions are required to explain the diversity of SN Ia observations.

7 pages, 4 figures. Accepted to MNRAS

References in corpus (14)

• On the Origin of the Type Ia Supernova Width-Luminosity Relation
• The ejected mass distribution of type Ia supernovae: A significant rate of non-Chandrasekhar-mass progenitors
• Evidence for sub-Chandrasekhar-mass progenitors of Type Ia supernovae at the faint end of the width-luminosity relation
• Nebular spectra and abundance tomography of the type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core
• Early light curves for Type Ia supernova explosion models
• The fraction of type Ia supernovae exploding inside planetary nebulae (SNIPs)
• Predicting polarization signatures for double-detonation and delayed-detonation models of Type Ia supernovae
• Evidence for Sub-Chandrasekhar Mass Type Ia Supernovae from an Extensive Survey of Radiative Transfer Models
• Evaluating Systematic Dependencies of Type Ia Supernovae: The Influence of Central Density
• Explaining the early excess emission of the Type Ia supernova 2018oh by the interaction of the ejecta with disk-originated matter (DOM)
• Observational Characteristics and Possible Asphericity of Over-Luminous Type Ia Supernovae
• Swift, XMM-Newton, and NuSTAR observations of PSR J2032+4127/MT91 213
• Physical Structures of the Type Ia Supernova Remnant N103B
• An exact integral relation between the Ni56 mass and the bolometric light curve of a type Ia supernova

Cited by in corpus (2)

• Determining the ${}^{56}$Ni distribution of type Ia supernovae from observations within days of explosion
• Distribution of Si II $\lambda$6355 Velocities of Type Ia Supernovae and Implications for Asymmetric Explosions