We present measurements of the cross-correlation of the triply-ionized carbon ( CIV ) forest with quasars using Sloan Digital Sky Survey Data Release 14 .
The study exploits a large sample of new quasars from the first two years of observations by the Extended Baryon Oscillation Spectroscopic Survey ( eBOSS ) .
The CIV forest is a weaker tracer of large-scale structure than the Ly \alpha forest , but benefits from being accessible at redshifts z < 2 where the quasar number density from eBOSS is high .
Our data sample consists of 287,651 CIV forest quasars in the redshift range 1.4 < z < 3.5 and 387,315 tracer quasars with 1.2 < z < 3.5 .
We measure large-scale correlations from CIV absorption occuring in three distinct quasar rest-frame wavelength bands of the spectra referred to as the CIV forest , the SiIV forest and the Ly \alpha forest .
From the combined fit to the quasar-CIV cross-correlations for the CIV forest and the SiIV forest , the CIV redshift-space distortion parameter is \beta _ { CIV } = 0.27 _ { -0.14 -0.26 } ^ { +0.16 +0.34 } and its combination with the CIV linear transmission bias parameter is b _ { CIV } ( 1 + \beta _ { CIV } ) = -0.0183 _ { -0.0014 -0.0029 } ^ { +0.0013 +0.0025 } ( 1 \sigma and 2 \sigma statistical errors ) at the mean redshift z = 2.00 .
Splitting the sample at z = 2.2 to constrain the bias evolution with redshift yields the power-law exponent \gamma = 0.60 \pm 0.63 , indicating a significantly weaker redshift-evolution than for the Ly \alpha forest linear transmission bias .
Additionally , we demonstrate that CIV absorption has the potential to be used as a probe of baryon acoustic oscillations ( BAO ) .
While the current data set is insufficient for a detection of the BAO peak feature , the final quasar samples for redshifts 1.4 < z < 2.2 from eBOSS and the Dark Energy Spectroscopic Instrument ( DESI ) are expected to provide measurements of the isotropic BAO scale to \sim 7 \% and \sim 3 \% precision , respectively , at z \simeq 1.6 .