Having analyzed high-resolution observations of extragalactic compact radio sources with modern systems of radio telescopes, we obtained an estimate of the upper limit for the photon electric charge, e γ ≲ 3×10-33 of the elementary charge (assuming the photon charge to be energy independent). This is three orders of magnitude better than the limit obtained from radio pulsar timing. We also set a limit on the charge of a gamma-ray (energy ∼0.1 MeV) photon. In the future, the estimate based on extragalactic sources can be improved significantly.
- Pub Date:
- March 2005
- fundamental constants - radio sources - extragalactic magnetic fields;
- High Energy Physics - Phenomenology;
- Physics - Accelerator Physics
- 12 pages, no figures, accepted to Astronomy Letters