Neutrino signatures and the neutrino-driven wind in binary neutron star mergers

L. Dessart, C. D. Ott, Adam S. Burrows, S. Rosswog, E. Livne

Research output: Contribution to journalArticlepeer-review

252 Scopus citations

Abstract

We present VULCAN/2D multigroup flux-limited-diffusion radiation- hydrodynamics simulations of binary neutron star mergers, using the Shen equation of state, covering ≳ 100 ms, and starting from azimuthal-averaged two-dimensional slices obtained from three-dimensional smooth-particle- hydrodynamics simulations of Rosswog & Price for 1.4 M (baryonic) neutron stars with no initial spins, co-rotating spins, or counter-rotating spins. Snapshots are post-processed at 10 ms intervals with a multiangle neutrino-transport solver. We find polar-enhanced neutrino luminosities, dominated by and "νμ" neutrinos at the peak, although νe emission may be stronger at late times. We obtain typical peak neutrino energies for νe, and "νμ" of 12, 16, and 22 MeV, respectively. The supermassive neutron star (SMNS) formed from the merger has a cooling timescale of ≲ 1 s. Charge-current neutrino reactions lead to the formation of a thermally driven bipolar wind with 10 -3 M s-1 and baryon-loading in the polar regions, preventing any production of a γ-ray burst prior to black hole formation. The large budget of rotational free energy suggests that magneto-rotational effects could produce a much-greater polar mass loss. We estimate that ≲ 10-4 M of material with an electron fraction in the range 0.1-0.2 becomes unbound during this SMNS phase as a result of neutrino heating. We present a new formalism to compute the annihilation rate based on moments of the neutrino-specific intensity computed with our multiangle solver. Cumulative annihilation rates, which decay as t -1.8, decrease over our 100 ms window from a few ×1050 to 1049 erg s-1, equivalent to a few ×1054 to 1053 e -e+ pairs per second.

Original languageEnglish (US)
Pages (from-to)1681-1705
Number of pages25
JournalAstrophysical Journal
Volume690
Issue number2
DOIs
StatePublished - 2009

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Gamma rays: bursts
  • Hydrodynamics
  • Neutrinos
  • Stars: neutron
  • Stars: rotation
  • Supernovae: general

Fingerprint Dive into the research topics of 'Neutrino signatures and the neutrino-driven wind in binary neutron star mergers'. Together they form a unique fingerprint.

Cite this