Redemption Ark 2 The Inhibitor Trilogy

In the second book of The Inhibitor Trilogy, Alastair Reynolds pushes the boundaries of science fiction and "confirms his place among the leaders of the hard-science space-opera renaissance" (Publishers Weekly).
Late in the twenty-sixth century, the human race has advanced enough to accidentally trigger the Inhibitors -- alien killing machines designed to detect intelligent life and destroy it. The only hope for humanity lies in the recovery of a secret cache of doomsday weapons -- and a renegade named Clavain who is determined to find them. But other factions want the weapons for their own purposes -- and the weapons themselves have another agenda altogether . . .