A new transient source, identified as IGR J18245-2452, was first detected in X-rays on 28 March 2013 by INTEGRAL in the globular cluster M28, which lies in the constellation Sagittarius. Observations by XMM-Newton determined the pulsar's spin period to be 3.9 milliseconds clearly identifying it as an X-ray-bright millisecond pulsar powered by accretion of material from a nearby low-mass star companion. The spin period and other key characteristics was found to match perfectly those of a pulsar in M28 that had been observed in 2006, but only at radio wavelengths. This is then the first ever fast-spinning 'millisecond pulsar' caught in a crucial evolutionary phase, as it swings between emitting pulses of X-rays and radio waves. |
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ABSTRACT
Animation of a pulsar spun-up by accretion from a companion star This animation shows a slowing down radio pulsar which is then reaccelerated by accretion of gas from a companion star. Watch the full animation on the ESA site. Credits: ESA |
The discovery of IGR J18245-2452 Two IBIS/ISGRI images of the region on the sky where IGR J18245-2452 was discovered (20-40 keV energy band). The top panel shows how the region appeared on 18 February 2013, the bottom panel from 29 March 2013 to 6 April 2013. Both images have an exposure time of about one day and show how the hard X-ray sky is variable. Credits: ISDC/C. Ferrigno |
by Carlo Ferrigno on 2013-09-26 | >> INTEGRAL science results | >> All science results |