Evolution of the comoving infraredenergy density up to z~1

* Emeric Le Floc’h, Casey Papovich, Eiichi Egami, George Rieke & the MIPS team (Steward Observatory, University of Arizona)

What can we learn from Spitzer ?

Rencontres de Moriond, March 6-12th 2005

* Hervé Dole & Guilaine Lagache (IAS-Orsay)

Chandra Deep Field South, MIPS 24μm

* Eric Bell (MPIA)

Redshift distribution @ 24μm

Rencontres de Moriond, March 6-12th 2005

- Chary et al. 2004- Gruppioni et al. 2005- Lagache et al. 2004- Pearson 2005

Predictions for flux limit : 80 μJy

(also Lewis et al. 2005)

Courtesy R.Chary/C.Gruppioni/C.Pearson

Chandra Deep Field South 24μm

Integ. time : 1380s / sky pixel 5 ~ 80 μJy ( ~5 sources / arcmin )2

~20’

Rencontres de Moriond, March 6-12th 2005

Chandra Deep Field South 24μm

Rencontres de Moriond, March 6-12th 2005

5589 MIPS sources

* 465 with spec z* 2170 with phot z (total 2635 with redshift)

MIPS 24μm

775 arcmin2

Le Fèvre et al. Vanzella et al.Szokoly et al. Wolf et al.

R-band mag versus Flux@24μm

Rencontres de Moriond, March 6-12th 2005

80% completeness limit at 24μm

VERY hard to be complete in the redshift identification at any 24μm flux, using VVDS/GOODS/COMBO-17

Rencontres de Moriond, March 6-12th 2005

Characterization of the completeness

Redshift identification (24μm-selected)

MIPS sourcehistograms

Complete identification up to z~0.8

Phot. z versus Spec. z

Rencontres de Moriond, March 6-12th 2005

Optically-selected sources MIPS sources

(COMBO-17 versus VVDS)

.

COMBO-17 photo. z

Rencontres de Moriond, March 6-12th 2005

Optically-selected sources

MIPS sources

Photometric redshift classification not dependent on the infrared luminosity

(IR emission very localized, does not affect the SED of the host galaxy)

Photo-z uncertainties:

<z> < 0.04 for R<22mag <z> < 0.09 for R<24mag

Rencontres de Moriond, March 6-12th 2005

Redshift distribution

~55% of 24μm sources at z<1 (flux 80μJy)

COMBO-17

VVDS

MIPSRedshift

CDFS

Total COMBO-17 (3 fields 30’x30’)

B-b

an

d l

um

in.

de

ns

ity

R<25.5

M <-16B

Rencontres de Moriond, March 6-12th 2005

Cumulative counts

~85% identified with R<25.5

optical counterparts

averaged over5 fields

(Papovich et al.)

observed in CDFS

CDFS underdensity

Cumulative counts

Rencontres de Moriond, March 6-12th 2005

Lagache et al.

Pearson

Gruppioni et al.

Chary et al.

15 10 5Wavelength

F

.

LIRGs

ULIRGsF = 0.3mJy

F = 0.08mJy24μm

24μm

Rencontres de Moriond, March 6-12th 2005

24 μm IR luminosity ?

IR luminosities in the CDFS

2635 sourceswith redshifts

* Modest IR emitters at 0<z<0.5

* ULIRGs : quite rare at 0<z<1

* LIRGS: significant contribution at z>0.5

* More « normal » starbursts are not negligible neither

80% completeness limit

Rencontres de Moriond, March 6-12th 2005

60 μm luminosity Functions

Local IRAS LF

Rencontres de Moriond, March 6-12th 2005

(Local LF 60mic : Saunders et al. 1990, Takeuchi et al. 2003)

60 μm luminosity Functions

Rencontres de Moriond, March 6-12th 2005

(L,z)=*(z) [L/L*(z), z=0]

L*

*

* Evolution in luminosity :

L*(z) = L* (1+z) oL

* Evolution in density :

*(z) = * (1+z) o D

A « too strong » evolution in density overproduce the counts at the faint end

Additional constraints from the counts at faint fluxes (Chary et al. 2004, Papovich et al. 2004)

Evolution of the LF

Rencontres de Moriond, March 6-12th 2005

L D =

Papovich et al.

Simulations (z<1)

* exclude a pure evolution in density (Blain et al. 99. Xu et al. 00, Chary & Elbaz 01, ....)

Star formation history at z<1

LIRGs/ULIRGs dominate beyond z~0.7

Chary & Elbaz 2001

Blain et al. 2002

Lagache et al. 2004

. . . . . .

_ _ _ _ _

ULIRGs

total

L >10 L .11

IR

L <10 L .11

IR

Rencontres de Moriond, March 6-12th 2005

Compilation by Hopkins 2004

Star formation history at z<1

LIRGs/ULIRGs dominate beyond z~0.7

AGN contribution ??* ISO/XMM : <20% (Fadda et al. 2002)* X-ray +IR bkg synthetic models : <5% (e.g., Silva et al. 2004)

First Spitzer results : <15% of sources flagged as AGNs by VVDS& COMBO-17 (see also SWIRE, Franceschini et al. 2005)

Rencontres de Moriond, March 6-12th 2005

Star formation history at z<1

LIRGs/ULIRGs dominate beyond z~0.7

Contribution fromunobscured star

formation ??

* 60% understimate at z~0* 20-30% at z~1

Rencontres de Moriond, March 6-12th 2005

Stellar masses

IR-luminous sources are more massive than field optically-selected galaxies

IMF: Salpeter 55

COMBO-17

MIPS sourcesLIRGs

L >10 L .11.5

IR

Rencontres de Moriond, March 6-12th 2005

(see C.Xu ‘s review this morning)

Star formation history at z<1

LIRGs/ULIRGs dominate beyond z~0.7

Chary & Elbaz 2001

Blain et al. 2002

Lagache et al. 2004

. . . . . .

_ _ _ _ _

ULIRGs

total

L >10 L .11

IR

L <10 L .11

IR

Rencontres de Moriond, March 6-12th 2005

Compilation by Hopkins 2004

MIPS in the redshift desert

(Le Floc’h et al. 2004)

Rencontres de Moriond, March 6-12th 2005

* Balmer-break selection :(Adelberger et al. 2004)

* « GALEX drop-outs » : z>1

* IRAC color-color plots :3.6-4.5 versus 5.8-8.0

(IRAC photo-z technique)

Bimodal redshift distribution of the MIPS sources ?? Still debated(i.e., SSC results [D.Fadda yesterday] versus Perez-Gonzalez et al..........)

(C.Martin’s review yesterday)

* 55~65 % of 24μm sources at z<1 for flux>80μJy

Summary

* At 0<z<1, L* evolves at least by (1+z) ( exclude a pure density evolution)

3.5

* IR luminous galaxies start to dominate the SFRH at z>0.6

* LIRGs+ULIRGs = 70% of SFR at z=1

* Need a better understanding of IR SEDs : IRS GTO, MIPS SED mode...

Cornell University - Ithaca, December 1st 2004