German Lugones

Asymmetric Core Combustion in Neutron Stars and a Potential Mechanism for Gamma-Ray Bursts

We study the transition of nuclear matter to strange quark matter (SQM) inside neutron stars (NSs). It is shown that the influence of the magnetic field expected to be present in NS interiors has a dramatic effect on the propagation of a laminar deflagration (widely studied so far), generating a strong acceleration of the flame in the polar direction. This results in a strong asymmetry in the geometry of the just formed core of hot SQM, which resembles a cylinder orientated in the direction of the magnetic poles of the NS. This geometrical asymmetry gives rise to a bipolar emission of the thermal neutrino-antineutrino pairs produced in the process of SQM formation. The ν annihilate into e+e- pairs just above the polar caps of the NS, giving rise to a relativistic fireball, thus providing a suitable form of energy transport and conversion to γ-emission that may be associated to short gamma-ray bursts.

QUARK–DIQUARK MATTER EQUATION OF STATE AND COMPACT STAR STRUCTURE

(abridged) We construct quark-diquark equations of state using the quark mass density-dependent formalism. A region inside a

SUPERNOVAE, PROTONEUTRON STARS AND RELATED HIGH ENERGY PHENOMENA

2-D

Magnetic Fields in the Universe: From Laboratory and Stars to Primordial Structures

parameter space in which this matter is absolutely stable is identified. Motivated by the reported compactness of some neutron star candidates we present stellar sequences and show that the quark-diquark EOSs allow a very compact structure, even in the cases in which the diquark itself is not bound.

QUARK–DIQUARK EQUATIONS OF STATE MODELS: THE ROLE OF INTERACTIONS

We present a brief review of the present status of the standard model of core collapse supernovae and neutron star formation outlining the basic concepts and paying attention to the possibility of a transition to quark matter. We evaluate the consequences of this transition on the whole explosion mechanism, analyze the possible generation of beamed gamma ray bursts, and discuss the nature of the compact star born as a result of the supernova explosion.