2006/02/18 by Misty C. Bentz, Bradley M. Peterson, Richard W. Pogge +2 · 10 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy and Astrophysical Research #Background radiation #Galaxies: Formation, Evolution, Phenomena #Luminosity #Radio Astronomy Observations and Technology #Starlight #Stars #Ultraviolet astronomy #astro-ph
paper · pdf · doi:10.1086/503537
published as Astrophys.J. 644 (2006) 133-142 · 27 pages, 5 tables, 4 figures, accepted to ApJ; full resolution figures available at http://www.astronomy.ohio-state.edu/~bentz/astroph0602412.html
arxiv created 2006/02/18 · openalex publication_date 2006/06/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have obtained high-resolution images of the central regions of 14 reverberation-mapped active galactic nuclei (AGNs) using the Hubble Space Telescope Advanced Camera for Surveys High Resolution Camera to account for host-galaxy starlight contamination of measured AGN luminosities. We measure the host-galaxy starlight contribution to the continuum luminosity at 5100 Å through the typical ground-based slit position and geometry used in the reverberation-mapping campaigns. We find that removing the starlight contribution results in a significant correction to the luminosity of each AGN both for lower luminosity sources, as expected, but also for the higher luminosity sources such as the PG quasars. After accounting for the host galaxy starlight, we revisit the well-known broad-line region radius-luminosity relationship for nearby AGNs. We find the power-law slope of the relationship for the Hβ line to be 0.518 ± 0.039, shallower than what was previously reported and consistent with the slope of 0.5 expected from the naive theoretical assumption that all AGNs have, on average, the same ionizing spectrum and the same ionization parameter and gas density in the Hβ line-emitting region.