The Crab Nebula was surprisingly variable from 2001-2010, with less variability before 2001 and since mid-2010. We presented evidence for spectral softening from RXTE, Swift/BAT, and Fermi GBM during the mid-2008-2010 flux decline. We see no clear connections between the hard X-ray variations and the GeV flares
Document ID: 20120015012. M12-1897. The Flaring Crab: Surprise and Impact Meeting; 4-6 Jul. 2012; Rome; Italy.