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Table 1.
Statistics of the ICRFs.
| Noise floor | Axis stability | All sources | Defining sources | |||||
|---|---|---|---|---|---|---|---|---|
| μas | μas | All | South | North | All | South | North | |
| ICRF1 | 250 | 20 | 608 | 266 | 342 | 212 | 58 | 154 |
| ICRF2 | 40 | 10 | 3414 | 1383 | 2031 | 295 | 133 | 162 |
| ICRF3 S/X | 30 | – | 4536 | 1921 | 2625 | 303 | 154 | 149 |
| ICRF3 K | – | – | 824 | 373 | 451 | 193 | 99 | 94 |
| ICRF3 X/Ka | – | – | 678 | 361 | 317 | 176 | 89 | 87 |
Notes. A dash (“–”) means that the corresponding value is not given or documented yet. The last 6 columns give the number of sources in each group for all sources and defining sources only.
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