CXOU J164710.2−455216

CXOU J164710.2−455216 is an anomalous X-ray pulsar 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.[1][2] The Westerlund 1 cluster is believed to have formed in a single burst of star formation,[3] 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.[4][5]

CXOU J164710.2−455216

Artist's impression of CXOU J164710.2-455216
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Ara
Right ascension	16^h 47^m 10.20^s
Declination	−45° 52′ 16.8″
Characteristics
Evolutionary stage	Neutron star
Apparent magnitude (${\displaystyle {\begin{smallmatrix}K_{s}\end{smallmatrix}}}$)	>18.5[1]
Astrometry
Distance	approx. 16000 ly (approx. 5000 pc)
Details
Rotation	10.6105(1)s
Other designations
CXO J164710.20−455217, CXOU J164710.2−455217
Database references
SIMBAD	data

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.[6]

References

1. A Neutron Star with a Massive Progenitor in Westerlund 1, Muno et al. (2006)
2. Westerlund 1: Neutron Star Discovered Where a Black Hole Was Expected
3. On the massive stellar population of the super star cluster Westerlund 1, Clark et al. (2005)
4. Magnetar Formation Mystery Solved, eso1415 - Science Release (14 May 2014)
5. Wood, Chris. "Very Large Telescope solves magnetar mystery" GizMag, 14 May 2014. Accessed: 18 May 2014.
6. Exciting the magnetosphere of the magnetar CXOU J164710.2−455216 in Westerlund 1, Muno et al. (2007)

• Gavriil, F. P.; Woods, P. M.; Kaspi, V. M. (2006). "Chandra Target of Opportunity Observations of CXO J164710.2−455216". The Astronomer's Telegram. 901: 1. Bibcode:2006ATel..901....1G.
• cxo-j164710.2-455216