English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We calculate the effects of an asymmetric $^{56}\mathrm{Ni}$ distribution inType Ia supernova (SN Ia) ejecta on the gamma-ray escape timescale ($t_0$) thatcharacterizes the late light curve ($>40$ days after peak) and find the effectis modest compared to other possible variations in ejecta structure. Weparameterize asymmetry in the $^{56}\mathrm{Ni}$ distribution and calculate$t_0$ for a grid of SN ejecta models spanning a large volume of the asymmetryparameter space. The models have spherical density profiles while the$^{56}\mathrm{Ni}$ distribution in them has various levels of asymmetry. Byplacing constraints based on the observational measurement of $t_0$ and othergeneral properties of SN Ia ejecta, we find the range of allowed asymmetry inthe $^{56}\mathrm{Ni}$ distribution. Considering these constraints we find thatsome level of asymmetry in the distribution is not ruled out. However, modelswith a single ejecta mass and varying $^{56}\mathrm{Ni}$ distributions cannotexplain the full range of observed $t_0$ values. This strengthens the claimthat both Chandrasekhar mass and sub-Chandrasekhar mass explosions are requiredto explain the diversity of SN Ia observations.

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