The GW170817/GRB 170817A/AT 2017gfo Association: Some Implications for Physics and Astrophysics
Abstract
On 2017 August 17, a gravitational-wave event (GW170817) and an associated short gamma-ray burst (GRB 170817A) from a binary neutron star merger had been detected. The follow-up optical/infrared observations also identified the macronova/kilonova emission (AT 2017gfo). In this work, we discuss some implications of the remarkable GW170817/GRB 170817A/AT 2017gfo association. We show that the ∼1.7 s time delay between the gravitational-wave (GW) and GRB signals imposes very tight constraints on the superluminal movement of gravitational waves (i.e., the relative departure of GW velocity from the speed of light is ≤slant 4.3× {10}-16) or the possible violation of the weak equivalence principle (i.e., the difference of the gamma-ray and GW trajectories in the gravitational field of the galaxy and the local universe should be within a factor of ∼ 3.4× {10}-9). The so-called Dark Matter Emulators and a class of contender models for cosmic acceleration (“Covariant Galileon”) are ruled out as well. The successful identification of lanthanide elements in the macronova/kilonova spectrum also excludes the possibility that the progenitors of GRB 170817A are a binary strange star system. The high neutron star merger rate (inferred from both the local sGRB data and the gravitational-wave data) together with the significant ejected mass strongly suggest that such mergers are the prime sites of heavy r-process nucleosynthesis.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2017
- DOI:
- 10.3847/2041-8213/aa9e08
- arXiv:
- arXiv:1710.05805
- Bibcode:
- 2017ApJ...851L..18W
- Keywords:
-
- gamma-ray burst: general;
- gravitational waves;
- stars: neutron;
- Astrophysics - High Energy Astrophysical Phenomena;
- General Relativity and Quantum Cosmology
- E-Print:
- 8 pages, 3 figures, Accepted for Publication in ApJL