New Upper Limits on Intergalactic Infrared Radiation from High-Energy Astrophysics
Abstract
Following our previously proposed technique, we have used the recent γ-ray observations of Mrk 421 obtained by the Whipple Observatory team and the EGRET experiment on Compton Gamma-Ray Observatory as a probe to place significant constraints on the intergalactic infrared energy density. Our 2 σ upper limits are ~10^-8^ W m^-2^ sr^-1^ for the 1-5 micron range. These constraints are much better than those obtained by direct measurements. They rule out more exotic mechanisms for producing a large intergalactic IR flux and are consistent with radiation produced by stars in normal galaxies.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1993
- DOI:
- 10.1086/187035
- Bibcode:
- 1993ApJ...415L..71S
- Keywords:
-
- GALAXIES: QUASARS: GENERAL;
- GALAXIES: QUASARS: INDIVIDUAL NAME: MARKARIAN 421;
- GAMMA RAYS: THEORY;
- INFRARED: GENERAL