We present host stellar velocity dispersion measurements for a sample of 88 broad-line quasars at 0.1 < z < 1 ( 46 at z > 0.6 ) from the Sloan Digital Sky Survey Reverberation Mapping ( SDSS-RM ) project .
High signal-to-noise ratio coadded spectra ( average { S / N } \approx 30 per 69 { km s ^ { -1 } } pixel ) from SDSS-RM allowed decomposition of the host and quasar spectra , and measurements of the host stellar velocity dispersions and black hole ( BH ) masses using the single-epoch ( SE ) virial method .
The large sample size and dynamic range in luminosity ( L _ { 5100 } = 10 ^ { 43.2 - 44.7 } { erg s ^ { -1 } } ) lead to the first clear detection of a correlation between SE virial BH mass and host stellar velocity dispersion far beyond the local universe .
However , the observed correlation is significantly flatter than the local relation , suggesting that there are selection biases in high- z luminosity-threshold quasar samples for such studies .
Our uniform sample and analysis enable an investigation of the redshift evolution of the M _ { \bullet } - \sigma _ { * } relation relatively free of caveats by comparing different samples/analyses at disjoint redshifts .
We do not observe evolution of the M _ { \bullet } - \sigma _ { * } relation in our sample up to z \sim 1 , but there is an indication that the relation flattens towards higher redshifts .
Coupled with the increasing threshold luminosity with redshift in our sample , this again suggests certain selection biases are at work , and simple simulations demonstrate that a constant M _ { \bullet } - \sigma _ { * } relation is favored to z \sim 1 .
Our results highlight the scientific potential of deep coadded spectroscopy from quasar monitoring programs , and offer a new path to probe the co-evolution of BHs and galaxies at earlier times .