8.7.2005Renzini Ringberg 20051 The cosmic star formation rate from the FDF and the Goods-S Fields R.P. Saglia – MPE reporting work of/with R. Bender, N

8.7.2005 Renzini Ringberg 2005 1

The cosmic star formation rate from the FDF and the Goods-S Fields

R.P. Saglia – MPEreporting work of/with R. Bender, N. Drory, G. Feulner,

A. Gabasch, U. Hopp, M. Pannella, M. Salvato

• Introduction • The Fors Deep and Goods-S Fields• Luminosity functions• Star Formation Rates and stellar densities (up to z=5)• Morphologies (up to z=1)• Conclusions

Gabasch et al. 2004, A&A, 421, 41; Drory et al. 2005, ApJL; 619, L131;Gabasch et al. 2004, ApJL, 616, L83; Pannella et al. 2005, ApJL, in prep


Introduction

Bouwens et al. 2004

“Madau plot”: Star Formation Rate history of the Universe

Open questions:

• Cosmic variance

• Galaxy selection

• Faint-end contribution

• Role of Dust

• Morphology splitHernquist & Springel 2003


The FDF and Goods-S fields

Heidt et al. 2003, A&A, 398, 49 Salvato et al. 2005, in prep

lim 26.8I lim 27.6B lim 25.4K U…K photometry, >7 times larger field than HDF


Photometric redshifts

Gabasch et al. 2004, A&A, 421, 41

362 spectra

SED template fittingBender et al. 2005

0.0

0.

56

028 1

zFOR

D

Sz

GOO s


Luminosity Functionsat 1500

Gabasch et al.2004, A&A,421, 41

Good agreementwith previous LFdown to the maglimit.= -1.07+-0.04 = -1.6 excludedat 2 level

A

z=0.6 z=1.3

z=2.5 z=4.5


Evolution of the LFs

*

*

slopes similar in UV and u' bands:

= 1.07 0.04,

decreases by 80-90%

1.6 excluded at 2 level

increases from 0.5 to

= 1.25 0.03 in ' and band

5

by

3.

s

1

M z z

mag

g B

Steidel et al. 1999


The UV-luminosity density and SFR

(no correction for dust)

Schechter Luminosity Function:

( ) exp

( ) (2 )tot

L LL

L L L

L L M dM L

28 1 31500 1.25 10 totSFR L M yr Mpc

The extrapolation to L=0 amounts to 2-20% for the FDFmagnitude limits!


The SFR in the FDF

Gabasch et al. 2004, ApJL 616, L83

No difference with I or B catalogues

Dust

Adelberger & Steidel 2000

0.3 difference

to 1.6 :

spectroscopic surveys are not de

dex

ep enough

0 2 4 6 0 2 4 6

Factor 5-9correction

At z>3 Bdrop-outs


The SFR in FDF and GOODS-S

*

Cosmic variance

less than

SFR(>L

)

No difference

for

Complete census

of galaxies

approache

0.

K lower by

0.2 dex

d

1dex

:

/ 3TOTS

L

FR

L


Stellar masses • Photoz + BC03

• 2 components (main+burst)

• Age, metallicity Dust, component ratio

Errors in log M/L:

0.1<d log M/L<0.2


Dust and SFRGALEXSchiminovich et al.

2005, ApJL 619, L47

SPITZEREgami et al. 2004

ApJS 154, 130

Stellar mass

Factor 2.5-3

• GALEX confirms SFR at z<1• SPITZER shows that ULIRG cannot dominate


MorphologiesAnalysis of HST ACS images:

FDF: 4 pointings, 1 orbit per pointing in the F814W filter 40 minutes exposures, I(AB, 10 sigma) = 26

Goods-S: 3/2.5/2.5/5 orbits in the BViz filters 100/80/80/160 minutes exposures BViz(AB, 10 sigma) = 27/27.2/26.5/26.5

Visual Classification performed by U. Hopp

Quantitative morphology performed by M. Pannella, fitting the 2D images with PSF convolved with the Gim2D and Galfit packages, I=24/24.5 for FDF (F814W) and Goods (F775W), z<1.15

Sersic Profiles


Quality Control

Mock catalogueof 4000 objectsfor each of the twofields, with

22.5<I(AB)<Ilim

0.05”<Re<2”

0.5<n<6

0<ellipticity<0.7


Visual Morphology

Final catalogue with 1647 objects, 90 sq. arcmin area, z<1.15, withMasses, redshifts, luminosities, dimensions, profiles


Mass completenessAt any redshift objectswith the highest M/L ratioare cut out of the samplebecause of the flux limit.

• SSP from BC03• formation at z=10• no dust• sub-solar metallicity• passively aging

Largest M/L lowest detectable M


Morphological stellar mass functionsThe mass at whichdisks becomes dominantis increasing with z

Disks dominate at all redshifts the lowmass end of the MF

In good agreement with Bundy et al.(2005) at the same zand Bell et al. (2003)at z=0

“MorphologicalDownsizing” ?


Stellar mass density evolutionThe total mass density atz=1 is 50% lower than at z=0

The morphological mixevolves dramatically withredshift

Mass density movesfrom disks to bulgesfrom z=1 to z=0

In agreement withBundy et al. 2005,Brinchmann & Ellis 2000


Two scenarios

Option 1: the 50% “missing stellar mass” at the high mass is provided by in situ star formation. The morphological mass density evolution from disks to bulges is driven by secular evolution.

Option 2: The star formation rate is not high enough to explain the missing stellar mass. Merging of (smaller mass) galaxies must play a key role. Merging of the massive disk systems explains the morphological evolution.


Specific star formation ratesOnly 2 objects would beable to double their massesto z=0 assuming constantSFR

Almost all the sample wouldbe unable to increase its original mass by more than30% with constant SFR in situ

Option 2 favoured


Conclusions: the SFR

• SFR estimates from B, I and I+B catalogues agree well and are confirmed by GALEX at z<1• SFR estimate from K catalogue is lower by 0.3 dex because it is missing galaxies with L<L* • Cosmic variance < 0.1 dex• Bright galaxies with L>L* produce 1/3 of the total SFR • Previous estimates of the SFR are too high by a factor of 2 because the faint-end slope of the LF has been overestimated• Dust correction is ~ factor 3• Complete census of galaxies nearly reached: SPITZER• The SFR is roughly constant up to z=4 and declines slowly beyond


Conclusions: Morphologies

• The morphological mix evolves strongly with redshift

• The stellar mass density moves from disks (at z=1) to bulges (at z=0)

• Merging must have an important role


The dust correctionUsing a factor 6.5 dust correction (or A28000=2):


The Sersic profile1/

( ) exp ( ) 1

1: exponen

n=0.5: Gaussi

4 : de Vaucouleu

an

a

r

ti

s

l

n

ee

n

rI r I k n

r

n

Documents

8.7.2005Renzini Ringberg 20051 The cosmic star formation rate from the FDF and the Goods-S Fields R.P. Saglia – MPE reporting work of/with R. Bender, N