XMM-Newton reveals a candidate period for the spin of the ``Magnificent Seven'' [...]
In section 7. Stellar structure and evolution
XMM-Newton reveals a candidate period for the spin of the ''Magnificent Seven'' neutron star RX J1605.3+3249
The "Magnificent Seven" is a group of thermal X-ray emitting isolated neutron stars whose properties are closer to magnetars than classical rotationally powered pulsars. To date, rotational periods have been determined for all but RX J1605+3249. This paper reports the XMM-Newton successful detection of pulsed emission, a period of 3.38 sec, and evidence of a spindown that implies a dipole field of about 7 x 1013G. This would be the strongest field of the group, nearly overlapping the distribution of magnetars. The pulsed emission is unusually hard, mainly above 0.5 keV, while the unpulsed spectrum yields a temperature of about 0.1 keV. The authors also report detecting an absorption feature at 0.57 keV that is typical of thermal emitters, whose origin is still uncertain, and a cooler thermal continuum component at 45-60 eV.