Collaborative Research: Unravelling Stripped Supernovae - Synergy between Observations and Modeling

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

It has long been known that massive stars in the universe die in massive explosions known as supernovae (SNe). Supernovae resulting from the core collapse of massive stars are classified by astronomers in several ways. One type is normal SNe, whose massive progenitors have been stripped of their hydrogen and helium envelopes, thus known as “stripped supernovae.” Another type is classified as SNe Ic, with or without an accompanying gamma-ray burst (GRB), which emits relativistic jets of high-energy radiation. These explosions can be seen to large cosmological distances and are important for many fields of astrophysics. A research collaboration between the University of Virginia and Michigan State University will address some of the outstanding questions about SNe, such as which massive, stripped stars die in which kinds of deaths, and what is the detailed progenitor makeup for these explosions? The work will involve analyzing data from a large set of stripped SNe, as well as modeling those data and other published data via the open-source radiative transfer software called TARDIS, in combination with use of the machine-learning technology known as emulators for efficiently scanning large sets of parameters. In addition, to increase the number of members of underrepresented groups in STEM, the lead investigators will collaborate with two different programs (one, Girls Exploring the Universe, a summer program for middle school girls in Virginia, and the other at a high school in East Lansing, MI) to involve their students in different research projects that range from contributing to the TARDIS code to using the proposed widget that compares TARDIS simulations to recently observed SN spectra. Evidence suggests that school-age programs incorporating hands-on research, coding activities, and role models tend to increase self-confidence and interest of girls and minorities in STEM careers. The researchers aim to resolve two recent controversies in the SN community, with strong implications for stellar evolution, understanding the conditions needed for jet production, and for the hotly debated SN-GRB progenitor models. A clear understanding of the stellar progenitors and explosion parameters of SN and GRBs is an essential foundation for using them as indicators of star formation over cosmological distances and for assessing them as sources of re-ionizing the Universe. The proposed activities will transform the field of stripped SNe: they will quantify, for the first time, the systematic and statistical uncertainties in modeling these explosions and increase the total number of objects whose spectra have been modeled to at least 185 SNe, which constitutes the largest data set of Stripped SN in the world and allows the field to fully transition from individual objects to population studies. Moreover, the proposed framework will do so in a homogeneous and consistent manner. The proposed rapid and statistically solid theoretical interpretation framework will be made public. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.