Neutron Stars and Black Holes as Natural Laboratories of Fundamental Physics

The statistics of particles with half-integer spin was constructed in 1926 in the works of E. Fermi and P. A. M. Dirac. Soon after, it was realized that these statistics are extremely important for building a theory of such compact objects as white dwarfs. In this case, there is a limit to the mass of such objects, which is called the Chandrasekhar’s limit. The neutron was discovered by Chadwick in 1932, and already in 1933 Baade and Zwicky suggested that there are neutron stars that arise as a result of supernova explosions and the collapse of a massive core. Pulsars were discovered in 1968 and it was soon realized that pulsars are neutron stars with giant magnetic fields. Binary neutron stars (both in the binary pulsar system and in the kilonova explosion event GW170817) played a key role in the detection of gravitational radiation predicted by general relativity. In 1963, quasars were discovered—fairly compact objects with a gigantic energy release and located at a cosmological distance. It was soon realized that the most natural model of quasars involved a supermassive black hole. Observations of the motions of bright stars in the vicinity of the Galactic center and reconstruction of shadows in the center of the M87 galaxy and the center of our Galaxy based on observations of synchrotron radiation at a wavelength of 1.3 mm provide additional confirmation of the presence of supermassive black holes in the centers of these galaxies.