  Mergers of stellar-mass black holes (BHs), such as GW150914 observed by LIGO,
are not expected to have electromagnetic counterparts. However, the Fermi GBM
detector identified of a gamma-ray transient 0.4 s after the gravitational wave
(GW) signal GW150914 with consistent sky localization. I show that the two
signals might be related if the BH binary detected by LIGO originated from two
clumps in a dumbbell configuration that formed when the core of a rapidly
rotating massive star collapsed. In that case, the BH binary merger was
followed by a gamma-ray burst (GRB) from a jet that originated in the accretion
flow around the remnant BH. A future detection of a GRB afterglow could be used
to determine the redshift and precise localization of the source. A population
of standard GW sirens with GRB redshifts would provide a new approach for
precise measurements of cosmological distances as a function of redshift.
