Fully Relativistic Simulations of the Inspiral and Merger of Black Hole - Neutron Star Binaries

Patrick M. Motl1, M. Anderson2, M. Besselman3, S. Chawla2, E. W. Hirschmann3, L. Lehner4, S. L. Liebling5, D. Neilsen3, J. E. Tohline2

1Indiana University Kokomo, 2Louisiana State University, 3Brigham Young University, 4The Perimeter Institute, Canada, 5Long Island University.

Initial Setup

Lorene initial datahttp://www.lorene.obspm.fr

Neutron Star:Irrotational, Γ = 2R = 15 [km]M = 1.4 Msolar

Initial dipole field of strength 1012 [Gauss]

Black Hole:M = 7 MSolar

a = 0, 0.5

Initial separation of 100 [km]Grid extends to ± 443 [km]Peak resolution of 0.73 [km] or 40 points across initial neutron star

Simulations

Explore the parameter space of initial separation {90, 100, 150 [km]}black hole spin {0, 0.5}initial magnetic field {0, 1012 [Gauss]}

Adaptive Mesh Refinement with the had package to couple

Einstein solver: generalized harmonic formalism with excision

MHD solver: High resolution shock-capturing code using PPM reconstruction and HLLE flux

Information about had and the application codes available at http://had.liu.edu

Gravitational Radiation measured from Ψ4

a = 0, B = 1012a = 0.5, B = 0 anda = 0.5, B = 1012

Evolution with a = 0, B = 1012

Evolution with a = 0.5, B = 1012

Evolution with a = 0.5, B = 0

Vertical Structure with a = 0.5

Unmagnetized B = 1012 initially

MDisk = 1.6% MDisk = 1.7%

Summary

Effects from magnetic field appear minimal in these NS+BH binaries at least to this point in the evolution and with this (rather low) resolution.

This work was supported by the NSF through grants PHY-0803629 and PHY-0653375 to LSU. Thanks also to the College of Arts and Sciences at IU Kokomo for their support.

The computations presented here were performed on resources from the Teragrid and the Louisiana Optical Network Initiative (LONI).