An Observational Overview of Active Galactic Nuclei - Lect 04: The Broad Line Region

These lectures from 2024 give an in-depth observational overview of Active Galactic Nuclei (AGNs). They supersede my earlier ones from 2014-2015 and have many relevant updates.
This specific lecture covers the AGN Broad Line Region (BLR) where most of the strong, broad line emission in the optical/UV originates. Topics covered include AGN emission-line basics, basic BLR properties, results from BLR reverberation mapping, and the nature of the BLR.
The RUclips Playlist for these lectures is • An Observational Overv...
The RUclips links for all the lectures are the following:
* Lecture 01 (Introduction and AGN Basics) - • An Observational Overv...
* Lecture 02 (Finding AGNs and Terminology) - • An Observational Overv...
* Lecture 03 (Powers of 10 and Black-Hole Region) - • An Observational Overv...
* Lecture 04 (The Broad Line Region) - • An Observational Overv...
* Lecture 05 (Outflowing Winds) - • An Observational Overv...
* Lecture 06 (The Narrow Line Region) - • An Observational Overv...
* Lecture 07 (The Unified Model and the Torus) - • An Observational Overv...
* Lecture 08 (Jets and Radio-Loud AGNs) - • An Observational Overv...
* Lecture 09 (Feeding the Monster) - • An Observational Overv...
* Lecture 10 (AGN Evolution) - • An Observational Overv...
The PDF slides are available on Zenodo at zenodo.org/records/11180044
Even with these lectures, I can only scratch the surface of this truly massive field. I aim to give some of the main ideas, without noting every special case or technical exception. My apologies in advance if your favorite topic is not covered in as much depth as you would like. Most references are just examples from the vast AGN literature and have an implicit "e.g." before them throughout. See Lecture 1 for further comments on these points as well as some useful textbooks where you can learn more.
Thoughtful, constructive, and broad-minded feedback is welcomed by email - fairly considering the enormous scope and practical challenges of preparing such lectures.
These lectures were prepared as part of a seminar course at Penn State (Astro 589), and support from Penn State is gratefully acknowledged. Any findings, opinions, conclusions, or recommendations expressed in this material are those of the author and do not necessarily reflect the views of Penn State.