Disc heating in NGC 2985

Various processes have been proposed to explain how galaxy discs acquire th eir thickness. A simple diagnostic for ascertaining this 'heating' mechanis m is provided by the ratio of the vertical to radial velocity dispersion co mponents. In a previous paper we have developed a technique for measuring t his ratio, and demonstrated its viability on the Sb system NGC 488. Here we present follow-up observations of the morphologically similar Sab galaxy N GC 2985, still only the second galaxy for which this ratio has been determi ned outside the solar neighbourhood, The result is consistent with simple d isc-hearing models that predict ratios of sigma(z)/sigma(R) less than one.