  The collapsar model, the now leading model for the engine behind gamma-ray
bursts and hypernovae, requires that a star collapses to form a black hole
surrounded by an accretion disk of high-angular momentum material. The current
best theoretical stellar models, however, do not retain enough angular momentum
in the core of the star to make a centrifugally supported disk. In this paper,
we present the first calculations of the helium-star/helium-star merger
progenitors for the collapsar model. These progenitors invoke the merger of two
helium cores during the common envelope inspiral phase of a binary system. We
find that, in some cases, the merger can produce cores that are rotating 3-10
times faster than single stars. He-star/He-star gamma-ray burst progenitors
have a very different redshift distribution than their single-star gamma-ray
burst progenitors and we discuss how gamma-ray burst observations can constrain
these progenitors.
