# Detection of gravitational waves from astronomical sources

The search for gravitational waves has seen a fundamental change in recent years, with the start of the operational phase of the first generation interferometers, LIGO and Virgo, that having reached their nominal sensitivity, began their first scientific runs searching for high frequency gravitational waves in 2009.

From the point of view of astronomical observations, it is fundamental, once an event that may result in gravitational wave emission is detected with telescopes or astronomical satellites, that the search for an associated (if not strictly simultaneous) gravitational wave signal be initiated, possibly making use of positional information for the event. It is also necessary to accurately predict the expected gravitational wave signal. For this reason the development of a detailed theoretical model is aimed at increasing the probability of detection and also gaining a physical understanding of the sources, laying the foundations for gravitational wave astronomy.

The Italian scientific community active is this area is not especially numerous, but carries out an expert role in many areas: many of the most astrophysically significant gravitational wave studies are carried out through INAF. Of relevance to the forthcoming runs of LIGO and Virgo are the recent studies of the possible connection between high energy, paroxysmal events and gravitational waves. Theoretical activity is also very developed. Oscillations of neutron stars are the subject of advanced research. Binary systems made up of massive black holes will be of great importance to the LISA mission. LISA will be able to detect the gravitational waves from these systems to great distances (redshifts z~10-15) and may detect up to a hundred events per year. Detailed numerical simulations are being developed by some groups, to investigate both the astrophysics of binary black hole systems and the possible cosmological impact of these systems. Currently, the large facilities Virgo and LIGO are being used, and in the future, as well as advancements in these structures, the Einstein Telescope and LISA will also be important.