Modified surface redshift of pulsars produced by magnetoplasma

The propagation of photons in the magnetoplasma medium of pulsar magnetosphere is studied in the framework of an effective metric theory. It is found that the surface redshift is induced by two factors: one coming from the gravitational field and another from the magnetoplasma. The magnetoplasma can shift the spectrum, and the modification of surface redshift of pulsars due to associated magnetoplasma can be the same extent as the gravitational redshift in particular cases via calculation.