Hard X-ray variability of Magnetar's Tails observed with INTEGRAL

Abstract

Magnetar's persistent emission above 10 keV was recently discovered thanks to the imaging capabilities of the IBIS coded mask telescope on board the INTEGRAL satellite. The only two sources that show some degree of long term variability are SGR 1806-20 and 1RXS J170849.0-400910. We find some indications that variability of these hard tails could be the driver of the spectral variability measured in these sources below 10 keV. In addition we report for the first time the detection at 2.8 sigma level of pulsations in the hard X-ray tail of SGR 1806-20.