Found this in this morning's NatureAlert.
Al.
Editor's Summary
24 August 2006
Magnetars are radio stars
Anomalous X-ray pulsars (AXPs) are slowly rotating neutron stars with very bright and variable X-ray emission. They are believed to be magnetars — powered by strong magnetic fields — but unlike 'normal' pulsars, never seem to have pulsed radio emissions. Camilo
et al. report that the anomalous X-ray pulsar XTE J1810-197 does in fact emit radio pulses at every rotation. This means that magnetars can be radio pulsars, and there is no need for alternative models to explain accretion without radio pulse production.
Letter
Nature 442, 892-895(24 August 2006) | doi:10.1038/nature04986; Received 12 May 2006; Accepted 14 June 2006
Transient pulsed radio emission from a magnetar
Fernando Camilo
1, Scott M. Ransom
2, Jules P. Halpern
1, John Reynolds
3, David J. Helfand
1, Neil Zimmerman
1 and John Sarkissian
3
Anomalous X-ray pulsars (AXPs) are slowly rotating neutron stars with very bright and highly variable X-ray emission that are believed to be powered by ultra-strong magnetic fields of >1014 G, according to the 'magnetar' model1. The radio pulsations that have been observed from more than 1,700 neutron stars with weaker magnetic fields have never been detected from any of the dozen known magnetars. The X-ray pulsar XTE J1810 - 197 was revealed (in 2003) as the first AXP with transient emission when its luminosity increased 100-fold from the quiescent level2; a coincident radio source of unknown origin was detected one year later3. Here we show that XTE J1810 - 197 emits bright, narrow, highly linearly polarized radio pulses, observed at every rotation, thereby establishing that magnetars can be radio pulsars. There is no evidence of radio emission before the 2003 X-ray outburst (unlike ordinary pulsars, which emit radio pulses all the time), and the flux varies from day to day. The flux at all radio frequencies is approximately equal—and at >20 GHz XTE J1810 - 197 is currently the brightest neutron star known. These observations link magnetars to ordinary radio pulsars, rule out alternative accretion models for AXPs, and provide a new window into the coronae of magnetars.
