FIRAS Overview

FIRAS (Far Infrared Absolute Spectrophotometer) - The cosmic microwave background (CMB) spectrum is that of a nearly perfect blackbody with a temperature of 2.725 +/- 0.002 K. This observation matches the predictions of the hot Big Bang theory extraordinarily well, and indicates that nearly all of the radiant energy of the Universe was released within the first year after the Big Bang.

FIRAS the Movie
This is a movie showing Mollweide full sky images of FIRAS data in Galactic coordinates. The movie steps through the frequencies from 60 GHz to 3 THz. The CMB dipole dominates at low frequencies, Galactic continuum emission becomes stronger with increasing frequency, Galactic [CII] line emission is seen at 1.9 THz, and noise in the FIRAS data increases at the highest frequencies. The movie was made from FIRAS destriped sky spectra with a 2.72 K black body subtracted for each pixel, which generally leaves the data positive. The data in each image were then multiplied by 1/frequency to put all frequencies on approximately the same scale, and finally a square root was applied to reduce the emphasis on the high intensity Galactic plane. Color Video Link / Greyscale video link

A service of the HEASARC and of the Astrophysics Science Division at NASA/GSFC
Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Andrew F. Ptak
LAMBDA Director: Dr. Thomas M. Essinger-Hileman
NASA Official: Dr. Thomas M. Essinger-Hileman
Web Curator: Mr. Michael R. Greason