Artist's impression of a magnetar.
Magnetars are the cosmic objects with the strongest magnetic fields ever measured in the Universe. They are extremely magnetised pulsars – the hot and dense remnants of massive stars that throw off energetic radiation in impulsive bursts and longer outbursts on timescales from milliseconds to years.
A multi-instrument campaign led by ESA’s XMM-Newton has captured an outburst emanating from the youngest baby pulsar ever spotted: Swift J1818.0−1607, which is interestingly also a magnetar.
More information: XMM-Newton spies youngest baby pulsar ever discovered