Introduction to gravitational wave detection and Advanced Virgo Status and perspectives

The present year has seen the announcement by the LIGO-Virgo collaboration of the discovery of gravitational waves with the confirmation of more than one event detected. These detections are a success after half a century of experimental investigations and represent the starting point of a new astronomy era, where a network of gravitational waves observatory are expected to be capable of pointing the source and trigger the so-called multi-messenger astronomy for the searches of electromagnetic or other radiation counterparts. The signal detection has been done by the two ADV-LIGO detectors [The LIGO Scientific Collaboration and the Virgo Collaboration, Phys. Rev. Lett. 116, 061102 (2016); The LIGO Scientific Collaboration and the Virgo Collaboration, Phys. Rev. Lett. 116, 241103 (2016)] while the Virgo detector was ultimating the construction of the ADV-Virgo detector; once that also ADV-Virgo will be operative the network for pointing the source will be completed. In this paper we report briefly on the history of gravitational wave detection and we will focus on the Adv-Virgo apparatus, describing the optical scheme, the critical experimental points and the expected sensitivity.