Malcolm Tobias Washington University mtobias@void.wustl.edu CCTK Hydro Malcolm Tobias Washington University mtobias@void.wustl.edu

CCTK Hydro: A Status Report Contributors: Miguel Alcubierre Gabrielle Allen Bernd Bruegmann Teepanis Chachiyo Thomas Dramlitsch Ed Evans Toni Font Tom Goodale Philip Gressman Paul Lamping Joan Masso Mark Miller Philippos Papadopoulos Ed Seidel Nikolaos Stergioulas Wai-Mo Suen Malcolm Tobias Rob Young

Overview Cactus 3 Computational Modules (thorns) Initial data MAHC hydro Newtonian hydro Boson stars EOS tables Analysis tools Tests Physics Cactus 4 conversion

Initial data Single NS (TOV) Rotating NS Head-on colliding NS Quasi-equil. Data (Meudon Data) PN initial data Test Data (FRW, shockwave) IVP solver Coupled Ham. & mom. Constraints!!! No assumptions of conformal flatness!!!

MAHC hydro HRSC methods coupled to various evolution systems Roe, Marquina, fluxsplit, ENO, HLLE coupled to various evolution systems ADM, Conformal systems, Bona-Masso well tested (gr-qc/9811015)

Newtonian Hydro HRSC methods primarily Roe solver tested on multiple systems single NS head-on NSs orbiting NSs multiple test indicators angular momentum mass energy

Boson stars Coupled to a variety of GR evolution systems stable over a long time scale

EOS tables 1D tables 2D tables tested for polytropic EOS other EOS are in, but not yet tested thermo. consistent interp. 2D tables still under development still need incorporated into evolution eqs.

Analysis tools Apparent horizon finders waveform extraction Newman-Penrose quantities constraint evaluators

Tests gr-qc/9811015 variety of initial data still fighting referee shocktube FRW single static NS boosted NS

Tests: GR-hydro coupling 3 hydro methods tested: Roe, fluxsplit and Marquina 3 GR evolution systems: ADM, BM-Einstein and BM Ricci often different finite-difference schemes (leapfrog, icn, etc.) TEST EVERY COMBINATION OF EACH!!!

Tests: GR-hydro coupling (2nd order time & space)

Tests: boosted NS

Tests: boosted NS

Tests: boosted NS

Physics Phys. Rev. D 58 103002 (1998), gr-qc/9904041, gr- qc/9909059, Shapiro conjecture head-on collision of NS evolution of quasi-equilibrium NS data (just beginning) more on the way ;-) How to do physics with cactus

Physics: head-on collision Shapiro conjecture: can thermal pressure (from shock heating) delay the collapse in the head-on collision of NS s? Conjecture holds regardless of mass. Take 2 1.4 solar mass NS (polytropic EOS, G=2, K=1.16x105 cm5/g/s2), give them a velocity corresponding to Newtonian infall from infinity, solve the IVP and see what happens!

Physics: head-on collision

Physics: head-on collision

Physics: head-on collision

Physics: Meudon data

Physics: How to use Cactus Cactus is not a black box many untested combinations of parameters top down approach check all equations/routines test for consistency of all terms test for convergence bottom up approach make sure results look "reasonable" make sure results are "right"

Cactus 4.0 Most hydro thorns still under conversion What we will gain: AMR infrastructure better interfacing between GR-hydro solvers more users=more developers & debuggers