We present low-resolution absorption-line spectra of three candidate close ( < 3 \arcsec ) companions to the low redshift QSOs 3CR 323.1 , PG 1700+518 and PKS 2135 - 147 .
The spectra were obtained with LRIS on the Keck telescopes and with the Faint Object Spectrograph on the University of Hawaii 2.2 m telescope .
For 3CR 323.1 and PG 1700+518 , we measure relative velocities that are consistent with an association between the QSOs and their companion galaxies .
The spectral features of the companion galaxy to 3CR 323.1 indicate a stellar population of intermediate age ( \sim 2.3 Gyr ) .
In contrast , the spectrum of the companion object to PG 1700+518 shows strong Balmer absorption lines from a relatively young stellar population , along with the \ion Mg1 b absorption feature and the 4000 Å break from an older population .
By modeling the two stellar components of this spectrum , it is possible to estimate the time that has elapsed since the end of the most recent major starburst event : we obtain \sim 0.1 Gyr .
This event may have coincided with an interaction that triggered the QSO activity .
Finally , our spectroscopy shows conclusively that the supposed companion to PKS 2135 - 147 is actually a projected Galactic G star .