The Dynamics of Debris Disk Creation in Neutron Star Mergers
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arXiv
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| Autores principales: | , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2024
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| _version_ | 1866916274217418752 |
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| author | Zenati, Yossef Krolik, Julian Werneck, Leonardo Etienne, Zachariah Noble, Scott Murguia-Berthier, Ariadna Schnittman, Jeremy |
| author_facet | Zenati, Yossef Krolik, Julian Werneck, Leonardo Etienne, Zachariah Noble, Scott Murguia-Berthier, Ariadna Schnittman, Jeremy |
| contents | The detection of GW170817/AT2017gfo inaugurated an era of multimessenger astrophysics, in which gravitational wave and multiwavelength photon observations complement one another to provide unique insight on astrophysical systems. A broad theoretical consensus exists in which the photon phenomenology of neutron star mergers largely rests upon the evolution of the small amount of matter left on bound orbits around the black hole or massive neutron star remaining after the merger. Because this accretion disk is far from inflow equilibrium, its subsequent evolution depends very strongly on its initial state, yet very little is known about how this state is determined. Using both snapshot and tracer particle data from a numerical relativity/MHD simulation of an equal-mass neutron star merger that collapses to a black hole, we show how gravitational forces arising in a non-axisymmetric, dynamical spacetime supplement hydrodynamical effects in shaping the initial structure of the bound debris disk. The work done by hydrodynamical forces is ${\sim}10$ times greater than that due to time-dependent gravity. Although gravitational torques prior to remnant relaxation are an order of magnitude larger than hydrodynamical torques, their intrinsic sign symmetry leads to strong cancellation; as a result, hydrodynamical and gravitational torques have comparable effect. We also show that the debris disk's initial specific angular momentum distribution is sharply peaked at roughly the specific angular momentum of the merged neutron star's outer layers, a few $r_g c$, and identify the regulating mechanism. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_03156 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | The Dynamics of Debris Disk Creation in Neutron Star Mergers Zenati, Yossef Krolik, Julian Werneck, Leonardo Etienne, Zachariah Noble, Scott Murguia-Berthier, Ariadna Schnittman, Jeremy High Energy Astrophysical Phenomena The detection of GW170817/AT2017gfo inaugurated an era of multimessenger astrophysics, in which gravitational wave and multiwavelength photon observations complement one another to provide unique insight on astrophysical systems. A broad theoretical consensus exists in which the photon phenomenology of neutron star mergers largely rests upon the evolution of the small amount of matter left on bound orbits around the black hole or massive neutron star remaining after the merger. Because this accretion disk is far from inflow equilibrium, its subsequent evolution depends very strongly on its initial state, yet very little is known about how this state is determined. Using both snapshot and tracer particle data from a numerical relativity/MHD simulation of an equal-mass neutron star merger that collapses to a black hole, we show how gravitational forces arising in a non-axisymmetric, dynamical spacetime supplement hydrodynamical effects in shaping the initial structure of the bound debris disk. The work done by hydrodynamical forces is ${\sim}10$ times greater than that due to time-dependent gravity. Although gravitational torques prior to remnant relaxation are an order of magnitude larger than hydrodynamical torques, their intrinsic sign symmetry leads to strong cancellation; as a result, hydrodynamical and gravitational torques have comparable effect. We also show that the debris disk's initial specific angular momentum distribution is sharply peaked at roughly the specific angular momentum of the merged neutron star's outer layers, a few $r_g c$, and identify the regulating mechanism. |
| title | The Dynamics of Debris Disk Creation in Neutron Star Mergers |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2404.03156 |