The Department of Physics and Astronomy and the Center for Simulational Physics will be hosting a joint colloquium this week. Dr. Phillip Stancil will be hosting Dr. Gary Ferland of the University of Kentucky. His talk is entitled "What powers the intra-cluster filaments in large clusters of galaxies?"

The first radio surveys of the sky discovered that some large clusters of galaxies contained powerful sources of synchrotron emission. Optical images showed that the intra-cluster medium was permeated by long linear filaments with bizarre emission line spectra. Recent observations in the infrared and radio show that these filaments have very strong emission lines of molecular hydrogen and carbon monoxide. The mass of molecular material is quite large, the gas is quite warm, and the filaments have not formed stars despite their multi-Gyr age. I will discuss the general astrophysical context of large clusters of galaxies and how large masses of molecular gas can be heated to produce what we observe.