WD-BH Merger: Difference between revisions

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|THzCounterpart        = --
|THzCounterpart        = --
|OIRCounterpart        = --
|OIRCounterpart        = --
|XrayCounterpart        = Accretion disk
|XrayCounterpart        = Yes (transient accretion disk)
|GammarayCounterpart    = --
|GammarayCounterpart    = --
|GWCounterpart          = --
|GWCounterpart          = --
|NeutrinoCounterpart    = --
|NeutrinoCounterpart    = --
|References            = http://adsabs.harvard.edu/abs/2018arXiv180804822P, http://adsabs.harvard.edu/abs/2018arXiv180804822P
|References            = http://adsabs.harvard.edu/abs/2018RAA....18...61L
|Comments              = None
|Comments              = None
}}
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== Model Description ==
== Model Description ==


A broader description, observational effects and detailed information.
During the merger of a BH and a WD, a transient accretion disk is expected to form around the BH, which could power a high speed wind around the entire BH-accretion disk system, forming a corona. Closed magnetic field lines, emerging continuously between the accretion disk and the corona, are twisted by the turbulence in the system, leading to the formation of rope-like flux structures in the corona. When the threshold for mass equilibrium is exceeded, the rope is thrust outward as an episodic jet of relativistic magnetized plasma; a so-called "magnetic blob". Before the accretion disk is exhausted, 2 - 3 magnetic blobs could be ejected at different speeds and will collide at a time after ejection. The collision causes catastrophic magnetic reconnection, and the release of magnetic energy is propagated through the magnetized cold plasma of the blob, and converted to particle kinetic energy. The resulting synchrotron maser could power a non-repeating FRB. Note that the accretion disk is advection-dominated. If the disk has a neutron-dominated accretion flow, only a single blob can be ejected within the lifetime of the accretion disk, and thus no collision will take place. X-ray emission from the accretion disk is expected, which will last only as long as the transient disk itself.
This is an FRB model where the merger of two neutron stars would lead to the generation of an isotropic radio pulse.


== Observational Constraints ==
== Observational Constraints ==


In general this model would predict that FRBs arise from old stellar populations where NS-NS binary systems have had time to form and evolve into compact orbits.
The expected duration, frequency and energetics in this scenario are consistent with FRBs, and the event rate of BH-WD mergers is compatible with that expected for non-repeating FRBs.

Latest revision as of 05:57, 11 October 2018





Summary Table
Category Progenitor Type Energy Mechanism Emission Mechanism Counterparts References Brief Comments
LF Radio HF Radio Microwave Terahertz Optical/IR X-rays Gamma-rays Gravitational Waves Neutrinos
Merger WD-BH Single Maser Synch. -- -- -- -- -- Yes (transient accretion disk) -- -- -- http://adsabs.harvard.edu/abs/2018RAA....18...61L None

Definitions: LF Radio (3 MHz to 3 GHz); HF Radio (3 GHz to 30 GHz); Microwave (30 to 300 GHz)


Model Description

During the merger of a BH and a WD, a transient accretion disk is expected to form around the BH, which could power a high speed wind around the entire BH-accretion disk system, forming a corona. Closed magnetic field lines, emerging continuously between the accretion disk and the corona, are twisted by the turbulence in the system, leading to the formation of rope-like flux structures in the corona. When the threshold for mass equilibrium is exceeded, the rope is thrust outward as an episodic jet of relativistic magnetized plasma; a so-called "magnetic blob". Before the accretion disk is exhausted, 2 - 3 magnetic blobs could be ejected at different speeds and will collide at a time after ejection. The collision causes catastrophic magnetic reconnection, and the release of magnetic energy is propagated through the magnetized cold plasma of the blob, and converted to particle kinetic energy. The resulting synchrotron maser could power a non-repeating FRB. Note that the accretion disk is advection-dominated. If the disk has a neutron-dominated accretion flow, only a single blob can be ejected within the lifetime of the accretion disk, and thus no collision will take place. X-ray emission from the accretion disk is expected, which will last only as long as the transient disk itself.

Observational Constraints

The expected duration, frequency and energetics in this scenario are consistent with FRBs, and the event rate of BH-WD mergers is compatible with that expected for non-repeating FRBs.