Astron. Astrophys. 345, 363-368 (1999)
In this paper 19 additional cluster candidates detected in EIS
patch B have been presented. Cluster candidates have also been
identified using the V-band galaxy catalogs available for
patches A and B. The analysis of the cross-identification of the
V- and I-band detections, as summarized in Table 3,
leads to the following general conclusions:
About 95% of the cluster candidates with
and about 30% with
, primarily rich clusters, are
confirmed using the V-band data. This result provides
confidence about the reality of the cluster candidates detected in the
areas where only I-band data are available.
About 80% of the low redshift ()
candidates show a suggestion of the CM relation expected for
early-type galaxies in clusters. This detection serves as an
independent confirmation of the candidate clusters. It also provides
an independent redshift estimate, which is in general consistent with
the estimates from the matched filter method.
The well-defined CM relations provide the possibility of selecting
individual galaxies for follow-up spectroscopy to measure more
accurate redshifts and velocity dispersions.
Unfortunately, the band data are
not deep enough to use the CM relation to gain leverage for candidates
at . For future surveys using
wide-field cameras, such as the Pilot Survey (Renzini 1998) to be
conducted at the ESO 2.2m telescope, the option of doing significantly
deeper band observations should
therefore be considered.
Table 3. Summary of the cross-identification rates.
© European Southern Observatory (ESO) 1999
Online publication: April 19, 1999