Recent gravitational wave (GW) detections with LIGO/Virgo opened a new window on the Universe, unveiling the most violent catastrophic events in the cosmos. GW astronomy is just in its infancy, 3G detectors will extend our capabilities to observe colliding black holes and neutron stars from the ground, and the Laser Interferometer Space Antenna (LISA) and Pulsar Timing Arrays (PTAs) will offer...
The discovery of the gravitational wave transient GW170817 and its electromagnetic counterparts ushered in a new era of multi-messenger. astrophysics, in which both gravitational waves and light provide complementary views of the same source. These observations gave astronomers the unprecedented opportunity to probe the merger of two neutron stars, solving decade-long mysteries about the...
We exploit observations of the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) to search for gamma-ray and hard X-ray emission associated with the gravitational wave events discovered during scientific runs of Advanced LIGO and Advanced Virgo. The highly eccentric orbit of INTEGRAL ensures high duty cycle, long-term stable background, and unobstructed view of the nearly entire sky....
Supermassive black hole binaries (SMBHB) are a natural outcome of the hierarchical mergers predicted by the $\Lambda$CDM cosmology, and promising sources of nanohertz continuous gravitational wave signals. However, their detection remains elusive. Since hard X-rays are produced in the innermost regions of active galactic nuclei, they are predicted to show the best signatures of SMBHB, namely a...
Fundamental properties of black hole X-ray binaries (BHXBs) are important in massive stellar evolution and high energy astrophysics. But, their astrometric properties have been reported for a handful of objects, because their transient behavior, faint optical counterparts and large distances (> 1 kpc) have made comprehensive astrometric investigations of BHXBs very challenging. Gaia has...
The tidal disruption of a star by a massive black hole is a rare event that results in a spectacular flare of electromagnetic radiation. Visible from radio to X-ray wavelengths, tidal disruption flares are a unique probe to study massive black holes and the nucleus of their host galaxies. The advent of optical transient surveys has accelerated this field; the increased detection rate has...
When a star is disrupted by a super-massive black hole (SMBH), the stellar debris returns to the black hole at a rate which exceeds the Eddington accretion rate in the majority of cases and can cause a large X-ray flare. The X-ray emission from the resultant thick disk, shares characteristics with that seen from highly-accreting, low black hole mass ($10^5$ to $10^7$ solar masses), AGN; namely...
XMM-Newton's large field of view and excellent sensitivity have resulted in hundreds of thousands of serendipitous X-ray detections, all publicly available in the latest version of the catalogue, 3XMM-DR8. Amongst these detections, many variable sources have been identified, including gamma-ray bursts, cataclysmic variables, supernova, magnetars, X-ray binaries and tidal disruption events. I...
Simultaneous O-IR / X-ray high-time resolution observations are one of the most powerful tools to study jets in Low-mass X-ray binareis. In this talk I present the latest results regarding fast-IR variabilty of the new black-hole transients which went in outburt between 2017 and today (e.g. MAXI J1535-571, MAXI J1820+070 and MAXI 1348-630). All these sources have been oberved in IR (K band)...
