Table 3.
Samples of ULXs, HLXs and galaxies under study.
| CSC2 | 4XMM | 2SXPS | Total (unique) | |
|---|---|---|---|---|
| ULX | 1234 | 667 | 304 | 2205 (1901) |
| cULX | 925 | 470 | 266 | 1661 (1448) |
| HLX | 75 | 115 | 13 | 203 (191) |
| cHLX | 63 | 92 | 13 | 168 (158) |
| Galaxies | 741 | 599 | 207 | 1547 (1303) |
| Spiral | 377 | 320 | 171 | 868 (713) |
| Elliptical | 206 | 112 | 19 | 337 (325) |
Notes. Number counts of ULXs, complete ULXs (i.e., with LX > Llim, Sect. 2.8), HLXs, complete HLXs and number of galaxies that host them (all types, spiral and elliptical), for CSC2, 4XMM-DR11, 2SXPS and their sum (in parenthesis: minus duplicates). In the compilation of unique sources, for X-ray sources observed with several instruments, the entry of smallest position error is kept. By construction of the HLX sample, the sources all have S/N > 3 and thus a higher fraction of them are complete.
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