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...digerendo la pizza. Characterization of the mid- and far-IR population detected by ISO, Spitzer... and HERSCHEL!!. 10,000. 10 12 L ¤. Z = 0.1. 1000. 0.5. 100. 1. Flux density (mJy). 3. 10. 5. 1. 0.1. 10. 100. 1,000. 10,000. λ ( μ m).
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Characterization of the mid- and far-IR population detected by ISO, Spitzer... and HERSCHEL!!
10,000 1012L¤ Z = 0.1 1000 0.5 100 1 Flux density (mJy) 3 10 5 1 0.1 10 100 1,000 10,000 λ(μm) After Guiderdoni et al. MNRAS 295, 877, 1998 High-z GT Programme Herschel probes the rest-frame bolometric emission from galaxies as they formed most of their stars Will address issues like: • History of star formation and energy production • Structure formation • Cluster evolution • CIRB fluctuations • AGN-starburst connection How? • Investing 850hrs of SPIRE (Hermes) and 650hrs of PACS (PEP) GT • Observing a Set of Blank Fields in Different Depths • Observing a Sample of Rich Clusters (0.2 < z < 1.0)
Clusters GOODS-S 0.04 deg^2 GOODS-N 0.04 deg^2 GOODS-S/Groth/ Lockman 0.25 deg^2 Cosmos/XMM 2 deg^2 XMM/CDFS/Lockman 10 deg^2 ES1/EN1/EN2/XMM/ Lockman ... 50 deg^2 WeddingCake Survey will probe Lbol over a wide redshift range
Name Area Field PACSTime SPIRE Time 70 110 170 250 350 500 - deg^2 - hr hr mJy mJy mJy mJy mJy mJy Clusters - - 80 100 Level 1 0.04 GOODS-S 230 10+30 1.0 1.0 1.0 3.3 4.0 4.6 Level 2 0.04 GOODS-N 27 10 2.0 2.8 3.0 6.7 8.1 9.2 Level 3 0.25 GOODS-S 34 25 2.2 6.2 6.7 10.5 12.7 14.5 0.25 Groth Strip 34 25 2.2 6.2 6.7 10.5 12.7 14.5 0.25 Lockman 34 25 2.2 6.2 6.7 10.5 12.7 14.5 Level 4 2 COSMOS 110 50 6.0 9.8 10.5 21.1 25.5 29.1 2 XMM-LSS 110 50 18 9.8 10.5 21.1 25.5 29.1 Level 5 10 Spitzer 185 200 18 16.9 18.0 23.6 28.5 32.5 Level 6 50 Spitzer - 150 18 - 120 61 74 84 Herschel Extragalactic GT Survey Wedding Cake Time : PACS (659)SPIRE (850) Harwit (10)(Spitzer Depths)
The case for a joint effort • PACS strengths • Excellent spatial resolution • Capabilities for FIR spectroscopy of selected subsamples • SPIRE strengths • Best exploitation of K-correction for high-z sources • Fast mapping speed • Both are needed for characterizing FIR/sub-mm properties of large samples of high-z objects
Redshift distributions Favourable K-corr!! Better resolution!! SPIRE PACS Beam 4.74”@110um 110 micron / 3 mJy / 0.04 deg^2 Beam 24.4”@350um 350 micron / 9 mJy / 0.04 deg^2 Model by Franceschini 2008
GT (PEP & HERMES) SCIENCE GOALS: • Resolve the Cosmic Infrared Background and determine the nature of its constituents. • Determine the cosmic evolution of dusty star formation and of the infrared luminosity function • Elucidate the relation of far-infrared emission and environment, and determine clustering properties • Determine the contribution of AGN
The Cosmic IR Background RadiationResolved Into Sources The integrated extragalactic background light in the far-infrared and sub-millimeter region of the spectrum is approximately equal to the integrated background light in the optical and UV part of the spectrum. To develop a complete understanding of galaxy formation, this background light must be resolved into galaxies and their properties must be characterized.
We expect to resolve about 80%, 85% and 55% of the CIB due to galaxies at 75, 110, and 170 microns into individual 5-sigma detected sources for the blank field surveys. These fractions clearly depend on the faint number counts at these wavelengths that only PACS can measure. Using the wealth of multi-wavelength data already existing in the chosen well-studied fields and techniques like SED fitting, as well as dedicated follow up projects, we will be able to determine the physical nature of these objects, for example redshifts, luminosities, morphologies, masses, star formation histories, and the role of AGN.
How does the star formation rate density and galaxy luminosity function evolve? Luminosity of infrared galaxies detectable in the three PACS bands at different redshifts for a single star-forming SED galaxy
The PEP surveys will sample the critical far-infrared peak of star forming galaxy SEDs and will probe a large part of the infrared luminosity function, down to luminosities of ~1e11 Lsun at redshift 1 and <1e12 Lsun at redshift 2. This will enable a detailed study of the evolution of the infrared luminosity function with redshift, expanding on the results based on mid-infrared or submm surveys and suppressing the associated uncertainties due to extrapolation of the IR SEDs.
The Padova IR evolutionary model (Franceschini et al. 2008, in prep.) • The 2001 phenomenological model (Franceschini et al. 2001) was rather successful in explaining & “exploring” ISO results • Spitzer & SCUBA data (re)-analyses, however, called for a revamp • Through a simple backward evolution approach, FR08 describes available observables (number counts, z-distributions, L-functions, integrated CIRB levels…) in terms of number and luminosity evolution of four populations • slowly or non-evolving disk galaxies [blue dotted lines] • type-1 AGNs evolving as shown by UV and X-ray selected Quasars & Seyferts [green long-short dashed lines] • moderate-luminosity starbursts with peak emission at z ~ 1 [cyan dot-dashed lines] • ultra-luminous starbursts with peak evolution between z = 2 and z = 4 [red long dashed lines]
Spitzer MIPS Counts & redshift distribution : 24 m Most stringent constraint provided by Spitzer to date Vaccari et al 2008, Rodighiero et al 2008 in prep
Far-IR & Sub-mm source counts Vaccari et al in prep., Franceschini et al. in prep SWIRE+FLS SWIRE+GTO CSO SHADES/SCUBA
Z=0-2.5 24 m Luminosity Functions GOODS-S + GOODS-N + SWIRE-VVDS Fields (Rodighiero et al. 2008 in prep) ~ 2000 sources with some of the best spec info available The determination of redshift-dependent Luminosity Functions require large corrections which depend to a large extent on the adopted SED templates, and particularly so for IR Bolometric (8-1000 m) Luminosity Functions
Constraining Bolometric Luminosity Herschel bands at z=1 vs model spectra Herschel bands will be crucial in constraining the bolometric luminosity of galaxies. This will help untangle the contribution of AGN and star-formation cool/warm dust and thus constrain the star-formation history.
What is the role of AGN and how do they co-evolve with galaxies? Recent combined X-ray and Spitzer surveys have revised our view of the history of accretion onto AGN, in particular with respect to the detection of high redshift z~2 obscured AGN activity (e.g. Daddi 2007, Fiore 2007 via stacking analysis). • 1.4°x1.4° XMM COSMOS (Hasinger et al.)
PEP will also probe the far-infrared emission of fully obscured AGN not detected in X-ray surveys. Recent Spitzer mid-IR surveys detected a significant population of obscured AGNs, not accounted for by traditional optical or X-ray selections (e.g. Donley et al. 2005, Lutz et al. 2005, Martinez-Sansigre et al. 2005). In combination with SPIRE, and Spitzer 24 microns data, PEP/PACS will determine the overall SEDs of active galaxies, including AGN mid-IR emission. Hence PEP will quantify the total energetics of the obscured phases in black-hole evolution, as well as of the associated star formation.
The power of multiwavelength studies MKN231 ARP220
Selection of massive high-z obscured AGN and starburst galaxies Rodighiero et al. 2007
Extragalactic Confusion Due to the different slope in counts, the vs bps is not a one-to-one relation, values being generally & consistently worse than bps ones for SPIRE with respect to PACS
A Pre-Launch Consensus Viewon Herschel EG Confusion Limits MEAN +- RMS of various models4 values above are arguablybest pre-launch indication