Geach, J. E., Peacock, J. A., Myers, A. D., Hickox, R. C., Burchard, M. C. and Jones, Mackenzie L.
Abstract
We measure the average deflection of cosmic microwave background photons by quasars at =1.7. Our sample is selected from the Sloan Digital Sky Survey to cover the redshift range 0.9 = z = 2.2 with absolute i-band magnitudes of M i = -24 (K-corrected to z = 2). A stack of nearly 200,000 targets reveals an 8s detection of Planck%26#39;s estimate of the lensing convergence toward the quasars. We fit the signal with a model comprising a Navarro-Frenk-White density profile and a two-halo term accounting for correlated large-scale structure, which dominates the observed signal. The best-fitting model is described by an average halo mass {log}}10({M}{{h}}/{h}-1 {M}? )=12.6+/- 0.2 and linear bias b = 2.7 ± 0.3 at =1.7, in excellent agreement with clustering studies. We also report a hint, at a 90%25 confidence level, of a correlation between the convergence amplitude and luminosity, indicating that quasars brighter than M i ? -26 reside in halos of typical mass {M}{{h}}˜ {10}13 {h}-1 {M}? , scaling roughly as {M}{{h}}\propto {L}opt}3/4 at {M}i? -24 mag, in good agreement with physically motivated quasar demography models. Although we acknowledge that this luminosity dependence is a marginal result, the observed M h-L opt relationship could be interpreted as a reflection of the cutoff in the distribution of black hole accretion rates toward high Eddington ratios: the weak trend of M h with L opt observed at low luminosity becomes stronger for the most powerful quasars, which tend to be accreting close to the Eddington limit.
