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Table 2

Average number of UDGs per group in bins of halo mass.

Binmean N groups UDGs per group Richness
log10 [M200/M]

12.23 8
12.62 38
13.03 139
13.36 107
13.77 27
14.04 3
14.52 1

Notes. Bins have a width of 0.4 dex in halo mass, starting at 1012 M. These are the data points shown in Fig. 3. Two types of uncertainty are given: first the Poisson uncertainty on the average value in each bin, second the bootstrap uncertainty from resampling groups in each bin (drawing with replacement). The latter uncertainty also includes the Poisson uncertainty on individual groups, and is therefore never smaller than the former (and they are equal when there is only one group in a bin). The last column lists as a comparison the richness of bright galaxies in the same groups and bins.

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