Characterization of the mid- and far-IR Characterization of the mid- and far-IR population detected by ISO, Spitzer...population detected by ISO, Spitzer...and HERSCHEL!!and HERSCHEL!!

High-z GT Programme

Will address issues like:

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)

• History of star formation and energy production• Structure formation • Cluster evolution• CIRB fluctuations• AGN-starburst connection

After Guiderdoni et al. MNRAS 295, 877, 1998

10 100 1,000 10,000

10,000

1000

100

10

1

0.1

1012L¤

Z = 0.1

0.51

3

5

Flu

x d

ensi

ty

(mJy

)λ (μm)

Herschel probes the rest-frame bolometric emission from galaxies as they formed most of their stars

Wedding Cake Survey

GOODS-S 0.04 deg^2 GOODS-N 0.04 deg^2GOODS-S/Groth/

Lockman 0.25 deg^2 Cosmos/XMM 2 deg^2

ES1/EN1/EN2/XMM/ Lockman ... 50 deg^2

will probe Lbol over a wide redshift range

XMM/CDFS/Lockman 10 deg^2

Clusters

Herschel Extragalactic GT Survey Wedding Cake

14.512.710.56.76.22.22534Groth Strip0.25

29.125.521.110.59.81850110XMM-LSS2

14.512.710.56.76.22.22534Lockman0.25

847461120-18150-Spitzer50Level 6

32.528.523.618.016.918200185Spitzer10Level 5

29.125.521.110.59.86.050110COSMOS2Level 4

14.512.710.56.76.22.22534GOODS-S0.25Level 3

9.28.16.73.02.82.01027GOODS-N0.04Level 2

4.64.03.31.01.01.010+30230GOODS-S0.04Level 1

10080--Clusters

mJymJymJymJymJymJyhrhr-deg^2-

50035025017011070SPIRE Time

PACSTime

FieldAreaName

Time : PACS (659) SPIRE (850) Harwit (10) (Spitzer Depths)

The case for a joint effortThe 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

Beam 24.4”@350um

350 micron / 9 mJy / 0.04 deg^2

Beam 4.74”@110um

110 micron / 3 mJy / 0.04 deg^2

PACS SPIRE

Redshift distributionsFavourable K-corr!!Better resolution!!

Model by Franceschini 2008

GT (PEP & HERMES) SCIENCE GOALS: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 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.

The Cosmic IR Background RadiationResolved Into Sources

Lagache, Puget & Dole 2005 (ARAA)

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 μm

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+GTO SWIRE+FLS

SHADES/SCUBACSO

Z=0-2.5 24 μm 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 μm) Luminosity Functions

Constraining Bolometric Luminosity

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.

Herschel bands at z=1vs model spectra

What is the role of AGN and how do they co-evolve with galaxies?

1.4°x1.4° XMM COSMOS (Hasinger et al.)

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).

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

ARP220 MKN231

Selection of

massive high-z

obscured AGN and

starburst galaxies

Rodighiero et al. 2007

Extragalactic ConfusionChannelChannel PACS1PACS1 PACS2PACS2 PACS3PACS3 SPIRE1SPIRE1 SPIRE2SPIRE2 SPIRE3 SPIRE3

μμmm 7070 110110 170170 250250 350350 500500

Beam Beam FWHMFWHM

4 .74”4 .74” 6.96”6.96” 10.76”10.76” 17.1”17.1” 24.4”24.4” 34.6”34.6”

3 3 [mJy] [mJy] 0.06800.068033

0.89790.8979 6.9586.958 18.2618.26 23.8623.86 22.1622.16

4 4 [mJy] [mJy] 0.19620.1962 2.0732.073 12.2012.20 27.8927.89 34.4934.49 31.0331.03

5 5 [mJy] [mJy] 0.36910.3691 3.4543.454 17.5217.52 37.3837.38 44.8344.83 39.5739.57

10 bps 10 bps [mJy][mJy]

0.11000.1100 1.2631.263 7.0907.090 14.0014.00 15.2315.23 13.2313.23

20 bps 20 bps [mJy][mJy]

0.30290.3029 2.7462.746 11.8211.82 20.4920.49 21.6521.65 18.3118.31

30 bps 30 bps [mJy][mJy]

0.48870.4887 4.0344.034 15.2315.23 25.4025.40 26.3426.34 21.4921.49

40 bps 40 bps [mJy][mJy]

0.66560.6656 5.1105.110 18.1218.12 29.1829.18 29.9329.93 24.0924.09

50 bps 50 bps [mJy][mJy]

0.83500.8350 6.1076.107 20.4520.45 32.4732.47 33.0533.05 26.1826.18

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 View

on Herschel EG Confusion Limits

MEAN +- RMS of various models4 values above are arguably

best pre-launch indication