Description
MIT Astrophysicist and Lexingtonian, Dr. Herman Marshall will show how we try to understand the environments of black holes using high resolution imaging and spectroscopy obtained with the Chandra X-ray Observatory and polarimetry using the Imaging X-ray Polarimetry Explorer. Each method elucidates different aspects of black hole systems, from “stellar mass” black holes in binaries within the Milky Way galaxy to supermassive black holes in the nuclei of active galaxies. Imaging shows relativistically moving jets of plasma that are highly collimated, disrupt star formation in their host galaxies, and extend to distances well outside their host galaxies. Spectroscopy can be used to measure the spins of Galactic black holes and examine rapidly outflowing plasma. Polarimetry results from electrons moving in strong magnetic fields, giving the orientation of such fields in active galactic jets and also results from scattering that provides a geometric diagnostic. Finally, I will introduce a new kind of X-ray polarimeter in development at MIT, called the Rocket Experiment Demonstration of a Soft X-ray Polarimeter, aka REDSoX.
Dr. Herman Marshall is a Principal Research Scientist at the MIT Kavli Institute for Astrophysics and Space Research. He is Associate Director of the Chandra X-ray Center that operates the Chandra X-ray Observatory and is the calibration scientist for the High Energy Transmission Grating instrument on Chandra. He also leads a sounding rocket instrument development project called the Rocket Experiment Demonstration of a Soft X-ray Polarimeter, aka REDSoX. A follow-on experiment, the Globe Orbiting Soft X-ray Polarimeter (GOSoX) is in a pre-funding stage. He is co-Investigator on NASA’s Imaging X-ray Polarimetry Explorer. Previously, he was lead scientist on the software development for the Extreme Ultraviolet Explorer project at the University of California, Berkeley and a postdoctoral fellow at the Space Telescope Science Institute. He obtained his Ph.D. in Astronomy from Harvard University in 1983 and his S.B. from MIT in 1978. His research interests include high resolution X-ray spectroscopy of active galaxies and neutron stars, imaging quasar jets, high resolution X-ray imaging, and X-ray polarimetry
