Hubble Fellow @ MIT
Speaking at 2013 Hubble Fellows Symposium at STScI (Mar, 5, 2013)
Recently published ApJ letter presenting HST imaging of the Phoenix Cluster here! (Feb 2013)
mcdonald "at" space.mit.edu
Composite image of the filamentary complex in Abell 1795. (Yellow: Red continuum, old stellar populations; Red: MMTF Hα, warm ionized gas; Blue: HST far-UV, young stellar populations). This complex multiphase system is most likely the result of runaway cooling in the hot, intracluster plasma.
My current research is focused on understanding heating and cooling processes in the cores of galaxy clusters. By necessity, this work requires use of a wide variety of data, including X-ray, UV, optical, IR, sub-mm, and radio observations. In collaboration with the South Pole Telescope (SPT) team, I am trying to understand the evolution of a sample of massive, SZ-selected galaxy clusters. This nearly redshift independent sample is proving to be invaluable for studying the evolution of the hot, intracluster medium.
For my PhD thesis, I used the Maryland-Magellan Tunable Filter to examine heating and cooling processes in galaxy groups and clusters, primarily by looking for extended Hα emission. The exquisite resolution (DIQ ~ 0.5") of these data allows us to resolve structure which was previously unknown, such as the intertwined filaments in Abell 1795 (left). By combining the emission-line data with existing Chandra and GALEX observations, as well as new HST observations in the far-UV, we shed new light on these mysterious structures.
For our results, see my publications.
|The "Markarian Chain" in the Virgo Cluster||For my MSc. thesis,
I conducted a near-IR (H-band) survey of the Virgo cluster with
Stephane Courteau (Queen's University) and Brent Tully (University of
Hawaii). We obtained optical and H-band photometry for a complete sample
of 293 Virgo cluster galaxies which we used to perform a detailed
analysis on the structural properties of these galaxies via bulge-disk
The exciting results of this extensive study have been accepted for publication in MNRAS.