This talk was part of the UH Centre for Astrophysics Research (CAR) 2023-2024 seminar series. For the ongoing programme, please see: https://www.herts.ac.uk/research/cent...

Date: 8 Oct 2023
Speaker: Izzy Garland – Lancaster University
Title: Merger-Free Co-evolution of SMBH and their Host Galaxies.

Abstract: Galaxies and their supermassive black holes are known to co-evolve, and this is shown via a number of relations. However, the drivers of this co-evolution are not well understood. Mergers between two or more galaxies have been shown to be one pathway, thought for many years to be the dominant pathway, but recently it has been shown that most black hole growth occurs in the absence of major mergers. I will talk about my contributions to this field, first using a sample of luminous, Type 1 AGN hosted in galaxies which have not experienced any major mergers since redshift 2 to investigate merger-free black hole growth, with a particular focus on the effect of large-scale galactic bars. We find that the bar fraction in our AGN hosts is marginally higher (fbar = 59 ± 9 %) than in a well-matched sample of merger-free galaxies lacking an AGN (fbar = 44 ± 9 %). I will then move onto my work using DESI to investigate the variation AGN prominence with bar strength in disk dominated galaxies. We find that strongly barred galaxies are more likely to host AGN than weakly barred galaxies, which are in turn more likely to host AGN than unbarred galaxies at all stellar masses and colours.