We analyze a suite of 30 high resolution zoom-in cosmological hydrodynamic simulations of massive galaxies with stellar masses M∗>1010.9M⊙, with the goal of better understanding merger activity in AGN, AGN activity in merging systems, SMBH growth during mergers, and the role of gas content. Using the radiative transfer code \textsc{Powderday}, we generate HST-WFC3 F160W synthetic observations of redshift 0.5<z<3 central galaxies, add noise properties similar to the CANDELS survey, and measure morphological properties from the synthetic images using commonly adopted non-parametric statistics. We compare the distributions of morphological properties measured from the synthetic images with a sample of inactive galaxies and X-ray selected AGN hosts from CANDELS. We study the connection between mergers and AGN activity in the simulations, the synthetic images, and the observed CANDELS sample. We find that, in both the simulations and CANDELS, even the most luminous (Lbol>1045 erg s−1) AGN in our sample are no more likely than inactive galaxies (Lbol<1043 erg s−1) to be found in merging systems. We also find that AGN activity is not overall enhanced by mergers, nor enhanced at any specific time in the 1 Gyr preceding and following a merger. Even gas rich major mergers (stellar mass ratio >1:4) do not necessarily enhance AGN activity or significantly grow the central SMBH. We conclude that in the simulated massive galaxies studied here, mergers are not the primary drivers of AGN.
@article{arxiv.2101.01729,
title = {The Connection between Mergers and AGN Activity in Simulated and Observed Massive Galaxies},
author = {Ray S. Sharma and Ena Choi and Rachel S. Somerville and Gregory F. Snyder and Dale D. Kocevski and Michaela Hirschmann and Benjamin P. Moster and Thorsten Naab and Desika Narayanan and Jeremiah P. Ostriker and David J. Rosario},
journal= {arXiv preprint arXiv:2101.01729},
year = {2023}
}