Speaker
Description
Light (e.g. deuterons, tritons, helions, $\alpha-$particles), and heavy (pasta phases) nuclei exist in nature in core-collapse supernova matter and neutron star (NS) mergers, where temperatures of the order of 50 to 100 MeV may be attained. The appearance of these clusters can modify the neutrino transport, and, therefore, consequences on the dynamical evolution of supernovae and on the cooling of proto-neutron stars are expected. However, a correct estimation of their abundance implies that an in-medium modification of their binding energies is precisely derived. At such high temperatures, other exotic degrees of freedom, such as hyperons and $\Delta-$isobars, may appear.
Magnetars, mainly Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs), belong to a kind of neutron stars with very strong magnetic fields at the surface, up to $10^{14} \sim 10^{15}$ G, and quite long spin periods, of the order of $2 \sim 20$ s. Nowadays, about thirty of such objects have been observed. Moreover, magnetars are good candidates to be a source of continuous gravitational wave emission, and we expect that in the future it will be possible to detect this type of gravitational waves.
In this talk, we will address not only from the theoretical point of view how these clusters and heavy baryons are calculated for warm stellar matter in the framework of relativistic mean-field (RMF) models with in-medium effects, but also how these models are calibrated to experimental data from heavy-ion collisions, measured by the INDRA Collaboration. We show that this in-medium correction, which was not considered in previous analyses from heavy-ion collisions, is necessary, since the observables of the analyzed systems show strong deviations from the expected results for an ideal gas of free clusters. It turns out that the resulting light cluster abundances come out to be in reasonable agreement with constraints at higher density coming from heavy ion collision data.
We are also going to consider nuclear matter in the NS inner crust under the presence of strong magnetic fields within the same RMF framework, and we will show that these strong fields cause an extension of the NS inner crust, with the occurrence of a series of disconnected non-homogeneous matter regions above the one existing for a null magnetic field. The existence of these extra non-homogeneous matter geometries could have a direct effect on the explanation of the magnetic field evolution inside NS.