Abstract
We use the clustering of galaxies around distant AGNs to show with ~90% confidence that fainter AGNs are longer lived. Our argument is simple: since the measured galaxy-AGN cross-correlation length r0 ~ 5 h-1 Mpc does not vary significantly over a 10 mag range in AGN optical luminosity, faint and bright AGNs must reside in dark matter halos with similar masses. The halos that host bright and faint AGNs must therefore have similar abundances, and bright AGNs are rare partly because their lifetimes are short.
Export citation and abstract BibTeX RIS
Footnotes
- *
Based, in part, on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership between the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.