The project aims to study various aspects of neutron stars (NSs) fostering the investigation of the relevant microphysics and its interplay with the structure and composition of compact stars. This research is related to some of the most active areas in observational and theoretical Astrophysics: the data coming from gravitational-wave (GW) and X-ray detectors have provided new, interesting but potentially conflicting indications concerning for example the radii of compact stars. New data will be obtained in the near future through multi-messenger analysis of mergers, of long GRBs and of SNe, as well as through radio telescopes (SKA) investigating rotational periods, glitches and potentially measuring moments of inertia of compact stars. One of the aims of the collaboration is to help to finalize projects such as eXTP and THESEUS by providing physical cases for investigation.
The main areas in which the collaboration will be active are:
i) the study of the effect of hyperons and delta resonances;
ii) the possibility of deconfining quarks in compact stars, the scenarios in which that process can take place and their phenomenological implications;
iii) the preparation of Equations of State (EoSs) at finite temperature, to be used in the study of mergers and of supernovae explosions;
iv) the study of condensates and their impact on the thermal and rotational evolution of stars.
The main scientific questions the collaboration wants to address are related to the role played by strangeness in compact stars (either in the form of hyperons and/or in the form of strange quark matter) and to that played by the superfluid/superconductive components. In these fields the collaboration has established during the last few years significant and internationally recognized results, in particular by performing numerical simulations of mergers, by investigating the connection between microphysics and observables such as the tidal deformability and the radius, by investigating the problem of hyperon production in NSs using the most recent theories of three-body forces, by relating the mass distribution of NSs to the phenomenology of cooling and glitches. Moreover, some members of the collaboration are directly involved in the analysis of GWs. This expertise and the results already obtained will be crucial in future investigations.