An "Anomalus X-ray Pulsar" (AXPs) is a type of magnetar - a young, isolated, highly magnetized neutron star. These energetic X-ray pulsars are characterized by their slow rotation periods (~2-12 seconds), and large magnetic fields of around ~1013-1015 gauss (1 to 100 gigateslas). There are, as of 2017, 12 confirmed and 2 candidate AXPs. The identification of AXPs with magnetars was motivated by their similarity to another enigmatic class of sources, the soft gamma repeaters.
Current list of list of AXP candidates as of 2003:
| Name | Rotation period (seconds) |
|---|---|
| AXP 1E 2259+586 | 6.98 |
| AXP 1E 1048-59 | 6.45 |
| AXP 4U 0142+61 | 8.69 |
| AXP 1RXS 1708-40 | 11.0 |
| AXP 1E 1841-045 | 11.8 |
| AXP AXJ1844-0258 | 6.97 |
| AXP CXJ0110-7211 | 5.44 |