Abstract
Abstract
Weak emission-line quasars (WLQs) are a subset of type 1 quasars that exhibit extremely weak Lyα + N v
λ1240 and/or C iv
λ1549 emission lines. We investigate the relationship between emission-line properties and accretion rate for a sample of 230 “ordinary” type 1 quasars and 18 WLQs at z < 0.5 and 1.5 < z < 3.5 that have rest-frame ultraviolet and optical spectral measurements. We apply a correction to the Hβ-based black hole mass (M
BH) estimates of these quasars using the strength of the optical Fe ii emission. We confirm previous findings that WLQs’ M
BH values are overestimated by up to an order of magnitude using the traditional broad-emission-line region size–luminosity relation. With this M
BH correction, we find a significant correlation between Hβ-based Eddington luminosity ratios and a combination of the rest-frame C iv equivalent width and C iv blueshift with respect to the systemic redshift. This correlation holds for both ordinary quasars and WLQs, which suggests that the two-dimensional C iv parameter space can serve as an indicator of accretion rate in all type 1 quasars across a wide range of spectral properties.
Funder
National Science Foundation
National Aeronautics and Space Administration
MOST ∣ National Natural Science Foundation of China
EC ∣ ERC ∣ HORIZON EUROPE European Research Council
Israel Science Foundation
Publisher
American Astronomical Society
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
2 articles.
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