| 1. |
- Fischer, Tobias, et al.
(författare)
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Core collapse supernovae in the QCD phase diagram
- 2012
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Ingår i: Physics of Atomic Nuclei. - 1063-7788 .- 1562-692X. ; 75:5, s. 613-620
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Tidskriftsartikel (refereegranskat)abstract
- We compare two classes of hybrid equations of state with a hadron-to-quark matter phase transition in their application to core collapse supernova simulations. The first one uses the quark bag model and describes the transition to three-flavor quark matter at low critical densities. The second one employs a Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model with parameters describing a phase transition to two-flavor quark matter at higher critical densities. These models possess a distinctly different temperature dependence of their transition densities which turns out to be crucial for the possible appearance of quark matter in supernova cores. During the early post-bounce accretion phase quark matter is found only if the phase transition takes place at sufficiently low densities as in the study based on the bag model. The increase critical density with increasing temperature, as obtained for our PNJL parametrization, prevents the formation of quark matter. The further evolution of the core collapse supernova as obtained applying the quark bag model leads to a structural reconfiguration of the central protoneutron star where, in addition to a massive pure quark matter core, a strong hydrodynamic shock wave forms and a second neutrino burst is released during the shock propagation across the neutrinospheres. We discuss the severe constraints in the freedom of choice of quark matter models and their parametrization due to the recently observed 2M ⊙ pulsar and their implications for further studies of core collapse supernovae in the QCD phase diagram.
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| 2. |
- O'Connor, Evan, et al.
(författare)
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Global comparison of core-collapse supernova simulations in spherical symmetry
- 2018
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 45:10
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Tidskriftsartikel (refereegranskat)abstract
- We present a comparison between several simulation codes designed to study the core-collapse supernova mechanism. We pay close attention to controlling the initial conditions and input physics in order to ensure a meaningful and informative comparison. Our goal is three-fold. First, we aim to demonstrate the current level of agreement between various groups studying the corecollapse supernova central engine. Second, we desire to form a strong basis for future simulation codes and methods to compare to. Lastly, we want this work to be a stepping stone for future work exploring more complex simulations of core-collapse supernovae, i.e., simulations in multiple dimensions and simulations with modern neutrino and nuclear physics. We compare the early (first similar to 500 ms after core bounce) spherically-symmetric evolution of a 20 M-circle dot progenitor star from six different core-collapse supernovae codes: 3DnSNeIDS A, AGILE-BOLTZTRAN, FLASH, FORNAX, GR1D, and PROMETHEUS-VERTEX. Given the diversity of neutrino transport and hydrodynamic methods employed, we find excellent agreement in many critical quantities, including the shock radius evolution and the amount of neutrino heating. Our results provide an excellent starting point from which to extend this comparison to higher dimensions and compare the development of hydrodynamic instabilities that are crucial to the supernova explosion mechanism, such as turbulence and convection.
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