Why do galaxies cease forming stars? Evidence for AGN feedback driven quenching from cosmic dawn to the present epoch

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• Asa Bluck (Florida International University)
• Friday 19 July 2024, 11:30-12:30
• Ryle seminar room + online.

If you have a question about this talk, please contact Sandro Tacchella.

In the local Universe there is distinct bimodality observed in galaxy properties, such that most local systems are either actively star forming or non-star forming (‘quenched’). Quenched galaxies are now observed up to the first Gyr in the Universe’s history in unprecedented JWST observations. In this talk we identify the key testable predictions from AGN feedback driven quenching from contemporary cosmological models (e.g., EAGLE & IllustrisTNG). We then test these predictions across cosmic time with the SDSS & MaNGA (at z _{0), HST -CANDELS (at z} 0.5 – 2), and JWST -CEERS (at z ~ 2 – 8). Simulations predict that AGN feedback driven quenching will ultimately depend on the supermassive black hole (SMBH) mass, which directly traces the total integrated energy released from accretion over cosmic time. Crucially, little dependence on accretion rate or AGN luminosity is predicted by contemporary models. This has profound implications for the empirical study of quenching at all epochs. In lieu of dynamical measurements of SMBH masses for large statistical samples, the models predict that the galaxy central velocity dispersion or stellar potential should appear as the key driver of quiescence in machine learning classification analyses, which carefully remove spurious inter-correlations between galaxy properties. This prediction is met precisely across 13 Gyrs of cosmic history (from z = 0 – 8). Hence, we conclude that AGN feedback has likely been quenching star formation in massive galaxies since the first Gyr of the Universe’s history.

This talk is part of the Galaxies Discussion Group series.

This talk is included in these lists:

• Cambridge Astronomy Talks
• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Galaxies Discussion Group
• Institute of Astronomy Talk Lists
• Kavli Institute for Cosmology Talk Lists
• Ryle seminar room + online

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