A new open-source code for spherically symmetric stellar collapse to neutron stars and black holes
We present the new open-source spherically symmetric general-relativistic (GR) hydrodynamics code GR1D. It is based on the Eulerian formulation of GR hydrodynamics (GRHD) put forth by Romero–Ibáñez–Gourgoulhon and employs radial-gauge, polar-slicing coordinates in which the 3+1 equations simplify substantially. We discretize the GRHD equations with a finite-volume scheme, employing piecewise-parabolic reconstruction and an approximate Riemann solver. GR1D is intended for the simulation of stellar collapse to neutron stars and black holes and will also serve as a testbed for modeling technology to be incorporated in multi-D GR codes. Its GRHD part is coupled to various finite-temperature microphysical equations of state in tabulated form that we make available with GR1D. An approximate deleptonization scheme for the collapse phase and a neutrino-leakage/heating scheme for the postbounce epoch are included and described. We also derive the equations for effective rotation in 1D and implement them in GR1D. We present an array of standard test calculations and also show how simple analytic equations of state in combination with presupernova models from stellar evolutionary calculations can be used to study qualitative aspects of black hole formation in failing rotating core-collapse supernovae. In addition, we present a simulation with microphysical equations of state and neutrino leakage/heating of a failing core-collapse supernova and black hole formation in a presupernova model of a 40 M_⊙ zero-age main-sequence star. We find good agreement on the time of black hole formation (within 20%) and last stable protoneutron star mass (within 10%) with predictions from simulations with full Boltzmann neutrino radiation hydrodynamics.
Additional Information© 2010 IOP Publishing Ltd. Received 8 December 2009, in final form 28 March 2010. Published 10 May 2010. We thank the Niels Bohr International Academy for hosting the Microphysics in Computational Relativistics Astrophysics (MICRA) workshop in August 2009 at which much of the work presented here was inspired. It is a pleasure to thank J-M Ib´an˜ez for helpful advice, for providing the original version of the code of Romero et al and for furnishing a copy of Romero's dissertation. We are indebted to M Duez for very valuable help with the derivation of the neutrino source terms. We are furthermore happy to acknowledge helpful exchanges with WDArnett, ABurrows, P Cerd´a-Dur´an, HDimmelmeier, T Fischer, E Gourgoulhon, IHawke, J Lattimer, L Lehner, M Liebend¨orfer, E Livne, C Meakin, S Noble, A Perego, C Pethick, E S Phinney, E Schnetter, S Scheidgger, Y Sekiguchi and S Teukolsky. This work is supported by the National Science Foundation under grant numbers AST-0855535 and OCI-0905046. EOC is supported in part through a post-graduate fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC) and NASA ATP grant NNX07AH06G. We wish to thank Chris Mach for support of our group servers at TAPIR on which much of the code development and testing was carried out. Results presented in this paper were obtained through computations on the NSF Teragrid under grant TG-MCA02N014, on machines of the Louisiana Optical Network Initiative under grant LONI NUMREL04 and at the National Energy Research Scientific Computing Center (NERSC), which is supported by the Office of Science of the US Department of Energy under contract DE-AC03-76SF00098.
Published - OConnor2010p10125Classical_Quant_Grav.pdf