The WE Heraeus Physics School and the 62nd Karpacz Winter School in Theoretical Physics "Multimessenger Astrophysics and Cosmology" will be held from 28 February to 6 March 2026.
Compact stars, dense remnants of supernovae, compress about 1.4 solar masses into a 10 km radius—reaching densities beyond atomic nuclei. Their extreme compactness makes them unique laboratories for high-density matter. Gravitational-wave detections of binary neutron star mergers now allow direct probes of such conditions, with hot, dynamic post-merger remnants offering complementary insight to cold pulsars.
With next-generation observatories like the Einstein Telescope and Cosmic Explorer, multi-messenger astrophysics—combining gravitational waves, electromagnetic signals, and neutrinos—will sharpen constraints on the dense-matter equation of state, extreme gravity, and heavy-element nucleosynthesis. Mergers also serve as standard sirens, enabling independent measurements of the Hubble constant.
The school will cover the thermal history of the Universe after its first second, from the quark–hadron transition to neutrino decoupling, linking microphysics to cosmological observables. Topics include the Hubble tension, modified gravity, primordial magnetic fields, compact-object mergers, future gravitational-wave science, and primordial black holes as dark-matter or galaxy-seed candidates—offering a unified view across astrophysics, cosmology, and particle physics.