FIRBACK: III. Catalog, source counts, and cosmological implications of the 170 mu m ISO
H. Dole, R. Gispert, G. Lagache, J. L. Puget, F. R. Bouchet, C. Cesarsky, P. Ciliegi, D. L. Clements, M. Dennefeld, F. X. Désert, D. Elbaz, A. Franceschini, B. Guiderdoni, M. Harwit, D. Lemke, A. F. M. Moorwood, S. Oliver, W. T. Reach, M. Rowan-Robinson, M. Stickel;
AaA, 2001, 372, 364
ABSTRACT:The FIRBACK (Far Infrared BACKground) survey is one of the deepest imaging surveys carried out at 170 mu m with ISOPHOT onboard ISO, and is aimed at
the study of the structure of the Cosmic Far Infrared Background.
This
paper provides the analysis of resolved sources.
After a validated process
of data reduction and calibration, we perform intensive simulations to
optimize the source extraction, measure the confusion noise (sigma_c = 45 mJy),
and give the photometric and astrometric accuracies.
196 galaxies with
flux S > 3 sigma_c are detected in the area of 3.89 square degrees.
Counts
of sources with flux S > 4 sigma_c present a steep slope of 3.3 +/- 0.6 on a
differential ``log N-log S'' plot between 180 and 500 mJy.
As a consequence, the
confusion level is high and will impact dramatically on future IR deep
surveys.
This strong evolution, compared with a slope of 2.5 from Euclidian
geometry, is in line with models implying a strongly evolving Luminous Infrared
Galaxy population.
The resolved sources account for less than 10% of the
Cosmic Infrared Background at 170 mu m, which is expected to be resolved into
sources in the 1 to 10 mJy range.
Based on observations with ISO, an ESA project
with instruments funded by ESA Member States (especially the PI countries:
France, Germany, The Netherlands and the UK) and with the participation of ISAS
and NASA..
KEYWORDS: cosmology: miscellaneous, galaxies: infrared, galaxies: evolution, galaxies: statistics
CODE: dole2001