Published in "Physics of Active Galactic Nuclei at all Scales", eds. Danielle Alloin, Rachel Johnson and Paulina Lira. Lecture Notes in Physics, Vol. 693, p.77, 2006.

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THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI

B.M. Peterson


Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA


Abstract: We review the basic observed and inferred properties of the broad emission-line region in AGNs, as well as the basics of the reverberation-mapping technique that can be used to determine the size and structure of the region. We argue that the current best evidence points to a multi-component line-emitting region, with a disk-like structure, possibly an extension of the accretion disk itself, and a disk wind being strong candidates for the origin of the broad-line emission.


Table of Contents

INTRODUCTION

BASIC INFERENCES ABOUT THE LINE-EMITTING GAS

BROAD EMISSION-LINE VARIABILITY AND THEORY OF REVERBERATION MAPPING
Basic Assumptions
Isodelay Surfaces
Velocity-Delay Maps

REVERBERATION RESULTS
Size of the BLR and Scaling with Luminosity
Reverberation and AGN Black Hole Masses

WHAT IS THE BLR?
"Cloud" Models
"Bloated Stars" Model
Double-Peaked Emission Lines
Disk Winds

WHAT WILL IT TAKE TO MAP THE BROAD-LINE REGION?

SOME OBVIOUS QUESTIONS TO KEEP IN MIND

SUMMARY

REFERENCES

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