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 Fγ=2×10−8 erg cm−2 to Fγ=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 Eγ/EGW<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.
@article{arxiv.1602.04180,
title = {INTEGRAL upper limits on gamma-ray emission associated with the gravitational wave event GW150914},
author = {V. Savchenko and C. Ferrigno and S. Mereghetti and L. Natalucci and A. Bazzano and E. Bozzo and S. Brandt and T. J. -L. Courvoisier and R. Diehl and L. Hanlon and A. von Kienlin and E. Kuulkers and P. Laurent and F. Lebrun and J. P. Roques and P. Ubertini and G. Weidenspointner},
journal= {arXiv preprint arXiv:1602.04180},
year = {2016}
}