A Walk through AGN Country—For the Somewhat Initiated!

Abstract

Key issues in AGN and galaxy formation are discussed. Very successful Unified Models explain much of the variety of AGN with orientation effects; the ingredients are shadowing by a dusty “torus” and relativistic beaming. A spinoff result is described which is important for the formation of massive elliptical galaxies, the most spectacular and unequivocal AGN feedback phenomenon known. This is the so-called “alignment effect” in powerful radio galaxies at z∼>1. One of them is a BAL radio galaxy! Next, I explain a very robust derivation of the reddening law for nuclear dust, which reveals a dearth of small grains on parsec scales. Then, the quasistatic thin accretion disk model, thought by many to explain the energetically dominant optical/UV continuum, is thoroughly debunked. Much of this was known when the model was proposed 35 years ago. A new argument is provided that trivially falsifies a huge superset of such models. I then show that it is possible to see the central engine spectrum with the atomic and dust emission surgically removed! Few have noticed this breakthrough work. Finally, the far IR dust emission in Cygnus A is 10% polarized; to date, high nuclear dust polarization has been seen in all radio loud objects and no radio quiet ones.

Simulating X-Ray Reverberation in the Ultraviolet-emitting Regions of Active Galactic Nuclei Accretion Disks with Three-dimensional Multifrequency Radiation Magnetohydrodynamic Simulations

“…Increasing our understanding of the physical processes that influence reverberation mapping is crucial because there is growing evidence that the standard Shakura & Sunyaev (1973) thin disk model does not accurately model an AGN disk (e.g., Antonucci 1988Antonucci , 2023Antonucci et al 1989). For example, radiation MHD simulations show that pressure support from magnetic fields and radiation can lead to puffed-up disks (e.g., Gaburov et al 2012;Jiang et al 2016Jiang et al , 2019Jiang & Blaes 2020;Hopkins et al 2024), while recent observations provide additional evidence for thicker disks than predicted by the standard thin disk model (Yao et al 2023;Secunda et al 2023).…”

The Revised Third Cambridge Catalogue at 60: To Jet or Not to Jet …

“…Doppler beaming in relativistic jets and associated fluxboosting effects are present in both accretion modes, affecting all wave bands from radio to gamma rays. Antonucci (2023) [8] describes the issues in depth.…”