are shown in Figure .
All literature data have been aperture corrected,
and the individual values from D87 and F94 have been averaged, cf. JFK95b.
The mean differences
are given in Table .
the following offset was adopted to reach the system of
JFK95b, which is also the system of D87 (cf. JFK95b):
Comparisons of are shown in Figure . The consistency is good. In the case of JFK95b, Fig. (c), we can compute the total error on expected from the internal uncertainties on our and their measurements. This error is 17 km/s, which is far less than the observed rms scatter of 48 km/s. Thus, other sources of error, such as the wavelength calibration, dominate. If the observed scatter in the comparison with JFK95b is divided equally on our and their data, the found external accuracy is 34 km/s. JFK95b find their external accuracy to be 35 km/s, in good agreement with this.
J97 presents various line indices calibrated to the Lick/IDS system.
Figure (a) shows the comparison for
The mean difference is zero,
and therefore the DFOSC
values are already on the Lick/IDS system,
Figure (b) shows the comparison for Mgb.
The mean difference is
used to transform the DFOSC data to the Lick/IDS system:
could not be measured from all the DFOSC spectra
since the blue pseudocontinuum of
fully included in the observed wavelength range
for galaxies redshifted less than
Therefore, Mgb was used instead for the calibration of
to the Lick/IDS system.
A transformation from Mgb to
has been established by
In Figure , real DFOSC values are compared with fiducial values calculated from Mgb using Eq. (). In panel (a) the Mgb data are from the DFOSC itself (thus being a sort of an internal comparison). The mean difference is . In panel (b) the Mgb data are from J97. The mean difference is .
The real DFOSC
values were also compared
values from the literature.
In comparison with D87, F94, and J97, mean differences
-0.029, -0.014, and -0.013 were found for
2, 1, and 2 galaxies in common, respectively.
It was concluded, that the best transformation to the Lick/IDS system was
and the following offset has been applied to the LC88 data (cf. JFK95b)
Properties of E and S0 Galaxies in the Clusters HydraI and Coma
Master's Thesis, University of Copenhagen, July 1997
Bo Milvang-Jensen (email@example.com)