The Impact of a Supernova Remnant on Fast Radio Bursts
Abstract
Fast radio bursts (FRBs) are millisecond bursts of radio radiation whose progenitors, so far, remain mysterious. Nevertheless, the timescales and energetics of these events have lead to many theories associating FRBs with young neutron stars (NSs). Motivated by this, I explore the interaction of FRBs with young supernova remnants (SNRs), and I discuss the potential observational consequences and constraints of such a scenario. As the supernova (SN) ejecta plows into the interstellar medium (ISM), a reverse shock is generated that passes back through the material and ionizes it. This leads to a dispersion measure (DM) associated with the SNR as well as a time derivative for DM. The times when DM is high are generally overshadowed by free-free absorption, which, depending on the mass of the ejecta and the density of the ISM, may be probed at frequencies of 400 {{MHz}}-1.4 {{GHz}} on timescales of ∼100-500 years after the SN. Magnetic fields generated at the reverse shock may be high enough to explain Faraday rotation that has been measured for one FRB. If FRBs are powered by the spin energy of a young NS (rather than by magnetic energy), the NS must have a magnetic field ≲ {10}11{--}{10}12 {{G}} to ensure that it does not spin down too quickly while the SNR is still optically thick at radio frequencies. In the future, once there are distance measurements to FRBs and their energetics are better understood, the spin of the NS can also be constrained.
- Publication:
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The Astrophysical Journal
- Pub Date:
- June 2016
- DOI:
- 10.3847/2041-8205/824/2/L32
- arXiv:
- arXiv:1604.04909
- Bibcode:
- 2016ApJ...824L..32P
- Keywords:
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- pulsars: general;
- radio continuum: general;
- stars: magnetic field;
- stars: neutron;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 5 pages, 5 figures, version accepted for publication in The Astrophysical Journal Letters. Minor changes to text and updated Figure 5, which constrains neutron star properties