Poster abstract details

Here I present preliminary results from the first full analysis of X-Ray variability classes in all RXTE archive observations of the BHC IGR J17091-3624. In particular, I highlight the result that hysteretic loops in colour-colour diagrams are executed in different directions in different states; this behaviour is not seen in GRS 1915+105, an object considered analogous to IGR J17091-3624 which shows much of the same complex behaviour. I discuss the implications of this finding on the nature of hard-photon lag in the spectrum of the BHC, and the effects this has on models of the origin of the variability classes.