INTEGRAL observations of the gravitational-wave gamma-ray counterparts

The INTErnational Gamma RAy Laboratory (INTEGRAL) has carried out a search for gamma-ray signals temporally and/or spatially coincident with gravitational-wave (GW) triggers distributed by the LIGO and Virgo collaboration (LVC). Its high duty cycle ( 90%) ensures an ideal coverage; the omni-directional and high sensitivity of the SPI Anti Coincidence shield yield the most stringent constraints on any impulsive gamma-ray signal between 75 keV and 2 MeV, for almost the full sky. The other INTEGRAL instruments, in particular the imager IBIS and its Veto system, provide complementary coverage in the regions with reduced sensitivity for the SPI-ACS.The relative large field of view of the INTEGRAL coded-mask instruments allows us to place stringent limits from 3 keV to 2 MeV for a large part of a GW localization region of a black-hole binary merger, when it is serendipitously covered by planned observations. Moreover, we performed follow-up observations for the most favorable GW triggers, in order to investigate any after-glow-like associated emission.We will report on INTEGRAL gamma-ray observations related to the detection of the neutron-star binary merger GW170817, as well as the non-detections related to the various GW signals from the binary black-hole mergers, and discuss the implications of our findings.