| proportional counter array | PCA | 33 | 6 | 1.000616 | 9803018,9803267,etc |
| nasa extragalactic database | NED | 15 | 4 | 2.000415 | 9803099,9803039,etc |
| rosat all sky survey | RASS | 29 | 4 | 1.000506 | 9803175,9803248,etc |
| signal to noise | S/N | 26 | 4 | 1.000671 | 9803175,9803208,etc |
| low energy concentrator spectrometer | LECS | 19 | 3 | 2.000785 | 9803129,9803015,etc |
| low surface brightness | LSB | 87 | 3 | 2.003984 | 9803308,9803031,etc |
| broad emission line region | BLR | 77 | 3 | 2.006006 | 9803044,9803183,etc |
| proportional counter unit | PCU | 6 | 3 | 1.000231 | 9803267,9803278,etc |
| full width half maximum | FWHM | 7 | 3 | 1.000117 | 9803327,9803140,etc |