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Table 3

Selection statistics.

Selection QSOs Stars Galaxies All
All 268 230 389 317 1 090 500 70 920 904
     Relative frequency in full sample 0.3782% 0.5489% 1.538%
     Relative frequency in spec sample 15.34% 22.27% 62.38%

Colour and variability QSO candidate 31 404 32 191 70 503
     Completeness 12.53% 0.011% 0.018% 0.1237%
     Purity 99.3% 0.10% 0.60%

Colour and variability star candidate 15 21 129 194 2 995 546
     Completeness 0.006% 7.24% 0.018% 5.256%
     Purity 0.07% 99% 0.91%

Colour and variability galaxy candidate 28 25 28 076 107 227
     Completeness 0.011% 0.009% 2.62% 0.1881%
     Purity 0.10% 0.09% 99.8%

Variability QSO candidate 75 690 12 704 39 284 3 390 617
     Completeness 28.2% 3.26% 3.60% 4.781%
     Purity 59.3% 9.95% 30.8%

Variability star candidate 14 005 207 701 216 312 22 854 151
     Completeness 5.22% 53.4% 19.84% 32.225%
     Purity 3.20% 47.4% 49.4%

Variability galaxy candidate 12 470 44 170 228 634 9 140 797
     Completeness 4.65% 11.35% 20.97% 12.889%
     Purity 4.37% 15.48% 80.1%

Colour QSO candidate 96 050 237 1 045 277 394
     Completeness 38.3% 0.081% 0.098% 0.4867%
     Purity 98.7% 0.24% 1.07%

Colour star candidate 17 23 111 319 3 495 123
     Completeness 0.007% 7.92% 0.030% 6.133%
     Purity 0.07% 98.6% 1.36%

Colour galaxy candidate 152 73 73 112 322 126
     Completeness 0.061% 0.025% 6.82% 5.65%
     Purity 0.21% 0.10% 99.7%

Schmidt region 85 012 24 576 79 279 5 484 750
     Completeness 31.7% 6.31% 7.27% 7.734%
     Purity 45.0% 13.01% 42.0%

Notes. Sample statistics of selections in variability and colour, including counts, completeness, and purity (see Eq. (8)). In row 1 (All), we compare spectroscopically classified objects to the full fitted source count and to the full set with spectroscopic classes to get relative frequencies in each set. In rows 5–7 and 11, for computing purity and completeness, selection counts are compared to the total spectroscopic counts. In rows 2–4 and 8–10, comparisons also require matches in WISE and PS1, because colours are used.

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