Aspherical Supernovae: Effects on Early Light Curves

• Main Authors: Afsariardchi, Niloufar, Matzner, Christopher D
• Format: Journal Article
• Language: English
• Published: 09-03-2018
• Subjects: Physics - High Energy Astrophysical Phenomena
• DOI: 10.48550/arxiv.1803.03646

Early light from core-collapse supernovae, now detectable in high-cadence
surveys, holds clues to a star and its environment just before it explodes.
However, effects that alter the early light have not been fully explored. We
highlight the possibility of non-radial flows at the time of shock breakout.
These develop in sufficiently non-spherical explosions if the progenitor is not
too diffuse. When they do develop, non-radial flows limit ejecta speeds and
cause ejecta-ejecta collisions. We explore these phenomena and their
observational implications, using global, axisymmetric, non-relativistic FLASH
simulations of simplified polytropic progenitors, which we scale to
representative stars. We develop a method to track photon production within the
ejecta, enabling us to estimate band-dependent light curves from adiabatic
simulations. Immediate breakout emission becomes hidden as an oblique flow
develops. Non-spherical effects lead the shock-heated ejecta to release a more
constant luminosity at a higher, evolving color temperature at early times,
effectively mixing breakout light with the early light curve. Collisions
between non-radial ejecta thermalize a small fraction of the explosion energy;
we address emission from these collisions in a subsequent paper.