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Astronomy Colloquium (2019 Fall Semester)

* Date
Oct. 31
* Speaker
Dr. Bernd Husemann (MPIA)
* Title
Characterizing multi-phase gas outflows and their powering mechanism in nearby AGN
* Abstract

Active Galactic Nuclei are thought to play a crucial role in the evolution of massive galaxies. In particular, fast outflows are frequently observed in AGN covering various gas phases which may remove a significant fraction of the gas content from the galaxies. I will review the current state of research in this very active field of ongoing research together with the advantages and disadvantages of previous approaches. In particular, I will highlight the importance of multi-wavelength observations to unravel the true multi-phase nature of outflows by combining state-of-the-art observational facilities. In this context I will present the first results from the ongoing Close AGN Reference Survey (CARS), a multi-wavelength survey of 39 luminous low-redshift unobscured AGN with extensive observations from VLT/MUSE, ALMA, VLA, Chandra, SOFIA and many more. So far we found a lack of hot gas as predicted by radiative wind scenarios, but a surprisingly strong [CII] excess in case of a powerful kpc size wind enriched with cold gas. Overall we find that more than 50% of the high-velocity outflows are very compact <100pc and that the radio jets likely play an important role as a driving mechanisms for these massive multi-phase outflows from AGN.