Galaxy Clusters

My Research

Supernova Remnants

Galaxy clusters are complex physical objects, consisting of several interacting components: dark matter, the intracluster medium (ICM), and individual galaxies.  Passive evolution of these components, including radiative cooling of the ICM, feedback between a central AGN and the ICM, and enrichment of the ICM by the galaxies, as well as cluster-cluster interactions and mergers lead to a wealth of substructure in the ICM, such as X-ray cavities, cool cores, shocks, and cold fronts, some of which can be seen below.  Understanding this substructure and its relation to other cluster properties is critical for understanding cluster formation and evolution.  In addition, temperature substructure affects the mass - observable scaling relations which play a pivotal role in constraining cosmological parameters.  To investigate the temperature structure of clusters, I apply an innovative analysis technique in order to measure the amount of gas at different temperatures within the ICM. 

Supernova remnants are invaluable tools for studying stellar evolution, supernovae, and the interstellar medium. Massive progenitor stars host strong stellar winds which change as the star evolves, leaving behind material which is later probed by the supernova remnant (SNR) as it expands in this circumstellar medium (CSM). The abundances of heavy elements in the SNR are also tied to both the stellar evolution of the progenitor and the supernova explosion mechanism. As a SNR expands into the interstellar medium (ISM), the shock probes the ambient medium and heavy elements are injected into the surrounding ISM. The shocks also heat the medium through which they travel to X-ray emitting temperatures. As a result, X-rays generally provide the best band for probing the bulk of the remnant, including the ejected remnants of the progenitor star. Work over the past two decades with X-ray observations from ASCA, Chandra, XMM-Newton, and Suzaku has revealed the extremely complicated nature of supernova remnants, and how much we have yet to learn.