This paper is the second in a series reporting redshifts for galaxies found at very low galactic latitudes, obtained for the purpose of mapping large-scale structures previously hidden by the southern Milky Way. The first paper (Kraan-Korteweg et al. 1995 - hereafter Paper I) dealt with the Hydra-Antlia region; it also gave full details of the nature of the survey. The present paper covers the "Crux'' region immediately neighbouring Hydra-Antlia; it does not repeat information given in Paper I, to which the reader is referred for an extensive description of the motivation, survey and observing procedures.
Figure 1: The distribution in Galactic coordinates of the galaxies in the Crux area.
The surveyed area is indicated and the newly identified galaxies with
arcminutes entered as small dots. The larger dots in the
surrounding area display the Lauberts galaxies (
).
The Hydra, Antlia, Centaurus, Pavo and ACO 3627 (=Norma) clusters are
labelled, as is the position of the Vela overdensity (reported in Paper I)
As before, galaxies in the general galactic latitude
range have been found by scanning film copies of
the SRC IIIaJ survey under 50 times magnification, the details of which
will be presented as a catalogue (Woudt & Kraan-Korteweg 1997,
hereafter WKK97). For the present work, some 500 square degrees of sky has
been searched. It involves 21 fields limited at
,
namely
,
,
and
.
Figure 1 (click here) shows the distribution of the 3760 galaxies found in the
Crux region. Only (= 87) of these galaxies had been
catalogued before by Lauberts (1982). The entire area surveyed
so far by us is indicated in Fig. 1 (click here). The dashed line on the right
demarcates the Hydra-Antlia region, the middle section (solid line) is the
Crux region whereas the dashed line on the left shows the Great Attractor
region.
The newly found galaxies in the Crux region significantly reduce
the width of the "Zone of Avoidance'' (ZOA) created by the Milky Way.
Nevertheless there is a generally sharp cutoff along the northern
boundary at and a more gradual but irregular extinction
between
and
on the southern edge.
The forthcoming blind HI-survey with the multi-beam system at Parkes should
unveil the remaining parts of the extragalactic sky between these boundaries.
The distribution of optically detected galaxies inside the Crux region is far
from smooth. North of the Milky Way, there are three apparent concentrations
at galactic longitudes and
. The latter
two suggest a continuation of the Centaurus Wall into the ZOA. South of the
Milky Way, there is a concentration (at
) which is most
likely a distant overdensity as the survey reveals a corresponding excess
of smaller fainter galaxies.
The Crux region does include part of the "Great Attractor'' (GA)
(Lynden-Bell et al. 1987). However, the main component of the
GA lies within the boundaries of our neighbouring search area () including the centre of the GA which
Kolatt et al. (1995) predict at
,
.
That region will be covered in a third paper in this series; it is dominated
by ACO 3627 - hereafter named the Norma cluster - already recognised
as a nearby massive cluster (Kraan-Korteweg et al. 1996 -
hereafter KK96) while work on this survey was in progress.