CXOU J164710.2−455216
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Ara |
| Right ascension | 16h 47m 10.20s |
| Declination | −45° 52′ 16.8″ |
| Characteristics | |
| Evolutionary stage | Neutron star |
| Apparent magnitude () | >18.5 |
| Astrometry | |
| Distance | approx. 16,000 ly (approx. 5,000 pc) |
| Details | |
| Rotation | 10.6105(1)s |
| Other designations | |
| CXO J164710.20−455217, CXOU J164710.2−455217 | |
| Database references | |
| SIMBAD | data |
CXOU J164710.2−455216 is an anomalous X-ray pulsar and magnetar in the massive galactic open cluster Westerlund 1. It is the brightest X-ray source in the cluster, and was discovered in 2005 in observations made by the Chandra X-ray Observatory. The Westerlund 1 cluster is believed to have formed in a single burst of star formation, implying that the progenitor star must have had a mass in excess of 40 solar masses. The fact that a neutron star was formed instead of a black hole implies that more than 95% of the star's original mass must have been lost before or during the supernova that produced the magnetar.
On 21 September 2006 the Swift satellite detected a 20ms soft gamma-ray burst in Westerlund 1. Fortuitously, XMM-Newton observations had been made four days earlier, and repeat observations 1.5 days after the burst revealed the magnetar to be the source of the burst, with the X-ray luminosity increasing by a factor of 100 during the outburst.