Medium resolution near-infrared spectra of the host galaxies of nearby quasars

We present medium resolution near-infrared host galaxy spectra of low redshift quasars, PG 0844+349 (z = 0.064), PG 1226+023 (z = 0.158), and PG 1426+015 (z = 0.086). The observations were done by using the Infrared Camera and Spectrograph (IRCS) at the Subaru 8.2 m telescope. The full width at half maximum of the point spread function was about 0.3 arcsec by operations of an adaptive optics system, which can effectively resolve the quasar spectra from the host galaxy spectra. We spent up to several hours per target and developed data reduction methods to reduce the systematic noises of the telluric emissions and absorptions. From the obtained spectra, we identified absorption features of Mg I (1.503 μm), Si I (1.589 μm) and CO (6-3) (1.619 μm), and measured the velocity dispersions of PG 0844+349 to be 132 ± 110 km s ^-1 and PG 1426+015 to be 264 ± 215 km s ^-1 . By using an ^MBH -σ relation of elliptical galaxies, we derived the black hole (BH) mass of PG 0844+349, log(M _BH M _⊙ )=7. 7±5.5 and PG 1426+015,log(M _BH M _⊙ )=9.0±7. 5. These values are consistent with the BH mass values from broad emission lines with an assumption of a virial factor of 5.5.