Abstract
Over the past decade there have been many claimed detections of Ultra Fast Outflows (v>10,000 km/s) in X-ray spectra.  The inferred velocity, column density and distance of the UFOs translate into very large values of kinetic luminosity (sometimes rivaling the bolometric luminosity of the AGN itself). Therefore, these outflows, if real, are potentially important in the context of AGN feedback.  However, the empirical evidence for the existence of these UFOs continues to be weak and problematic even after a decade of intense studies, casting doubt on whether actual Ultra-Fast Outflows were ever detected in X-ray spectra.

Refreshments at 2:45pm

Talk host: Herman Marshall (if you would like to meet with Dr. Arav during his MIT visit, please contact Herman)