Column description of tables 2.4 (-28d<DEC<-15d) and table 3.4 (-15d<DEC<-08d)
C 1/2: Abell cluster name; within each cluster the order is that of increasing RA, except where the possibility of a physical association exists between nearby sources, in which case they appear as consecutive entries with the source names appended by a + sign.
Southern sources fall into two categories: those above the limiting flux and within the area of teh map as defined in Table 2.3, and a second smaller area containing sources outside this area (to N or S) but which are included because of their detection in the original Molonglo 408MHz survey. An asterisk before the source name denotes membership of this second category.
Northern sources observed only at 408MHz (A1069, A2410, A2448, A2525) or sources which were outside the mapped regions at 843MHz and 1415MHz are indicated by an asterisk before the source name. Three sources not detected at 408MHz but reliably identified at 843MHz with one of the brightest three galaxies in clusters A117, A358 and A2670 are noted with a '#'. A fourth source, a doubtful ID in A415, is also included.
C 3/4: B1950 position. Where little or no structure is evident a simple fitted
position is given. For well resolved SOUTHER sources a code letter
immediately after the declination signifies one of the following:
P= listed position is that of the radio peak, taken from the map
M= position is that of the midpoint of a likely double source
C= source shows simple, approximately linear, extension but no well-defined peak: the position is that of the radio centroid
In addition, for NORTHERN sources (-15d<DEC<-08d) this symbols means:
a= rms error dRA=1.5"--2", dDEC ~ 5"
b= rms error dRA=1.5"--2", dDEC ~ 7"--10"
c= rms error 5" in each coordinate
d= rms error 7"--10" in each coordinate
C 5-7: S843 is the MOST flux density in mJy, and where available, S408 and S1415 denote the Molonglo and Fleurs flux densities, respectively.
Col 8: The spectral index is that between 843 and 408MHz, defined as S~nu^+alpha. In cases where the Molonglo beam failed to resolve neighbouring sources, columns 5 and 8 contain composite figures, with the spectral index appended by an asterisk. In view of the limited number of measurements available, the 1415 MHz data were not included in the spectral index estimates: instead, the presence of a '+' ['-'] after the sp. index value signifies that the 1415MHz flux lies >2 sigma above [below] the 408MHz-843MHz extrapolation. The standard errors at 408MHz are ~7% for sources with S408>= 1 Jy, rising to ~15% at the weaker end of the range with S408~90mJy. An additional standard error of ~7% is present for sources larger than 2'. An expression for the standard eror in the 1415MHz flux densities for unresolved sources is given in sect. 3.3: the value for stronger sources is ~15%. For extended sources a further 10% standard error is estimated to be present. Uncertain measurements with a likely error of >20% are noted by a colon after the figure.
Col 9: Distance from the Cluster Centre, in arcmin of the source from the nominal cluster centre of Sastry & Rood (1971).
Col 10 the same distance expressed as a fraction of the Abell radius defined as 1.71/z arcmin. The redshifts z used here are nearly all spectroscopic measurements and are taken from Table 4.4 of this Thesis.
Col 11 Radio Morphology according to the following codes:
-: unresolved (not that weaker sources may lack S/N to be resolved)
X= slightly extended, clearly broadening the MOST beam (in either coordinate) but not sufficiently to allow a useful estimate of the source extent. The extent in most cases will be <35" x 45" csc|DEC|
Xn= moderately extended, for extension >=1 beamwidth, the numeral n gives the approximate source extent to the nearest arcmin.
Dn= double; as well as clear instances of physical doubles this category includes all pairs of sources separated by <1' and with a likely opt.ID near the centroid. The numeric suffix gives the distance, in arcmin, between the two radio peaks. It is unlikely, on statistical grounds, that more than 2-3 chance "line-of-sight" doubles fall under this classification. In doubtful cases the sources are listed separately with a bracket linking the source name.
Nn= complex. For morphology more complex than that covered above, a reference is given in Col. 15 to an additional clarifying note, to be found in the Notes. Again, the numerci suffix gives the appropriate source extent in arcmin.
Col 12 Optical IDs were sought for all sources in the catalogue using computer-drawn
transparent overlays on POSS prints. The symbol in col. 12 indicates membership
of one of 5 ID categories ... [lengthy explanation follows...]
A: unresolved with 2.5 sigma of the combined radio-optical error
B: extended sources with an ID generally within the 50% radio contour
C: large physical radio-optical displacement of up to ~20 kpc (H0=100) at the cluster distance with galaxies brighter than 18mag
S: stellar objects with 2.5 times the combined radio/optical position error, including confirmed QSOs; for NORTHERN sources the opt. objects had to lie within 20" in each coordinate of the radio position.
BF: blank field
Col 13 Abbreviated description of the optical candidate, consisting of an estimated
mag followed by the object type. Red magnitudes of galaxies were estimated to
the nearest half-magnitude from enlargements of PSS E rints and are based on
the scale of Abell (1958). Estimates for stellar magnitudes were made to
the nearest magnitude only. Symbols signify:
E= elliptical galaxy; C= compact elliptical galaxy; L= lenticular galaxy; S= spiral galaxy; G= galaxy of undetermined type; * = confirmed star; RSO, BSO, NSO= red, blue or neutral stellar object; QSO= confirmed QSO, with reference indicated in Col. 15.
Col 15 Displacement, in each coordinate of the measured optical position with respect to the listed radio position, in arcsec. Optical positions were measured from PSS glass copies using an x-y measuring machine with an accuracy of better than 1" on compact objects (Hunstead 1971, 1974).