Randall began his career studying the physics of the interstellar medium (ISM) at the University of Wisconsin-Madison. While there, he developed an interest in X-ray satellites, working to develop two proposals for X-ray microcalorimeter missions that eventually helped motivate US participation in the Suzaku and Hitomi missions. He is currently a Senior Astrophysicist at the Harvard-Smithsonian Center for Astrophysics, and has also spent a number of years working at the NASA/Goddard Space Flight Center.
His primary focus today is as PI of the proposed Arcus X-ray satellite, an X-ray grating spectrometry mission that would provide high-resolution spectra in the soft (12-50Å) bandpass. He also leads a group focused on collecting atomic data for X-ray spectroscopy (AtomDB).
On Athena, Randall is the US member of the Athena Science Study Team and co-chair of the Observatory Science Working Group, which covers a range of sources from the solar system, stars, supernova remnants, and - returning to his original interests - the ISM. He plans to use Athena to study how supernova remnants affect gas and dust in the ISM.
Link to the PDF version.
Image: The supernova remnant W44 in X-rays, with an overlay of the radio emission and some regions of interest marked.