A. Kashlinsky 1,2, J. Mather 2, & S. Odenwald 2
1 NORDITA, Copenhagen, Denmark
2 Code 685, Goddard Space Flight Center, Greenbelt, MD, USA
The cosmic infrared background (CIB) radiation is the cosmic repository
for energy release throughout the history of the universe, and is
important to
measure. The spatial fluctuations of the CIB
resulting from galaxy clustering are predicted to be of the order of 5-10%
on scales of a degree, depending on the luminosity and clustering history
of the early universe. Using the data from the COBE DIRBE instrument, we
conducted an all-sky survey at wavelengths 1.25 - 100 
in an attempt
to measure or set limits on the CIB fluctuations. The observational study
is divided into two broad classes depending on the nature of the foregrounds.
In the near-IR, which includes DIRBE bands 1-4, foreground emission
is dominated by small scale structure due to stars in the Galaxy. In the
mid-
to far-IR, at DIRBE Bands 5-8, foregrounds are dominated by the large-scale
features from emission by dust in the Solar system and the Galaxy. At near-IR
we find a strong correlation between the amplitude of the fluctuations in the
patch and Galactic latitude after clipping bright stars
from each patch; we show that this correlation is consistent with what is
to be expected from stars in the Galaxy. After eliminating the patches in the
Galactic plane and those located in the Galactic center direction
we extrapolate robustly the amplitude of the
fluctuations to cosec|b|=0 in order to determine/constrain the isotropic
component that can be ascribed to CIB. This extrapolation
leaves us with a positive isotropic component which we interpret as a
possible
detection of the CIB fluctuations. In the mid- to far-IR we obtain
(low) upper limits on the CIB fluctuations below. The implications of
these numbers for
early galaxy evolution will be briefly discussed.