Published online by Cambridge University Press: 01 August 2006
Our aim is to study the stellar kinematics in hosts of AGN. We do so by measuring nuclear stellar velocity dispersions (σ⋆). Our sample comprises spectra of 78 objects, 69 of which are Seyfert galaxies, in the region around the λλ8498.02, 8542.09, 8662.14 Calcium triplet (CaT). We investigate two methods to measure σ⋆: (1) the direct fitting method (DFM), which makes use of our stellar population synthesis code Starlight, and (2) the cross-correlation method (CCM), for which we use the fxcor package in IRAF. Both methods yield velocity dispersions consistent to within 19 km/s on-average. We have also measured the CaT equivalent width (WCaT) and the λ3933 CaII K equivalent width (WK) for the objects in our sample. Other studies have shown that WK is a powerful tracer of starbursts in Seyfert nuclei, so we check if WCaT can be used in the same way. We have also analysed a sub-sample of 34 spatially resolved objects with reasonably good off-nuclear signal-to-noise. We study the spatial variations of both σ⋆ and WCaT. We see no dilution in WCaT for composite starburst + Seyfert 2 galaxies, in contrast to the dilution in the WK (studied by other authors) for the same objects.