Echoes of Silence: Probing Type Ia Supernovae Environments with Scattered Light Echoes


Fri, 19 Feb 2021, 03:00 pm - 04:00 pm
Spring 2021
Dr. Charlotte Wood
Notre Dame


Type Ia supernovae (SNe Ia) are powerful distance indicators for cosmology because of their extreme and consistent luminosities, however the exact mechanism behind the explosion remains an open question. In order to better understand SNe Ia and improve our cosmological parameters, we need a method to distinguish between progenitor types and to characterize the local environment of individual SNe Ia. A powerful way to achieve both is through light echoes. Three-dimensional maps of the dust distribution around SNe Ia, as revealed by light echoes, can provide insight into the progenitor of the system: compact, disk-like echoes are likely caused by circumstellar material. Multi-color imaging of light echoes can also reveal properties of the dust in the local environment (e.g. dust grain size, distribution, and chemical composition). We can infer the existence of a light echo from late-time photometry of a supernova, but in order to map out the dust distribution, the light echo must be resolved. Here I present a newly identified light echo around SN 2009ig, first inferred from the late-time light curve form the Large Binocular Telescope and now resolved in archival Hubble Space Telescope images, and what we can learn about the local environment of this SN Ia.

Charlotte M. Wood is a fifth-year PhD candidate at the University of Notre Dame. She works with Dr. Peter Garnavich studying type Ia supernova cosmology, light echoes, and compact binary systems. Her thesis focuses on determining type Ia progenitor types through light echoes and how the relative rate of progenitor types affects Hubble constant measurements. Previously she worked with Dr. Justin Crepp characterizing directly imaged brown dwarfs and their stellar companions. Charlotte received her Bachelor of Science in Physics from Hofstra University in 2016, where she worked with Dr. Stephen Lawrence studying light echoes and recurrent novae. She will be on the job market next year looking for postdoctoral positions.