Reverberation results of a flat spectrum radio quasar PKS 1510-089 are presented from 8.5-years long spectroscopic monitoring carried out in 9 observing seasons between December 2008 to June 2017 at Steward Observatory .
Optical spectra show strong H \beta , H \gamma , and Fe II emission lines overlaying on a blue continuum .
All the continuum and emission line light curves show significant variability with a fractional root-mean-square variation of 37.30 \pm 0.06 % ( f _ { 5100 } ) , 11.88 \pm 0.29 % ( H \beta ) and 9.61 \pm 0.71 % ( H \gamma ) , however , along with thermal radiation from accretion disk non-thermal emission from jet also contribute to f _ { 5100 } .
Several methods of time series analysis ( ICCF , DCF , von Neumann , Bartels , javelin , \chi ^ { 2 } ) are used to measure lag between continuum and line light curves .
The observed frame BLR size is found to be 61.1 ^ { +4.0 } _ { -3.2 } ( 64.7 ^ { +27.1 } _ { -10.6 } ) light-days for H \beta ( H \gamma ) .
Using \sigma _ { \mathrm { line } } of 1262 \pm 247 km s ^ { -1 } measured from the rms spectrum , the black hole mass of PKS 1510-089 is estimated to be 5.71 ^ { +0.62 } _ { -0.58 } \times 10 ^ { 7 } M _ { \odot } .