The Medium Redshift Clusters CL0017-20 and CL0500-24
L. Infante, P Fouque, G. Hertling, M.J. Way, E. Giraud, H. Quintana
Abstract
We present magnitudes and redshifts of galaxies in the cluster of galaxies CL0017-20 and in the double cluster CL0500-24. Luminosity functions and velocity distributions have been derived. CL0017-20 possesses a virial mass of
2.9×
10
14
M
⊙
and a \vmag band luminosity of
2.3±0.5×
10
12
L
⊙
(
M/
L
V
=127
), much of it in a very compact core of size 113 kpc. Our new velocities and photometry of CL0500-24 confirm its double nature. Our group algorithm clearly detects two subconcentrations with masses 1.9 and
2.2×
10
14
M
⊙
. Its total \vmag band luminosity amounts to
2.7±0.8×
10
12
L
⊙
(
M/
L
V
of 157). Since the crossing and collapse times in both clusters are smaller than the age of the Universe, they appear bound and virialized. It is surprising that although
M/L
is small in these clusters, giant arcs have been detected in both.