Tentative detection of a cosmic far-infrared background with COBE.
J. L. Puget, A. Abergel, J. P. Bernard, F. Boulanger, W. B. Burton, F. X. Desert, D. Hartmann;
AaA, 1996, 308, L5
ABSTRACT:We have searched for an extragalactic far infrared background in the whole sky survey of the Cosmic Background Explorer (COBE) Satellite, using
data from the Far Infrared Absolute Spectrometer (FIRAS) instrument.
We
model and remove the interplanetary and interstellar dust components for
all wavelengths above 140microns and below a few millimetres.
The new
Leiden/Dwingeloo HI survey is used for the interstellar cirrus component.
A component
associated with the HII medium is also removed.
It is found that the residues of the
subtraction method have a significant positive value at all wavelengths.
This
emission is isotropic and clearly shows an excess in the submillimeter over the
HI associated dust emission spectrum that cannot be explained by known or
suspected solar or galactic components.
We therefore suggest that it could be
the cosmic far infrared background due to early galaxies that has long been
predicted.
Its rather large intensity can be represented by
{nu}B_{nu}_~3.4x10^-9^({lamdba}/400{mu}m)^-3^W/(m^2^.sr) in the 400-1000{mu}m range and levelling off at shorter
wavelengths.
It implies that a large fraction of the radiation of early galaxies has
been converted in the far IR.
The spectrum seems to indicate the presence of
sources at large redshifts (typically z~3-10).
KEYWORDS: cosmology: observations, diffuse radiation, galaxy: formation
PERSOKEY:cib, cobe, ,
CODE: puget96