Astro Seminar Series - VIA ZOOM

Dr. Christopher O’Dea received a BS in Physics from MIT and a PhD in Astronomy from University of Massachusetts, Amherst. He held postdoctoral positions at the National Radio Astronomy Observatory and the Netherlands Foundation for Research in Astronomy, and faculty positions at STScI and Rochester Institute of Technology, and is currently Professor of Physics & Astronomy at University of Manitoba. Dr. O’Dea conducts multi-wavelength observations of Active Galactic Nuclei in order to understand their triggering, evolution, life cycles, and effect on their environments. He has studied variability of quasars and blazars,  narrow-angle tail radio sources in clusters,  propagation of radio jets, young radio sources, star formation and feedback in galaxies and cool core clusters, and ionized outflows from AGN.

Talk Title and Abstract:

What are the Compact, Powerful, Extragalactic Radio Sources?

 Compact, powerful extragalactic radio sources are defined to have linear sizes < 20 kpc and so are sub-galactic in scale. These sources might be very young radio galaxies which will evolve into large radio galaxies. Or, the compact sources might be compact because they are confined (and enhanced in radio power) by interaction with dense gas in their environments.  Alternately, the compact sources might be transient or intermittent sources. Each of these hypotheses may apply to individual objects. The relative number in each population will have significant implications for the Active Galactic Nuclei (AGN) paradigm. Proper motion studies over long time baselines have helped determine hotspot speeds for over three dozen sources and establish that some objects are young. Multi-frequency observations have demonstrated that many compact sources are embedded in a dense interstellar medium and vigorously interacting with it. The detection of emission line gas aligned with the radio source, and blue-shifted HI absorption and [OIII] emission lines indicates that AGN feedback is present in these objects -- likely driven by the radio source.

Would you like to join this Zoom seminar?  Please email Donna Hayes.