6 research outputs found
The Cosmic Far-Infrared Background Buildup Since Redshift 2 at 70 and 160 microns in the COSMOS and GOODS fields
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 function 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/ .Comment: Accepted in Astronomy & Astrophysic
Phytochemical composition and antioxidant activity of medicinal plants collected from the Tunisian flora
SequĂŞncias de lisina digestĂvel para suĂnos de duas linhagens selecionadas para alta deposição de carne
Spitzer 70/160 μm observations of high-redshift ULIRGs and HyLIRGs in the Boötes field
We present new 70 and 160 ÎĽm observations of a sample of extremely red (R - [24] gsim 15 mag), mid-infrared bright, high-redshift (1.7 lsim z lsim 2.8) galaxies. All targets detected in the far-infrared exhibit rising spectral energy distributions (SEDs) consistent with dust emission from obscured active galactic nuclei (AGNs) and/or star-forming regions in luminous IR galaxies (LIRGs). We find that the SEDs of the high-redshift sources are more similar to canonical AGN-dominated local ultraluminous IR galaxies (ULIRGs) with significant warm dust components than to typical local star-forming ULIRGs. The inferred IR (8-1000 ÎĽm) bolometric luminosities are found to be L bol ~ 4 Ă— 1012 L sun to ~3 Ă— 1013 L sun (ULIRGs/hyper-luminous IR galaxies (HyLIRGs)), representing the first robust constraints on L bol for this class of object