The interplay of disc wind and dynamical ejecta in the aftermath of neutron star-black hole mergers

Rodrigo Fernández, Eliot Quataert, Josiah Schwab, Daniel Kasen, Stephan Rosswog

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

We explore the evolution of the different ejecta components generated during the merger of a neutron star and a black hole. Our focus is the interplay between material ejected dynamically during the merger, and the wind launched on a viscous time-scale by the remnant accretion disc. These components are expected to contribute to an electromagnetic transient and to produce r-process elements, each with a different signature when considered separately. Here we introduce a two-step approach to investigate their combined evolution, using two- and threedimensional hydrodynamic simulations. Starting from the output of a merger simulation, we identify each component in the initial condition based on its phase-space distribution, and evolve the accretion disc in axisymmetry. The wind blown from this disc is injected into a three-dimensional computational domain where the dynamical ejecta is evolved. We find that the wind can suppress fallback accretion on time-scales longer than ~100 ms. Because of selfsimilar viscous evolution, the disc accretion at late times nevertheless approaches a power-law time dependence ∝t-2.2. This can power some late-time gamma-ray burst engine activity, although the available energy is significantly less than in traditional fallback models. Inclusion of radioactive heating due to the r-process does not significantly affect the fallback accretion rate or the disc wind. We do not find any significant modification to the wind properties at large radius due to interaction with the dynamical ejecta. This is a consequence of the different expansion velocities of the two components.

Original languageEnglish (US)
Pages (from-to)390-402
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume449
Issue number1
DOIs
StatePublished - Feb 23 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Accretion, accretion discs
  • Dense matter
  • Gravitationalwaves
  • Hydrodynamics
  • Neutrinos
  • Nuclear reactions, nucleosynthesis, abundances

Fingerprint Dive into the research topics of 'The interplay of disc wind and dynamical ejecta in the aftermath of neutron star-black hole mergers'. Together they form a unique fingerprint.

  • Cite this