Utilizing Supernova Remnant Dynamics and Environments to Probe Core-Collapse Explosions

John Banovetz, Purdue University

Abstract

Core-collapse supernovae are among the most consequential astronomical events. They impact galaxy evolution, chemical enrichment of the Universe, and the creation of exotic objects (e.g., black holes and neutron stars). However, aspects of supernovae such as explosion asymmetry and progenitor mass loss are not well understood. Young, nearby supernova remnants are excellent laboratories to uniquely constrain some these fundamental properties. In this thesis, I investigate two nearby oxygen-rich supernova remnants and measure the proper motion of their ejecta to estimate their center of expansions and explosion ages. These properties are important for determining central compact object ‘kick’ velocities, guiding searches for surviving companions, and creating 3D remnant reconstructions.I estimate the center of expansion and age of two supernova remnants, 1E0102.2-7219 (E0102) and N132D utilizing two epochs of Hubble Space Telescope imaging to measure the proper motion of their ejecta. For E0102, the proper motions show evidence for a nonhomologous expansion, which combined with spectral observations, support the idea that this remnant is expanding into an asymmetric circumstellar environment. Using the new proper-motion derived age and center of expansion, I provide a new ‘kick’ velocity estimate for E0102’s candidate neutron star. For N132D, I measure the proper motion of the ejecta both visually and using a novel computer vision procedure which identifies and measures the proper motions of the knots. I find that N132D’s ejecta are still ballistic, along with evidence of explosion asymmetry. My results represent the first proper-motion derived center of expansion and age of N132D.Finally, I investigate diffuse interstellar bands observed towards progenitor candidates of core-collapse supernovae to test whether time variability can be a possible probe of the mass loss and surrounding environments of these systems. I find evidence of time variability in diffuse interstellar band carriers located in two of these environments. This is especially unusual as diffuse interstellar bands are normally attributed to the interstellar medium. These findings imply that the sources of these bands are closer to the stellar objects than previously thought and can provide insight into the currently unknown sources of diffuse interstellar bands.

Degree

Ph.D.

Advisors

Milisavljevic, Purdue University.

Subject Area

Astronomy|Astrophysics|Atomic physics|Optics|Physics

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