The international schools on astroparticle physics (ISAPP, https://www.isapp-schools.org/isapp-schools) are thematic schools lasting 10-15 days, addressed to PhD students and young post-docs. 

The first Virgo and LIGO detections marked the beginning of gravitational-wave astronomy. The detection of a black-hole merger in 2015 and the detection of the coalescence of a binary neutron star (and the associated electromagnetic counterpart) in 2017, have shown the potential of gravitational-wave science for astrophysics, cosmology, nuclear physics, and fundamental physics. After two observing periods (01 and 02), the Virgo and LIGO instruments have been upgraded and the third observing period (03) started in April 2019, with new gravitational-wave candidates detected on a weekly basis. New Virgo and LIGO upgrades are planned in the coming years, as well as a widening of the international network of gravitational wave detectors, with the arrival of KAGRA in Japan and LIGO-India.

This school offers a general overview of the different aspects of gravitational-wave science: a theoretical introduction to gravitational waves and their astrophysical sources, a course on detectors, and finally an overview on data analysis techniques and the scientific implications of the first detections. Future perspectives, covering the instruments and associated science, will also be discussed.

The school will take place in Florence, at the Villa Finaly, an historical place belonging to the Paris Universities. This quiet location, offers the possibility of in-depth discussions among students and between students and teachers.

Lectures will take place in the morning and early afternoon. Then Q/A sessions or time for project development are allocated in the afternoon. Projects (for example, analysis of LIGO and Virgo data) will be developed in groups, with a kick-off at the beginning of the school and a final presentation at the end of the school. In the evening, informal lectures are planned on broader themes, such as the challenges of open data, the management of a large science project, and the science outreach. A visit to the Virgo instrument is also planned.