Implications from the Upper Limit of Radio Afterglow Emission of FRB 131104/Swift J0644.5-5111
Abstract
A γ-ray transient, Swift J0644.5-5111, has been claimed to be associated with FRB 131104. However, a long-term radio imaging follow-up observation only placed an upper limit on the radio afterglow flux of Swift J0644.5-5111. Applying the external shock model, we perform a detailed constraint on the afterglow parameters for the FRB 131104/Swift J0644.5-5111 system. We find that for the commonly used microphysics shock parameters (e.g., {ɛ }e=0.1, {ɛ }B=0.01, and p = 2.3), if the fast radio burst (FRB) is indeed cosmological as inferred from its measured dispersion measure (DM), the ambient medium number density should be ≤slant {10}-3 {{cm}}-3, which is the typical value for a compact binary merger environment but disfavors a massive star origin. Assuming a typical ISM density, one would require that the redshift of the FRB be much smaller than the value inferred from DM (z\ll 0.1), implying a non-cosmological origin of DM. The constraints are much looser if one adopts smaller {ɛ }B and {ɛ }e values, as observed in some gamma-ray burst afterglows. The FRB 131104/Swift J0644.5-5111 association remains plausible. We critically discuss possible progenitor models for the system.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2017
- DOI:
- 10.3847/2041-8213/835/2/L21
- arXiv:
- arXiv:1611.06481
- Bibcode:
- 2017ApJ...835L..21G
- Keywords:
-
- gamma-ray burst: general;
- gamma-ray burst: individual: FRB 131104;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Accepted for publication in ApJL