Evolution of the comoving infrared energy density up to z~1 * Emeric Le Floch, 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 24μm Rencontres de Moriond, March 6-12th Chary et al Gruppioni et al Lagache et al 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 MIPS sources * 465 with spec z * 2170 with phot z (total 2635 with redshift) MIPS 24μm 775 arcmin 2 Le Fèvre et al. Vanzella et al. Szokoly et al. Wolf et al.

R-band mag versus Rencontres de Moriond, March 6-12th % 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 source histograms 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: < 0.04 for R<22mag < 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 MIPS Redshift CDFS Total COMBO-17 (3 fields 30x30) B-band lumin. density R<25.5 M <-16 B

Rencontres de Moriond, March 6-12th 2005 Cumulative counts ~85% identified with R<25.5 optical counterparts averaged over 5 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.

Wavelength F. LIRGs ULIRGs F = 0.3mJy F = 0.08mJy 24μm Rencontres de Moriond, March 6-12th μm IR luminosity ?

IR luminosities in the CDFS 2635 sources with 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*L* * * Evolution in luminosity : L*(z) = L* (1+z) o L * 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 Lagache et al _ _ _ _ _ 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 from unobscured 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 sources LIRGs L >10 L 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 Lagache et al _ _ _ _ _ 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 Floch 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 : versus (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.Martins 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