The Cosmic Far-Infrared Background (CIB) at wavelengths around 160 {mu}m corresponds to the peak intensity of the whole Extragalactic Background Light, which is being measured with increasing accuracy. However, the build up of the CIB emission as a f
unction of redshift, is still not well known. Our goal is to measure the CIB history at 70 {mu}m and 160 {mu}m at different redshifts, and provide constraints for infrared galaxy evolution models. We use complete deep Spitzer 24 {mu}m catalogs down to about 80 {mu}Jy, with spectroscopic and photometric redshifts identifications, from the GOODS and COSMOS deep infrared surveys covering 2 square degrees total. After cleaning the Spitzer/MIPS 70 {mu}m and 160 {mu}m maps from detected sources, we stacked the far-IR images at the positions of the 24 {mu}m sources in different redshift bins. We measured the contribution of each stacked source to the total 70 and 160 {mu}m light, and compare with model predictions and recent far-IR measurements made with Herschel/PACS on smaller fields. We have detected components of the 70 and 160 {mu}m backgrounds in different redshift bins up to z ~ 2. The contribution to the CIB is maximum at 0.3 <= z <= 0.9 at 160{mu}m (and z <= 0.5 at 70 {mu}m). A total of 81% (74%) of the 70 (160) {mu}m background was emitted at z < 1. We estimate that the AGN relative contribution to the far-IR CIB is less than about 10% at z < 1.5. We provide a comprehensive view of the CIB buildup at 24, 70, 100, 160 {mu}m. IR galaxy models predicting a major contribution to the CIB at z < 1 are in agreement with our measurements, while our results discard other models that predict a peak of the background at higher redshifts. Our results are available online http://www.ias.u-psud.fr/irgalaxies/ .
BLAST (Balloon-borne Large-Aperture Submillimeter Telescope) performed the first deep and wide extragalactic survey at 250, 350 and 500 um. The extragalactic number counts at these wavelengths are important constraints for modeling the infrared galax
ies evolution. [...] We use three methods to identify the submillimeter sources. 1) Blind extraction. [...] The photometry is computed with a new simple and quick PSF fitting routine (FASTPHOT). [...] 2) Extraction with prior. [...] 3) A stacking analysis. [...] With the blind extraction, we reach 97, 83 and 76 mJy at resp. 250, 350 and 500 um with a 95% completeness. With the prior extraction, we reach 76 mJy (resp. 63 and 49 mJy) at 250 um (resp. 350 and 500 um). With the stacking analysis, we reach 6.2 mJy (resp. 5.2 and 3.5 mJy) at 250 um (resp. 350 and 500 um). The differential submillimeter number counts are derived, and start showing a turnover at flux densities decreasing with increasing wavelength. There is a very good agreement with the P(D) analysis of Patanchon et al. (2009). At bright fluxes (>100 mJy), the Lagache et al. (2004) and Le Borgne et al. (2009) models slightly overestimate the observed counts, but there is a very good agreement near the peak of differential number counts. [...] Counts are available at: http://www.ias.u-psud.fr/irgalaxies/downloads.php
We present the observed correlations between rest-frame 8, 24, 70 and 160 um monochromatic luminosities and measured total infrared luminosities L_IR of galaxies detected by Spitzer. Our sample consists of 372 star-forming galaxies with individual de
tections and flux measurements at 8, 24, 70 and 160 um. We have spectroscopic redshifts for 93% of these sources, and accurate photometric redshifts for the remainder. We also used a stacking analysis to measure the IR fluxes of fainter sources at higher redshifts. We show that the monochromatic mid and far-infrared luminosities are strongly correlated with the total infrared luminosity and our stacking analysis confirms that these correlations also hold at higher redshifts. We provide relations between monochromatic luminosities and total infrared luminosities L_IR that should be reliable up to z~2 (z~1.1) for ULIRGs (LIRGs). In particular, we can predict L_IR with accuracies of 37% and 54% from the 8 and 24 um fluxes, while the best tracer is the 70 um flux. Combining bands leads to slightly more accurate estimates. For example, combining the 8 and 24 um luminosities predicts L_IR with an accuracy of 34%. Our results are generally compatible with previous studies, and the small changes are probably due to differences in the sample selection criteria. We can rule out strong evolution in dust properties with redshift up to z~1. Finally, we show that infrared and sub-millimeter observations are complementary means of building complete samples of star-forming galaxies, with the former being more sensitive for z<~2 and the latter at higher z>~2.
