A Bolometric Approach To Galaxy A Bolometric Approach To Galaxy And AGN Evolution.And AGN Evolution.

L. L. Cowie

Venice 2006

(primarily from Wang, Cowie and Barger 2006, Cowie and Barger 2006 an

d Wang 2006 thesis)

The Hawaii bolometric sample:

To understand the star formation and accretion history we need a census of all energy-producing galaxies & supermassive black holes in the universe, including those obscured by gas & dust.

Best to choose them by their bolometric light rather than at a single frequency.

• The HDF /GOODS-N /CDF-N

is still the best field for this!

Wide Hawaii HDF-N DataWide Hawaii HDF-N DataBand Sensitivity Limit Telescope / Camera Source

(5sig Jy)

U 0.052 KPNO 4m Capak et al. (2004)

B 0.063 Subaru / SuprimeCam Capak et al. (2004)

V 0.069 Subaru / SuprimeCam Capak et al. (2004)

R 0.083 Subaru / SuprimeCam Capak et al. (2004)

I 0.209 Subaru / SuprimeCam Capak et al. (2004)

z’ 0.251 Subaru / SuprimeCam Capak et al. (2004)

J 0.839 UH2.2m / ULBCAM Trouille et al. (2006) (400 sq arcmin)

H 1.06 UH2.2m / ULBCAM Trouille et al. (2006)

3.6 m 0.327 Spitzer / IRAC GOODS Spitzer Legacy Program

4.5 m 0.411 Spitzer / IRAC GOODS Spitzer Legacy Program

5.8 m 2.27 Spitzer / IRAC GOODS Spitzer Legacy Program

8.0 m 2.15 Spitzer / IRAC GOODS Spitzer Legacy Program

24 m 80 Spitzer / MIPS GOODS Spitzer Legacy Program

Just under 4000 galaxies have been spectroscopically identified in the region: remainder can be assigned photometric redshifts. J and H data considerably improves the robustness at z>2.

Spectroscopicredshifts (as ofearly 2006)

503 X-ray sources:(purple crosses) 202 20cm Radio sources (red squares): rectangle is core GOODS region.

HAWAII BOLOMETRIC SAMPLE:

2740 objects with 0.3-24 micron fluxes above 1.5x10^(-14) erg cm^(-2) s^(-1) in the 140 square arcminute core GOODS region.

This already contains all but 5 of the 40 microJy radio sources and all but 3 of the X-ray sources (CDF-N). We add the remaining 7 sources (2 are overlapped).

Goal is a near-complete spectrosopic identification of the sample: with a uniform 4000-10000A spectral database (DEIMOS spectrograph) of very high quality and spectral resolution.

Sample contains all of the 24 micron sources (this determines the limiting flux).

STATUS:

Goal is a complete spectrosopic identificationof the sample: currently 1890/2475 of the sources are spectroscopically identified and all but about 100 of these have high quality spectra.

Red=X-ray AGN

Redshift distribution of Z band sources

• Today I just want to focus on the

analysis of the submillimeter light

and its implications for the star formation

SCUBA Survey in the GOODS HDF-NGOODS HDF-NGOODS HDF-N~110 arcmin2 by SCUBA0.4-4 mJy (rms) sensitivity

~ 95 hours integration 27 sources at >3.5

Wang, Cowie, & Barger (2004)

HDF-proper

SCUBA 850m map

HST ACS imaging

Spectroscopy of 20cm Selected Submm SourcesSpectroscopy of 20cm Selected Submm Sources

redshift desert radio sensitivity limit

Chapman et al. (2005)18 Keck nights~ 100 submm sources observed~ 70 identified

median redshift = 2.22.2

Problems

• Submm sources that are above SCUBA’s detection limit (~2 mJy) only contribute ~20% of the total submm background.

• Only 60% of the above 20% can be detected by radio telescopes to 40 microJy at 20cm.

• Chapman’s radio selected submm sources only represent ~10% of the total background.

• Need to know about the faint (<2mJy) sources.Need to know about the faint (<2mJy) sources.

Cowie, Barger, Kneib 2002

Broken power law fit

EBL convergent fit

Weakly divergent

“Typical” source about 0.7mJy

Stacking Stacking AnalysisAnalysis

850 m Stacking Analyses

Band N <S850> I

(mJy) (Jy Deg-2)

ULB 1.6 m 3094 0.20 0.03 18.3 2.4

IRAC 3.6 m 5245 0.11 0.0066 19.6 3.4

MIPS 24 m 493 0.66 0.06 11.4 1.1

VLA 20 cm 101 1.31 0.13 4.0 0.40

1.6 m + 3.6 m 1783 24.0 2.0

total 850 um EBL : 31-44 Jy deg-2 (COBE)

Submm EBL vs Spectral Type

Sb Sc

Sd Irr

E?

Intrinsically Red Intrinsically Blue

Submm EBL vs RedshiftSubmm EBL vs Redshift

core Near-IR sample

Chapman et al. (2005)

Compute star formation rates from measured 20cm fluxes of all the sources contributing to the submillimeter light (the core sample).

Compute average radio power of the sample in each redshift interval.

Assumes FIR-radio correlation but avoids assumptions about dust temperature.

STAR FORMATION HISTORY:

Cosmic Star Formation HistoryCosmic Star Formation History

Cosmic Star Formation History (txMdot)Cosmic Star Formation History (txMdot)

UV

Submm/20cm

since Big Bang

Mdot times t Integrated star density

All of the backgrounds (including850 micron) have strong contributions from below z=1.

However the UV and the 850 micron comefrom different galaxy populations.

UV

[OII]

850850micron

20 cm

SummarySummary

• We detect most (60%-80%) of the submm EBL using the near-IR population.

• Most of the submm EBL comes from intermediate type galaxies at

z ~ 1. (Not the same sources that dominate the UV)

• Star formation history peaks at z ~ 1 and is flat at z > 1.

• Wang, Cowie and Barger, 2006 astro-ph/512347 (ApJ upcoming)

• The bolometric sample will appear shortly in Cowie and Barger (2006)

Number Counts from ClustersNumber Counts from Clusters

0.3-2 mJy : N(>S) = 3.5103 (S850/2 mJy)-1.2 deg-2

= 20 (+32/-8) Jy deg-2

Cowie, Barger, & Kneib (2002)

SuprimeCamSuprimeCam0.45°0.45 °

Capak et al. (2004)

HDF-proper

Spitzer ImagesSpitzer ImagesGOODS Spitzer Legacy Program

20’ 13’Confusion limited at 3.6-4.5 m

Extragalactic Background Light

total 850 um EBL : 31-44 Jy deg-2

AGN in the Z band sample

Submm EBL vs Near-IR ColorSubmm EBL vs Near-IR Color

B<24 subsample: