Astronomy and Astrophysics Seminars

Cool Core Cycles - Cold-mode AGN feedback in Galaxies, Groups and Clusters

by Dr. Deovrat Prasad (Cardiff University)

Tuesday, September 27, 2022 from to (Asia/Kolkata)
at Hybrid ( AG 66 ) Meeting ID: 918 9636 7025 Passcode: 802111
Galaxy clusters are the largest known gravitationally bound objects of the universe. Their gravitational mass is dominated by dark matter with baryons accounting only for about 15% of the total mass. About a quarter of the total baryons in a galaxy cluster is in the form of stellar matter of the member galaxies while the rest are in the form of hot diffused plasma pervading the space between the galaxies called intra-cluster medium (ICM). In  about 1/3 to 1/2 of the galaxy clusters called cool-core clusters,  the ICM is relaxed and gravitationally stratified with cooling time of the plasma smaller than the lifetime of these clusters. In such systems precipitation of cold gas from the hot ICM and their subsequent infall and accretion onto supermassive black holes located in the central galaxy of the galaxy clusters fuels outbursts of powerful jets called active galactic nuclei (AGN). AGN outbursts are powerful enough to compensate for the cooling losses of the gas in ICM and regulate the star formation rate. In my talk, I will discuss the radiative cooling-feedback heating cycles in massive  galaxies, groups and clusters. I will also talk about some of the recent observations of ICM-AGN interaction in the most massive galaxy clusters like Phoenix and where do they fit in the standard AGN feedback scenario. Another major topic I will discuss is the role of galactic environmental factors on the ability of AGN feedback to self-regulate in smaller halos like giant elliptical galaxies and galaxy groups. Finally, I will touch upon some of the ongoing and future projects I am engaged in.
Organised by DAA