The disc-jet connection in GRS 1915+105

We have compared simultaneous Ryle Telescope (RT) radio and Rossi X-Ray Timing Explorer (RXTE) X-ray observations of the galactic microquasar GRS 1915+105. We find that radio emission, and therefore also the radio jet, requires the presence of long (~100s), hard dips in the X-ray light curve which seem to have a one-to-one relation with the radio events: each hard dip produces a new radio "flare". We discuss the characteristic features of the connection between the hard X-ray states and the radio emission.