The 
MEFOS fields span a diameter of 
at the
Shapley supercluster redshift. Therefore, we expected to observe galaxies
belonging both to the targeted Abell clusters and to the supercluster,
besides some background/foreground galaxies in each MEFOS field. This is
borne by the velocities reported in Table 2. Velocity membership in the
clusters studied in the present work show large differences from one
cluster to another. Figure 1 (click here) shows the velocity histograms of the
15 clusters studied in the present paper.
Figure 1: Velocity histograms of 15 clusters from the present paper
Many galaxies are background and, in some fields, it is unclear whether an
Abell cluster is present at all. In Table 3 (click here) we summarize the
derived kinematical parameters for the clusters or clumps that can be
identified in the area. Figure 2 (click here) plots cone diagrams of the
observed galaxies, plus all galaxies with known redshifts in the
supercluster. Figure 3 (click here) shows the radial velocity histogram for the
1385 galaxies having data available in the literature and from the present
work, with 
in the central region of the supercluster.
There are two clear peaks in the distribution, one around 
with
(208 objects), corresponding to galaxies in the general
Hydra-Centaurus region, and the main peak centered at 
with
(620 galaxies), which corresponds to the Shapley
supercluster. Note that the first peak can be related with the nearby
cluster A3627 (
) associated
with the Great Attractor" (Kraan-Korteweg et al. 1996). There
may be a third peak near 
possibly connected to the supercluster
as shown on the wedge diagram displayed in Fig. 3 (click here). The two
dimensional distribution of galaxies in the central region of the Shapley
supercluster using different symbols for different velocity ranges (as
indicated in the figure caption) is shown in Fig. 4 (click here).
Figure 2: Wedge diagram in right ascension (left) and declination (right) of
galaxies with 
in the central region of the Shapley
supercluster. Data from the literature and from the present paper are
displayed
Figure 3: Radial velocity histrogram for all the galaxies with 
in the central region of the Shapley Supercluster
Notes on individual clusters:
We have inspected by eye the observed galaxies and surrounding fields on the film copies of the J and R SRC/ESO surveys to evaluate the relationship between the supercluster members. Integrating comments from the previous literature, we can make the following comments:
A3524:
Background cluster with Bautz-Morgan type I. The central cD galaxy was not
observed, but the 14 closest observed galaxies, with velocities in the range
, are consistent with being members of a cluster. This
supersedes the value z=0.054 given by Quintana et al. (1995)
taken from the NED database. Only 2 galaxies are members of the Shapley
Concentration (S.C) and 4 are background at larger distances.
A3531:
Only one galaxy appears to be member of the S.C. Except 2 foreground
galaxies, all the other objects are in a very large range of background
velocities; the reality of the cluster itself is questionable. The average
redshift quoted in Table 3 (click here) is derived from the five galaxies in the
range 
.
A3542:
The field in the direction of A3542 is complex. Postman & Lauer
(1995) identify galaxy No. 29 as the brightest cluster galaxy (BCG),
with a velocity of 
, in agreement with our measurement and with
Vettolani et al. (1990). However, no other measured galaxy in
the field has a similar redshift, making the BCG a likely spurious
identification. Vettolani et al. (1990) suggested the reality
of this cluster as a member of the S.C on the basis of 2 measured galaxies
(as given in Table 3), with a redshift 0.051. We measured two other
galaxies in that same redshift range, i.e. Nos. 15 and 18. We also observed
8 galaxies in the range 
, range in which Vettolani et al.\
(1990) also observed two galaxies between 
.
Furthermore, we obtained 4 galaxies in the range 
and
7 more in the far background. We can only conclude to the presence of a
superposition of at least 4 sheets of galaxies: at the S.C. redshift, at
20000 
and two groups in the ranges 
(10 objects)
and 
(7 objects), the later with dispersion velocities
respectively 
and 
.
A3545 and A3549:
These two areas contain only one galaxy member of the S.C. A possible
cluster with 13 objects is defined in the range 
with a
mean value 
and a dispersion velocity about
. Two sets of background galaxies are also located around 28000
and 
.
Figure 4: The two dimensional distribution of galaxies in the central
region of the Shapley supercluster. Four different velocity cuts have been
represented by different symbols. Plusses: 
a); Open
squares: 
b); Open triangles:
c), and
Crosses: 
d). The X
and Y scale are given in arcsec
from the center of the figure with R.A: 13h 15mn and Dec:
A3554:
This cluster clearly belongs to the S.C. 15 galaxies have been observed
in the range 
with a mean value
and a dispersion velocity about 
.
A3557:
6 galaxies have velocities consistent with the S.C. A background structure
with 8 objects appears in the range 
with a mean value
and a dispersion velocity about 
,
similarly to A3545 and A3549. 5 galaxies are in the range
.
A3566:
This cluster belongs to the S.C. 18 galaxies (14 from the present work and
4 in Vettolani et al. 1990) are in the range 
with a mean velocity 
and a dispersion velocity of
.
A3575, A3577 and A3578:
These three clusters have a common foreground structure defined by
26 galaxies at a mean velocity of 11199 with a dispersion about only
. The S.C. reaches these positions as 20 galaxies are members of
the S.C. with a mean value 
with
while only 20 galaxies are background ones. Note that
for A3578 Vettolani et al. (1990) obtained two similar sets of
velocities only based upon 5 velocities. This foreground structure has a
similar redshift to A3571 at z=0.040 (Quintana & de Souza
1993). Further data can clarify the question of the conecction of
this structure to the S.C.
A3581:
This cluster is really a foreground one with 13 significant members and five
from the litterature (see Vettolani et al. 1990), in the range
with 
and a dispersion velocity
about 
.
AS718, AS731 and AS733:
8 galaxies from AS718 belong to the S.C (
,
dispersion 
), and 3 objects are foreground ones. 7 galaxies from
AS731 are members of the S.C (
, dispersion
), while a background group with 7 galaxies appears around
in AS733.