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Figure 1:
The spectral index distribution for the compilation of sources from
Parkes surveys known as PKSCat90. The sub-sample selected has
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Figure 2:
The redshift distribution (histogram) for the sources of Sample 1
(Table 1). The hatched area shows the redshift distribution for beamed
objects alone, the QSOs + BL Lac objects, while the clear region represents
the galaxies. The 6 dotted lines show the appropriately-scaled distributions
predicted by the flat-spectrum (
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Figure 3:
The radio luminosity function (H0 = 70 km s-1 Mpc-1,
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Figure 4: The integral radio luminosity function for the QSOs of the Parkes 0.25-Jy flat-spectrum sample, computed in the five redshift ranges of Fig. 3: 0 - 0.5 (red), 0.5 - 1.0 (green), 1.0 - 2.0 (blue), 2.0 - 3.0 (orange) and 3.0 - 5.0 (light blue). Vertical lines again indicate limits of completeness for each redshift range, due to spectral-index spread. The upper curve is the total integrated luminosity function, complete for all powers only at the very highest luminosities. |
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Figure 5:
Space densities as a function of redshift for 5 power
ranges,
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Figure 6: The radio spectra of all sources in Sample 2, Table 2, in their rest frame. Data are at observing frequencies of 0.365, 1.4, 2.7, 5.0, 8.40 and 8.87 GHz, and flux densities are normalized by S0, the interpolated rest-frame flux density at 2.7 GHz. |
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Figure 7:
The luminosity-volume plane for the 252 QSOs with measured
redshifts, in survey areas with completeness limit
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Figure 8:
Two sources to illustrate redshift limits in the single-source
analysis. For each object, the upper panel shows the spectrum in the rest
frame, while the lower panel shows the object in the P-V plane. In each case
the individual cutoff lines are shown as the segmented black curves in the
P-V plane, while the smooth coloured curves represent completeness limits at
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Figure 9:
The predicted numbers of QSOs at high redshifts. The histograms are
the results of 2000 trials of end-to-end bootstrap testing. The left-most
histogram was compiled using high-frequency spectral data at 8.40 GHz and
8.87 GHz, with the 8.87-GHz (near-contemporary) flux densities used in
preference if both were available. The right histogram represents 2000 results
from bootstrap testing when only the 8.87-GHz flux densities were used.
The vertical line to the left indicates the observed number of QSOs at high
redshifts, as discussed in the text. These bootstrap test were carried out in
the simple geometry
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Figure 10:
Above: space density ![]() ![]() |
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Figure 11:
Left: relative space density of QSOs (![]() ![]() |
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