Using observations of the INTErnational Gamma-Ray Astrophysics Laboratory ( INTEGRAL ) , we put upper limits on the gamma-ray and hard X-ray prompt emission associated with the gravitational wave event GW150914 , discovered by the LIGO/Virgo collaboration .
The omni-directional view of the INTEGRAL/SPI-ACS has allowed us to constrain the fraction of energy emitted in the hard X-ray electromagnetic component for the full high-probability sky region of LIGO trigger .
Our upper limits on the hard X-ray fluence at the time of the event range from F _ { \gamma } = 2 \times 10 ^ { -8 } erg cm ^ { -2 } to F _ { \gamma } = 10 ^ { -6 } erg cm ^ { -2 } in the 75 keV - 2 MeV energy range for typical spectral models .
Our results constrain the ratio of the energy promptly released in gamma-rays in the direction of the observer to the gravitational wave energy E _ { \gamma } / E _ { \mathrm { GW } } < 10 ^ { -6 } .
We discuss the implication of gamma-ray limits on the characteristics of the gravitational wave source , based on the available predictions for prompt electromagnetic emission .