4.3.4 MRCB0346-279, z = 0.989 The quasar has large values of B_gq_ and
N_0.5_ (1957 +/- 1207 and 16.0 +/- 3.3), and there are a large number of
faint objects (23.0 < R < 24.0) to its west. However, no overdensity is
seen in Fig. 4. On closer inspection, the colours of the objects that
contribute to the large values of Bgq and N05 are too blue to be
ellipticals at z = 0.989. Fig. 9 shows the surface density of galaxies
in different colour slices. Redshift 1 ellipticals are expected to have
1.5 < R - z <2.0. The overdensity in the field of MRC B0346-279 is
caused by objects with 0.0 < R - z < 1.0, about 1 mag bluer. Therefore,
this is more likely a lower-z overdensity.
Only 10 objects are detected in the NIR, of which three
have R - K' >5. The completeness limit of the NIR data is K' = 19.0,
giving most objects m upper limit of R - K' ~4-5. For a z = 0.989 cluster
of galaxies we should expect to see objects with 18 < K' < 19 and R - K'
> 5. The median colours for objects with 18 < K' < 19 in this field are
R - K' ~3 and J - K' ~1 (Fig. 10). These colours indicate relatively
low-redshift galaxies (Fig. 1).
If the objects around MRC B0346-279 were to comprise a cluster,
it would be highly unusual as the system has no discernible red galaxy
population. This would be unique, even among the few high redshift
clusters known to date. Deep multi-object spectroscopy of this field
will be required to resolve these issues. At present, we classify MRC
B0346-279 as residing in an environment indistinguishable from the field
with a concentration of objects in the foreground.
The original and erroneous identification Bolton & Ekers
(1966AuJPh..19..275B) was with a galaxy whose redshift is 0.1756
(Browne & Savage, 1977MNRAS.179p..65B); Bolton & Ekers
(1966AuJPh..19..275B) claim the right identification and give the
redshift as 0.355 on the basis of one line in a spectrum taken by
D. Jauncey et al. (1983 - unpublished). White et al.
(1988ApJ...327..561W) sort all this out and give the corrected
redshift as 0.991.
MRC B0346-279. - ESO/3.6 m spectrum, observed by Wall & Shaver (1993,
(iii) PKS 0349-278: the VLA image in Fig. A1 is confused with a compact source
some 2.5 arcmin from the PKSCAT90 position and a marginal detection at the
PKSCAT90 position. We made an independent check of the radio centroid position
for this source by measuring it on the 4.85-GHz survey images made with the
NRAO 140-foot telescope (Condon, Broderick & Seielstad 1991). A Gaussian fit
gave a position of 03:49:31.5 -27:53:41 (B1950), consistent with the original
position (and coincident with an optical galaxy) but not with the stronger VLA
source at 03:49:41.17 -27:52:07.0 (B1950). Furthermore, the fit is clearly
extended (source sine 280 by 109 arcsec^2^ with position angle 50^deg^ after
the beam has been deconvolved). The 4.85-GHz flux of PKS 0349-278 is just over
2 Jy, but the strong source in the VLA image is only 0.3 Jy. The VLA has
resolved out most of the flux, leaving only two components plus some residuals
visible in the contour plot. The strong VLA component is probably only a
hotspot in the north-eastern lobe of the radio source. We adopt the fainter VLA
position (03:49:31.81 -27:53:31.5, B1950) which is consistent with the