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Unveiling the Rate and Nature of Dual AGN

Adi Foord (Stanford/KIPAC)

April 20 @ 12:00 PM - 1:00 PM

Massive black hole pairs at kiloparsec scales are expected as a result of massive galaxy mergers — and if sufficient levels of gas are efficiently funneled into the central active regions, one may expect a large fraction of AGN pairs. The ongoing search for AGN pairs has spanned over 25 years, via a wide range of multi-wavelength techniques. X-ray, optical, and radio analyses have been carried out, using both indirect and direct detection techniques, for various sources. However, to date, the number of confirmed AGN pairs remains relatively small; AGN pairs that are widely separated relative to the instrument PSF and have near unity flux ratios are easy to identify, but those with small separations and/or flux ratios are more difficult to detect. The small number of confirmed pairs, the majority of which have large (> 1 kpc) separations, has limited our understanding of the role galaxy mergers play in AGN activation and the dependence of AGN activity on the surrounding environment. In the following talk I’ll review recent progress to detect AGN pairs in X-ray observations, where statistical analyses with BAYMAX (Bayesian AnalYsis of Multiple AGN in X-rays) allows for identification of closely separated and/or faint AGN pairs across a large range of redshift.  Additionally, combining X-ray results with available optical and IR observations allows for better insight on preferential environments of AGN pairs. Most importantly, finding more AGN pairs across a range of separations in the local universe will lead to a constraint on the gravitational wave rate, as expected to be detected by Pulsar Timing Arrays and LISA.

Please contact the department office for Zoom information.