Blackbody Radiation in a Curved Robertson / Walker Background
Abstract
In the standard Friedmann cosmology the blackbody radiation spectrum is usually taken (without explicit proof as far as we know) to have the same familiarT ^{4}form that it has in a flat space. With explicit use of the equation of motion of a quantized massless field propagating in a curved background RobertsonWalker metric we show (for the readily tractable scalar field case) that the assumption is in fact true for an open Universe. For a closed Universe, we find that there is an in principle modification to theT ^{4}law. Unfortunately, the correction turns out to be too small to be experimentally detectable. In passing, we also obtain a simple derivation for the cosmological red shift of frequencies.
 Publication:

Astrophysics and Space Science
 Pub Date:
 July 1987
 DOI:
 10.1007/BF00641561
 Bibcode:
 1987Ap&SS.135..261D
 Keywords:

 Background Radiation;
 Black Body Radiation;
 Cosmology;
 Radiation Spectra;
 SpaceTime Functions;
 Equations Of Motion;
 Metric Space;
 Red Shift;
 Astrophysics