arXiv subjects

Guilaine Lagache

Publications and source records attributed to Guilaine Lagache.

At least 55 records · Page 3Linked to original sources

arXiv2014

Cross-correlation of cosmic far-infrared background anisotropies with large scale structures

We measure the cross-power spectra between luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS)-III Data Release Eight (DR8) and cosmic infrared background (CIB) anisotropies from Planck and data from the Improved Reprocessing (IRIS) of the Infrared Astronomical Satellite (IRAS) at 353, 545, 857, and 3000 GHz, corresponding to 850, 550, 350 and 100 micron, respectively, in the multipole range 100<l<1000. Using approximately 6.5 10^5 photometrically determined LRGs in 7760 deg^2 of the northern hemisphere in the redshift range 0.45 < z < 0.65, we model the far-infrared background (FIRB) anisotropies with an extended version of the halo model. With these methods, we confirm the basic picture obtained from recent analyses of FIRB anisotropies with Herschel and Planck, that the most efficient halo mass at hosting star forming galaxies is log(M_ eff/M_\odot)=12.84+/-0.15. We estimate the percentage of FIRB anisotropies correlated with LRGs as approximately 11.8 %, 3.9 %, 1.8 %, and 1.0 % of the total at 3000, 857, 545, and 353 GHz, respectively. At redshift z~0.55, the bias of FIRB galaxies with respect to the dark matter density field has the value b_{FIRB}~1.45, and the mean dust temperature of FIRB galaxies is T_d=26 K. Finally, we discuss the impact of present and upcoming cross-correlations with far-infrared background anisotropies on the determination of the global star formation history and the link between galaxies and dark matter.

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arXiv2014

The co-evolution of black hole growth and star formation from a cross-correlation analysis between quasars and the cosmic infrared background

We present the first cross-correlation measurement between Sloan Digital Sky Survey (SDSS) Type 1 quasars and the cosmic infrared background (CIB) measured by Herschel. The distribution of the quasars at 0.15 =1.4) is $11.1^{+1.6}_{-1.4}$, $7.1^{+1.6}_{-1.3}$ and $3.6^{+1.4}_{-1.0}$ mJy at 250, 350 and 500 microns, respectively, while the mean sub-mm flux densities of the DR9 quasars ( =2.5) is $5.7^{+0.7}_{-0.6}$, $5.0^{+0.8}_{-0.7}$ and $1.8^{+0.5}_{-0.4}$ mJy. We find that the correlated sub-mm emission includes both the emission from satellite DSFGs in the same halo as the central quasar and the emission from DSFGs in separate halos (correlated with the quasar-hosting halo). The amplitude of the one-halo term is ~10 times smaller than the sub-mm emission of the quasars, implying the the satellites have a lower star-formation rate than the quasars. The satellite fraction for the DR7 quasars is $0.008^{+0.008}_{-0.005}$ and the host halo mass scale for the central and satellite quasars is $10^{12.36\pm0.87}$ M$_{\odot}$ and $10^{13.60\pm0.38}$ M$_{\odot}$, respectively. The satellite fraction of the DR9 quasars is $0.065^{+0.021}_{-0.031}$ and the host halo mass scale for the central and satellite quasars is $10^{12.29\pm0.62}$ M$_{\odot}$ and $10^{12.82\pm0.39}$ M$_{\odot}$, respectively. Thus, the typical halo environment of the SDSS Type 1 quasars is found to be similar to that of DSFGs, which supports the generally accepted view that dusty starburst and quasar activity are evolutionarily linked.

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arXiv2014

A dynamical transition from atomic to molecular intermediate-velocity clouds

Towards the high galactic latitude sky, the far-infrared (FIR) intensity is tightly correlated to the total hydrogen column density which is made up of atomic (HI) and molecular hydrogen (H$_{2})$. Above a certain column density threshold, atomic hydrogen turns molecular. We analyse gas and dust properties of intermediate-velocity clouds (IVCs) in the lower galactic halo to explore their transition from the atomic to the molecular phase. Driven by observations, we investigate the physical processes that transform a purely atomic IVC into a molecular one. Data from the Effelsberg-Bonn HI-Survey (EBHIS) are correlated to FIR wavebands of the Planck satellite and IRIS. Modified black-body emission spectra are fitted to deduce dust optical depths and grain temperatures. We remove the contribution of atomic hydrogen to the FIR intensity to estimate molecular hydrogen column densities. Two IVCs show different FIR properties, despite their similarity in HI, such as narrow spectral lines and large column densities. One FIR bright IVC is associated with H$_{2}$, confirmed by $^{12}$CO $(1\rightarrow0)$ emission; the other IVC is FIR dim and shows no FIR excess, which indicates the absence of molecular hydrogen. We propose that the FIR dim and bright IVCs probe the transition between the atomic and molecular gas phase. Triggered by dynamical processes, this transition happens during the descent of IVCs onto the galactic disk. The most natural driver is ram pressure exerted onto the cloud by the increasing halo density. Because of the enhanced pressure, the formation timescale of H$_{2}$ is reduced, allowing the formation of large amounts of H$_{2}$ within a few Myr.

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arXiv2013

The redshift-evolution of the distribution of star formation among dark matter halos as seen in the infrared

[Abridged] Recent studies revealed a strong correlation between the star formation rate (SFR) and stellar mass of star-forming galaxies, the so-called star-forming main sequence. An empirical modeling approach (2-SFM) which distinguishes between the main sequence and rarer starburst galaxies is capable of reproducing most statistical properties of infrared galaxies. In this paper, we extend this approach by establishing a connection between stellar mass and halo mass with the technique of abundance matching. Based on a few, simple assumptions and a physically motivated formalism, our model successfully predicts the (cross-)power spectra of the cosmic infrared background (CIB), the cross-correlation between CIB and cosmic microwave background (CMB) lensing, and the correlation functions of bright, resolved infrared galaxies measured by Herschel, Planck, ACT and SPT. We use this model to infer the redshift distribution these observables, as well as the level of correlation between CIB-anisotropies at different wavelengths. We also predict that more than 90% of cosmic star formation activity occurs in halos with masses between 10^11.5 and 10^13.5 Msun. Taking into account subsequent mass growth of halos, this implies that the majority of stars were initially (at z>3) formed in the progenitors of clusters, then in groups at 0.5<z<3 and finally in Milky-Way-like halos at z<0.5. At all redshifts, the dominant contribution to the star formation rate density stems from halos of mass ~10^12 Msun, in which the instantaneous star formation efficiency is maximal (~70%). The strong redshift-evolution of SFR in the galaxies that dominate the CIB is thus plausibly driven by increased accretion from the cosmic web onto halos of this characteristic mass scale. Material available at http://irfu.cea.fr/Sap/Phocea/Page/index.php?id=537.

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arXiv2012

Microwave and radio emission of dusty star-forming galaxies: Implication for the cosmic radio background

We use the most up-to-date cosmological evolution models of star-forming (SF) galaxies and radio sources to compute the extragalactic number counts and the cosmic background from 408MHz to 12THz. The model of SF galaxies reproduces the constraints obtained by Spitzer, Herschel, and ground-based submm/mm experiments: number counts, redshift distribution of galaxies, cosmic background intensity and anisotropies. The template SEDs of this model are extrapolated to the radio adding synchrotron, free-free, and spinning dust emissions. To fix the synchrotron intensity, we use the IR/radio flux ratio, q70, and a spectral index beta=-3. For a constant q70, our model added to the AGN contribution provides a good fit to the number counts from 12THz to 408MHz and to the CIB. Spinning dust accounts for up to 20% of the cosmic microwave background produced by SF galaxies, but for less than 10% of the total background when AGN are included. The SF galaxies account for 77.5% of the number counts at 1.4GHz for a flux of 1e-4Jy. However, the model does not explain the CRB measured with the ARCADE2 experiment. Considering the case when q70 decreases strongly with redshift, this still does not explain the ARCADE2 results. It also yields to an overestimate of the low-flux number counts in the radio. Thus, we rule out a steep variation of q70 with redshift at least for z<3.5. Adding a population of faint SF galaxies at high redshift (Lir<1e11Lsun and 4<z<6), which would reproduce the ARCADE2 results, leads to predictions of the CIB much higher than what is observed, ruling out this as the explanation for the ARCADE2 results. Considering our findings and previous studies, we conclude that if the radio emission measured by ARCADE2 is astrophysical in origin, it has to originate in the Galaxy or in a new kind of radio sources (with no mid- to far-IR counterparts) or emission mechanism still to be discovered.

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arXiv2012

A unified empirical model for infrared galaxy counts based on observed physical evolution of distant galaxies

We reproduce the mid-infrared to radio galaxy counts with a new empirical model based on our current understanding of the evolution of main-sequence (MS) and starburst (SB) galaxies. We rely on a simple Spectral Energy Distribution (SED) library based on Herschel observations: a single SED for the MS and another one for SB, getting warmer with redshift. Our model is able to reproduce recent measurements of galaxy counts performed with Herschel, including counts per redshift slice. This agreement demonstrates the power of our 2 Star-Formation Modes (2SFM) decomposition for describing the statistical properties of infrared sources and their evolution with cosmic time. We discuss the relative contribution of MS and SB galaxies to the number counts at various wavelengths and flux densities. We also show that MS galaxies are responsible for a bump in the 1.4 GHz radio counts around 50 μJy. Material of the model (predictions, SED library, mock catalogs...) is available online at http://irfu.cea.fr/Sap/Phocea/Page/index.php?id=537.

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arXiv2012

An accurate measurement of the anisotropies and mean level of the Cosmic Infrared Background at 100 and 160 um

The measurement of the anisotropies in the cosmic infrared background (CIB) is a powerful mean of studying the evolution of galaxies and large-scale structures. These anisotropies have been measured by a number of experiments, from the far-infrared to the millimeter. One of the main impediments to an accurate measurement on large scales is the contamination of the foreground signal by Galactic dust emission. Our goal is to show that we can remove the Galactic cirrus contamination using HI data, and thus accurately measure the clustering of starburst galaxies in the CIB. We use observations of the ELAIS N1 field at far-infrared (100 and 160μm) and radio (21 cm) wavelengths. We compute the correlation between dust emission, traced by far-infrared observations, and HI gas traced by 21cm observations, and derive dust emissivities that enable us to subtract the cirrus emission from the far-infrared maps. We then derive the power spectrum of the CIB anisotropies, as well as its mean level at 100μm and 160μm. We also combine the HI data and Spitzer total power mode absolute measurements to determine the CIB mean level at 160μm. We find B160=0.77\pm0.04\pm0.12MJy/sr,where the first error is statistical and the second systematic. Combining this measurement with the B100/B160 color of the correlated anisotropies, we also derive the CIB mean at 100 μm, B100=0.24\pm0.08\pm0.04 MJy/sr. This measurement is in line with values obtained with recent models of infrared galaxy evolution and Herschel/PACS data, but is much smaller than the previous DIRBE measurements. The use of high-angular resolution Hi data is mandatory to accurately differentiate the cirrus from the CIB emission. The 100 μm IRAS map (and thus the map developed by Schlegel and collaborators) in such extragalactic fields is highly contaminated by the CIB anisotropies and hence cannot be used as a Galactic cirrus tracer.

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arXiv2012

Where stars form and live at high redshift: clues from the infrared

The relation between dark matter halos and the loci of star formation at high redshift is a pressing question in contemporary cosmology. Matching the abundance of halos to the abundance of infrared (IR) galaxies, we explicit the link between dark matter halo mass (Mh), stellar mass (M*) and star-formation rate (SFR) up to a redshift of 2. Our findings are five-fold. First, we find a strong evolution of the relation between M* and SFR as a function of redshift with an increase of sSFR = SFR/M* by a factor ~30 between z=0 and z= 2.3. Second, we observe a decrease of sSFR with stellar mass. These results reproduce observed trends at redshift z>0.3. Third, we find that the star formation is most efficient in dark matter halos with Mh~5x10^11 Msun, with hints of an increase of this mass with redshift. Fourth, we find that SFR/Mh increases by a factor ~15 between z = 0 and z = 2.3. Finally we find that the SFR density is dominated by halo masses close to ~7x10^11 Msun at all redshift, with a rapid decrease at lower and higher halo masses. Despite its simplicity, our novel use of IR observations unveils some characteristic mass-scales governing star formation at high redshift.

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arXiv2011

POKER: Estimating the power spectrum of diffuse emission with complex masks and at high angular resolution

We describe the implementation of an angular power spectrum estimator in the flat sky approximation. POKER (P. Of k EstimatoR) is based on the MASTER algorithm developped by Hivon and collaborators in the context of CMB anisotropy. It works entirely in discrete space and can be applied to arbitrary high angular resolution maps. It is therefore particularly suitable for current and future infrared to sub-mm observations of diffuse emission, whether Galactic or cosmological.

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arXiv2011

Modeling the evolution of infrared galaxies : clustering of galaxies in the Cosmic Infrared Background

Star-forming galaxies are a highly biased tracer of the underlying dark matter density field. Their clustering can be studied through the cosmic infrared background anisotropies. These anisotropies have been measured from 100 \mum to 2 mm in the last few years. In this paper, we present a fully parametric model allowing a joint analysis of these recent observations. In order to develop a coherent model at various wavelengths, we rely on two building blocks. The first one is a parametric model that describes the redshift evolution of the luminosity function of star-forming galaxies. It compares favorably to measured differential number counts and luminosity functions. The second one is a halo model based description of the clustering of galaxies. Starting from a fiducial model, we investigate parameter degeneracies using a Fisher analysis. We then discuss how halo of different mass and redshift, how LIRGs and ULIRGs, contribute to the CIB angular power spectra. From the Fisher analysis, we conclude that we cannot constrain the parameters of the model of evolution of galaxies using clustering data only. The use of combined data of C\ell, counts and luminosity functions improves slightly the constraints but does not remove any degeneracies. On the contrary, the measurement of the anisotropies allows us to set interesting constraints on the halo model parameters, even if some strong degeneracies remain. Using our fiducial model, we establish that the 1-halo and 2-halo terms are not sensitive to the same mass regime. We also illustrate how the 1-halo term can be misinterpreted with the Poisson noise term. Conclusions. We present a new model of the clustering of infrared galaxies. However such a model has a few limitations, as the parameters of the halo occupation suffer from strong degeneracies.

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arXiv2011

Spitzer Characterization of Dust in the Ionized Medium of the Large Magellanic Cloud

A systematic investigation of dust emission associated with the ionized gas has so far been performed only in our Galaxy and for wavelengths longer than 60 μm. Newly available Spitzer data now offer the opportunity to carry out a similar analysis in the Large Magellanic Cloud (LMC). By cross-correlating Spitzer SAGE (Surveying the Agents of a Galaxy's Evolution) data with the ATCA/Parkes HI 21-cm data, the NANTEN 12CO (J=1-0) data, and both the SHASSA Hα and the Parkes 6-cm data, we investigate the physical properties of dust associated with the different phases of the gas (atomic, molecular and ionized). In particular, we study the presence and nature of dust from 3.6 to 160 μm and for various regimes of the ionized gas, spanning emission measures (EM) from \sim 1 pc cm-6 (diffuse component) to \sim 10^3 pc cm-6 (HII regions). Using a dust emission model, and testing our results with several radiation field spectra, we show that dust in the ionized gas is warmer than dust associated with other phases (atomic and molecular). We also find a decrease of the polycyclic aromatic hydrocarbons (PAH) relative abundance with respect to big grains (BGs), as well as an increase of the near infrared (NIR) continuum. These three results (e.g. warmer temperature, decrease of PAH abundance and increase of the NIR continuum) are found consistently for all regimes of the ionized gas. On the contrary, the molecular phase appears to provide favorable conditions for the survival of PAHs. Furthermore, the very small grain (VSG) relative abundance tends to increase in the ionized phase, especially in bright HII regions. Last but not least, our analysis shows that the emissivity of dust associated with the ionized gas is lower in the LMC than in our Galaxy, and that this difference is not accounted for by the lower metallicity of the LMC.

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arXiv2011

Modeling the evolution of infrared galaxies: A Parametric backwards evolution model

We aim at modeling the infrared galaxy evolution in an as simple as possible way and reproduce statistical properties among which the number counts between 15 microns and 1.1 mm, the luminosity functions, and the redshift distributions. We then aim at using this model to interpret the recent observations (Spitzer, Akari, BLAST, LABOCA, AzTEC, SPT and Herschel), and make predictions for future experiments like CCAT or SPICA. This model uses an evolution in density and luminosity of the luminosity function with two breaks at redshift ~0.9 and 2 and contains the two populations of the Lagache et al. (2004) model: normal and starburst galaxies. We also take into account the effect of the strong lensing of high-redshift sub-millimeter galaxies. It has 13 free parameters and 8 additional calibration parameters. We fit the parameters to the IRAS, Spitzer, Herschel and AzTEC measurements with a Monte-Carlo Markov chain. The model ajusted on deep counts at key wavelengths reproduces the counts from the mid-infrared to the millimeter wavelengths, as well as the mid-infrared luminosity functions. We discuss the contribution to the cosmic infrared background (CIB) and to the infrared luminosity density of the different populations. We also estimate the effect of the lensing on the number counts, and discuss the recent discovery by the South Pole Telescope (SPT) of a very bright population lying at high-redshift. We predict confusion level for future missions using a P(D) formalism, and the Universe opacity to TeV photons due to the CIB.

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arXiv2010

Mid-infrared spectroscopy of Spitzer-selected ultra-luminous starbursts at z~2

We want to study the mid-infrared properties and the starburst and AGN contributions, of 24um sources at z~2, through analysis of mid-infrared spectra combined with millimeter, radio, and infrared photometry. Mid-infrared spectroscopy allows us to recover accurate redshifts. A complete sample of 16 Spitzer-selected sources (ULIRGs) believed to be starbursts at z~2 ("5.8um-peakers") was selected in the (0.5 sq.deg.) J1064+56 SWIRE Lockman Hole field. These sources have S(24um)>0.5mJy, a stellar emission peak redshifted to 5.8um, and r'(Vega)>23. The entire sample was observed with the low resolution units of the Spitzer/IRS infrared spectrograph. These sources have 1.2mm observations with IRAM 30m/MAMBO and very deep 20cm observations from the VLA. Nine of our sources also benefit from 350um observation and detection from CSO/SHARC-II. The entire sample shows good quality IRS spectra dominated by strong PAH features. The main PAH features at 6.2, 7.7, 8.6, and 11.3um have high S/N average luminosities of 2.90, 10.38, 3.62, and 2.29x10^{10}Lsun, respectively. We derived accurate redshifts spanning from 1.75 to 2.28. The average of these redshifts is 2.017. This result confirms that the selection criteria of "5.8um-peakers" associated with a strong detection at 24um are reliable to select sources at z~2. We have analyzed the different correlations between PAH emission and infrared, millimeter, and radio emission. Practically all our sources are strongly dominated by starburst emission. We have also defined two subsamples based on the equivalent width at 7.7um to investigate AGN contributions. Our sample contains strong starbursts and represents a particularly 24um-bright class of SMGs. The very good correlation between PAH and far-IR luminosities is now confirmed in high-z starburst ULIRGs. These sources show a small AGN contribution to the mid-IR, around ~20% in most cases.

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arXiv2010

Submillimeter to centimeter excess emission from the Magellanic Clouds. II. On the nature of the excess

Dust emission at submm to cm wavelengths is often simply the Rayleigh-Jeans tail of dust particles at thermal equilibrium and is used as a cold mass tracer in various environments including nearby galaxies. However, well-sampled spectral energy distributions of the nearby, star-forming Magellanic Clouds have a pronounced (sub-)millimeter excess (Israel et al., 2010). This study attempts to confirm the existence of such a millimeter excess above expected dust, free-free and synchrotron emission and to explore different possibilities for its origin. We model NIR to radio spectral energy distributions of the Magellanic Clouds with dust, free-free and synchrotron emission. A millimeter excess emission is confirmed above these components and its spectral shape and intensity are analysed in light of different scenarios: very cold dust, Cosmic Microwave Background (CMB) fluctuations, a change of the dust spectral index and spinning dust emission. We show that very cold dust or CMB fluctuations are very unlikely explanations for the observed excess in these two galaxies. The excess in the LMC can be satisfactorily explained either by a change of the spectral index due to intrinsic properties of amorphous grains, or by spinning dust emission. In the SMC however, due to the importance of the excess, the dust grain model including TLS/DCD effects cannot reproduce the observed emission in a simple way. A possible solution was achieved with spinning dust emission, but many assumptions on the physical state of the interstellar medium had to be made. Further studies, using higher resolution data from Planck and Herschel, are needed to probe the origin of this observed submm-cm excess more definitely. Our study shows that the different possible origins will be best distinguished where the excess is the highest, as is the case in the SMC.

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arXiv2009

A New Era in Extragalactic Background Light Measurements: The Cosmic History of Accretion, Nucleosynthesis and Reionization

(Brief Summary) What is the total radiative content of the Universe since the epoch of recombination? The extragalactic background light (EBL) spectrum captures the redshifted energy released from the first stellar objects, protogalaxies, and galaxies throughout cosmic history. Yet, we have not determined the brightness of the extragalactic sky from UV/optical to far-infrared wavelengths with sufficient accuracy to establish the radiative content of the Universe to better than an order of magnitude. Among many science topics, an accurate measurement of the EBL spectrum from optical to far-IR wavelengths, will address: What is the total energy released by stellar nucleosynthesis over cosmic history? Was significant energy released by non-stellar processes? Is there a diffuse component to the EBL anywhere from optical to sub-millimeter? When did first stars appear and how luminous was the reionization epoch? Absolute optical to mid-IR EBL spectrum to an astrophysically interesting accuracy can be established by wide field imagingat a distance of 5 AU or above the ecliptic plane where the zodiacal foreground is reduced by more than two orders of magnitude.

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arXiv2009

Serendipity observations of far infrared cirrus emission in the Spitzer Infrared Nearby Galaxies Survey: Analysis of far-infrared correlations

We present an analysis of far-infrared dust emission from diffuse cirrus clouds. This study is based on serendipitous observations at 160 microns at high galactic latitude with the Multiband Imaging Photometer (MIPS) onboard the Spitzer Space Telescope by the Spitzer Infrared Nearby Galaxies Survey (SINGS). These observations are complemented with IRIS data at 100 and 60 microns and constitute one of the most sensitive and unbiased samples of far infrared observations at small scale of diffuse interstellar clouds. Outside regions dominated by the cosmic infrared background fluctuations, we observe a substantial scatter in the 160/100 colors from cirrus emission. We compared the 160/100 color variations to 60/100 colors in the same fields and find a trend of decreasing 60/100 with increasing 160/100. This trend can not be accounted for by current dust models by changing solely the interstellar radiation field. It requires a significant change of dust properties such as grain size distribution or emissivity or a mixing of clouds in different physical conditions along the line of sight. These variations are important as a potential confusing foreground for extragalactic studies.

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arXiv2007

A scene model of exosolar systems for use in planetary detection and characterisation simulations

Instrumental projects that will improve the direct optical finding and characterisation of exoplanets have advanced sufficiently to trigger organized investigation and development of corresponding signal processing algorithms. The first step is the availability of field-of-view (FOV) models. These can then be submitted to various instrumental models, which in turn produce simulated data, enabling the testing of processing algorithms. We aim to set the specifications of a physical model for typical FOVs of these instruments. The dynamic in resolution and flux between the various sources present in such a FOV imposes a multiscale, independent layer approach. From review of current literature and through extrapolations from currently available data and models, we derive the features of each source-type in the field of view likely to pass the instrumental filter at exo-Earth level. Stellar limb darkening is shown to cause bias in leakage calibration if unaccounted for. Occurrence of perturbing background stars or galaxies in the typical FOV is unlikely. We extract galactic interstellar medium background emissions for current target lists. Galactic background can be considered uniform over the FOV, and it should show no significant drift with parallax. Our model specifications have been embedded into a Java simulator, soon to be made open-source. We have also designed an associated FITS input/output format standard that we present here.

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arXiv2006

The Cosmic Infrared Background Resolved by Spitzer. Contributions of Mid-Infrared Galaxies to the Far-Infrared Background

Aims. We quantify the contributions of 24um galaxies to the Far-Infrared (FIR) Background at 70 and 160um. We provide new estimates of the Cosmic Infrared Background (CIB), and compare it with the Cosmic Optical Background (COB). Methods. Using Spitzer data at 24, 70 and 160um in three deep fields, we stacked more than 19000 MIPS 24um sources with S24>60uJy at 70 and 160um, and measured the resulting FIR flux densities. Results. This method allows a gain up to one order of magnitude in depth in the FIR. We find that the Mid-Infrared (MIR) 24um selected sources contribute to more than 70% of the CIB at 70 and 160um. This is the first direct measurement of the contribution of MIR-selected galaxies to the FIR CIB. Galaxies contributing the most to the total CIB are thus z~1 luminous infrared galaxies, which have intermediate stellar masses. We estimate that the CIB will be resolved at 0.9 mJy at 70 and 3 mJy at 160um. By combining the extrapolation of the 24um source counts below 60uJy, with 160/24 and 70/24 colors as measured with the stacking analysis, we obtain lower limits of 7.1+/-1.0 and 13.4+/-1.7 nW/m2/sr for the CIB at 70 and 160um, respectively. Conclusions. The MIPS surveys have resolved more than three quarters of the MIR and FIR CIB. By carefully integrating the Extragalactic Background Light (EBL) SED, we also find that the CIB has the same brightness as the COB, around 24 nW/m2/sr. The EBL is produced on average by 115 infrared photons for one visible photon. Finally, the galaxy formation and evolution processes emitted a brightness equivalent to 5% of the primordial electromagnetic background (CMB).

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