Post-Newtonian SPH calculations of binary neutron star coalescence: Method and first results

Joshua A. Faber*, Frederic A. Rasio

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


We present the first results from our post-Newtonian (PN) smoothed particle hydrodynamics (SPH) code, which has been used to study the coalescence of binary neutron star (NS) systems. The Lagrangian particle-based code incorporates consistently all lowest-order (IPN) relativistic effects, as well as gravitational radiation reaction, the lowest-order dissipative term in general relativity. We test our code on sequences of single NS models of varying compactness, and we discuss ways to make PN simulations more relevant to realistic NS models. We also present a PN SPH relaxation procedure for constructing equilibrium models of synchronized binaries, and we use these equilibrium models as initial conditions for our dynamical calculations of binary coalescence. Though unphysical, since tidal synchronization is not expected in NS binaries, these initial conditions allow us to compare our PN work with previous Newtonian results. We compare calculations with and without 1PN effects, for NS svith stiff equations of state, modeled as polytropes with Γ = 3. We find that 1PN effects can play a major role in the coalescence, accelerating the final inspiral and causing a significant misalignment in the binary just prior to final merging. In addition, the character of the gravitational wave signal is altered dramatically, showing strong modulation of the exponentially decaying wave form near the end of the merger. We also discuss briefly the implications of our results for models of gamma-ray bursts at cosmological distances.

Original languageEnglish (US)
Article number064012
Pages (from-to)1-23
Number of pages23
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number6
StatePublished - Sep 15 2000

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


Dive into the research topics of 'Post-Newtonian SPH calculations of binary neutron star coalescence: Method and first results'. Together they form a unique fingerprint.

Cite this