Anomalous X-ray pulsars (AXPs) are an observational manifestation of magnetars—young, isolated, highly magnetized neutron stars. These energetic X-ray pulsars are characterized by slow rotation periods of ~2–12 seconds and large magnetic fields of ~1013–1015gauss (1 to 100 gigateslas). As of 2017[update], there were 12 confirmed and 2 candidate AXPs known.[1] The identification of AXPs with magnetars was motivated by their similarity to soft gamma repeaters.
The AXP candidates and their estimated rotation period in seconds, as of 2003[update], were:
The second, fourth, and last names have been abbreviated.
References
^SGR/AXP Online Catalog (An online catalog of SGR/AXP properties maintained by the pulsar group at McGill University)
Sources
Van Paradijs, J.; Taam, R. E.; Van Den Heuvel, E. P. J. (1995). "On the nature of the 'anomalous' 6-s X-ray pulsars". Astronomy and Astrophysics. 299: L41. Bibcode:1995A&A...299L..41V.
Duncan, Robert C.; Thompson, Christopher (1996). "Magnetars". AIP Conference Proceedings. Vol. 366. p. 111. doi:10.1063/1.50235.