@article{perego_hempel_froehlich_ebinger_eichler_casanova_liebendoerfer_thielemann_2015, title={PUSHING CORE-COLLAPSE SUPERNOVAE TO EXPLOSIONS IN SPHERICAL SYMMETRY. I. THE MODEL AND THE CASE OF SN 1987A}, volume={806}, ISSN={["1538-4357"]}, url={http://dx.doi.org/10.1088/0004-637x/806/2/275}, DOI={10.1088/0004-637x/806/2/275}, abstractNote={We report on a method, PUSH, for triggering core-collapse supernova explosions of massive stars in spherical symmetry. We explore basic explosion properties and calibrate PUSH such that the observables of SN1987A are reproduced. Our simulations are based on the general relativistic hydrodynamics code AGILE combined with the detailed neutrino transport scheme IDSA for electron neutrinos and ALS for the muon and tau neutrinos. To trigger explosions in the otherwise non-exploding simulations, we rely on the neutrino-driven mechanism. The PUSH method locally increases the energy deposition in the gain region through energy deposition by the heavy neutrino flavors. Our setup allows us to model the explosion for several seconds after core bounce. We explore the progenitor range 18-21M$_{\odot}$. Our studies reveal a distinction between high compactness (HC) and low compactness (LC) progenitor models, where LC models tend to explore earlier, with a lower explosion energy, and with a lower remnant mass. HC models are needed to obtain explosion energies around 1 Bethe, as observed for SN1987A. However, all the models with sufficiently high explosion energy overproduce $^{56}$Ni. We conclude that fallback is needed to reproduce the observed nucleosynthesis yields. The nucleosynthesis yields of $^{57-58}$Ni depend sensitively on the electron fraction and on the location of the mass cut with respect to the initial shell structure of the progenitor star. We identify a progenitor and a suitable set of PUSH parameters that fit the explosion properties of SN1987A when assuming 0.1M$_{\odot}$ of fallback. We predict a neutron star with a gravitational mass of 1.50M$_{\odot}$. We find correlations between explosion properties and the compactness of the progenitor model in the explored progenitors. However, a more complete analysis will require the exploration of a larger set of progenitors with PUSH.}, number={2}, journal={ASTROPHYSICAL JOURNAL}, author={Perego, A. and Hempel, M. and Froehlich, C. and Ebinger, K. and Eichler, M. and Casanova, J. and Liebendoerfer, M. and Thielemann, F. -K.}, year={2015}, month={Jun} }
 @article{froehlich_casanova_hempel_liebendoerfer_melton_perego_2014, title={Neutrinos and nucleosynthesis in core-collapse supernovae}, volume={1604}, ISSN={["0094-243X"]}, DOI={10.1063/1.4883428}, abstractNote={Massive stars (M > 8-10 M⊙) undergo core collapse at the end of their life and explode as supernova with ∼ 1051 erg of kinetic energy. While the detailed supernova explosion mechanism is still under investigation, reliable nucleosynthesis calculations based on successful explosions are needed to explain the observed abundances in metal-poor stars and to predict supernova yields for galactic chemical evolution studies. To predict nucleosynthesis yields for a large number of progenitor stars, computationally efficient explosion models are required. We model the core collapse, bounce and subsequent explosion of massive stars assuming spherical symmetry and using detailed microphysics and neutrino physics combined with a novel method to artificially trigger the explosion (PUSH). We discuss the role of neutrinos, the conditions in the ejecta, and the resulting nucleosynthesis.}, journal={WORKSHOP ON DARK MATTER, NEUTRINO PHYSICS AND ASTROPHYSICS CETUP 2013: VIITH INTERNATIONAL CONFERENCE ON INTERCONNECTIONS BETWEEN PARTICLE PHYSICS AND COSMOLOGY PPC 2013}, author={Froehlich, C. and Casanova, J. and Hempel, M. and Liebendoerfer, M. and Melton, C. A. and Perego, A.}, year={2014}, pages={178–184} }