6.5 The Available HydraI Spectroscopy

Variance-weighted mean values for $cz_{\rm hel}$, ${\log\sigma}$, Mgb, ${ {\rm Mg}_2}$, and ${ <{\rm Fe}>}$ were calculated from the DFOSC data and the data from JFK95b and J97^6.5. Where no ${ {\rm Mg}_2}$ data existed, a fiducial value was calculated from Mgb, cf. the last section. For 3 additional galaxies not observed by DFOSC and JFK95b, $cz_{\rm hel}$ and ${\log\sigma}$ were taken from LC88, with ${\log\sigma}$ offset by -0.020 to match the system of JFK95b, cf. JFK95b. The data (except for Mgb) are presented in Table .

To sum up, ${\log\sigma}$, ${ {\rm Mg}_2}$, and ${ <{\rm Fe}>}$ refer to an aperture of metric diameter 1.19 h^-1 kpc. ${\log\sigma}$ is on the system defined by JFK95b. ${ {\rm Mg}_2}$ and ${ <{\rm Fe}>}$ have been corrected for the effect of the velocity dispersion, and are on the Lick/IDS system.