The Cosmic Infrared Background

A N

ew V

iew on H

igh-Redshift Galaxy Form

ation

Bruno Guiderdoni

Institut d’Astrophysique de Paris

CNRS

2

Observation of IR/subm

m G

alaxiesand Cosm

ology ?•

The observation of the Cosmic IR Background is

necessary for the complete test of O

lbers’ paradox.•

The objects that contribute to the CIRB could bethe progenitors of local giant galaxies (test H

GF).

•The background due to dusty galaxies is aforeground for the observation of CM

Banisotropies.

•Early phenom

ena (e.g. the formation of Pop III

stars) are observed in the IR (redshifts z=10-30).

3

The Infrared View

on Galaxy Form

ationO

utline of the talk

•IR Starbursts

•The CIRB and dust heating : starbursts vs.A

GN

s•

Breaking the CIRB into sources : ISOPH

OT

(ISO), SCU

BA (JC!M

T), MA

MBO

(IRAM

)•

Forthcoming observational landscape :

SIRTF, PLAN

CK, H

ERSCHEL, A

LMA

4

How

dusty are forming galaxies ?

Young

stellarpopulation

WITH

OU

!TD

U!ST

WITH

DU

ST

From the STA

RDU

ST model (D

evriendt, Guiderdoni, &

Sadat, 1999)

5

Spectra of nearby galaxies : spirals and ULIRG

s

STARD

UST 1999

6

The IR luminosity sequence from

spirals to ULIRG

s

3.4 1012 L

sol

2.1 107 L

sol

STARD

UST 1999

7M

orphologies of UL

IRG

s (Surace et al. 1998)

8U

Surface Brightness versus r 1/4 (in kpc)

Surace &Sanders 2000

UL

IRG

s areprogenitorsof spheroids

exp.

r 1/4

9

The Cosmic

Infrared andO

pticalBackground

10

The Origin of the Cosm

ic IR/opticalBackground

•1996-1998 : discovery of the CIRB in FIRA

S data (Puget et al.1996, G

uiderdoni et al. 1997, Fixsen et al. 1998, Lagache et al.1998) and D

IRBE data (Schlegel et al. 1998, Hauser et al. 1998).

Strong evolution :10 x the no evolution prediction (IRAS lum

.funct.), tw

ice the COB. Interpolating/extrapolating gives

•(l>6 mm

)•

Thermal em

ission from dust : extinction is crucial in the

luminosity budget at high z, even if Z < Z

sun

•H

eating engine I: AG

N should contribute 10—

20 % (A

lmaini et

al. 1999)•

Heating engine II: starbursts should contribute 80—

90%

Ibol CIRB=

40¥10

-9Wm

-2sr-1

Ibol CO

B=

20¥

10-9W

m-2sr

-1

11

†

Ibol

=e

bol

4p

c dt4

(1+z)

Ú

Le fond diffus dépend de l’émissivité lum

ineusede l’univers ebol (W

/m3) intégrée sur la ligne de

visée

Effet cosmologique dû à

l’expansion de l’universL’intégrale est effectuéesur une durée de tem

psfinie: l’âge de l’univers

12

Black Hole G

rowth and the Cosm

ic Background

Ibol =c4p

hBH

˙ r BH c2

1+

zdt

=c4p

Ú0.1r

BH (0)c2

1+

zeff

Census of BH m

ass density from the local lum

inosity density :

rB (0)=

(9.0±1.4)10

7LBsun M

pc-3

1/3 from E ;

MLB

=6

Msun

LBsun

andM

BH=

0.005MM

agorrian et al. 1998

rBH (0)

=9

¥105M

sun Mpc

-3

Ibol =14

1+

zeff 10

-9Wm

-2sr-1

zeffª

2.5Ibol =

4¥

10-9W

m-2sr

-1

13

Stellar Nucleosynthesis and the Cosm

ic Background

Ibol =c4p

DYDZh

Y+

hZ

Ê Ë ˆ ¯

˙ r Z c2

1+

zÚ

dt=

c4p0.03r

Z (0)c2

1+

zeff

Census of local metal density from

the local luminosity density :

rB (0)=

(9.0±1.4)10

7LBsun M

pc-3

2/3 from Sp ;

MLB

=2

Msun

LBsun

andZ

ª0.02

1/3 from E ;

MLB

=6

Msun

LBsun

andZ

ª0.03

+0.02for m

etals in IGM

(Mushotzky &

Loewenstein 1997)

MZ

LB

=0.3

Msun

LBsun

rZ (0)=

1.1¥10

7Msun M

pc-3

Ibol =50

1+

zeff 10

-9Wm

-2sr-1

zeffª

1.5Ibol =

20¥10

-9Wm

-2sr-1

14

The Cosmic Star Form

ation History

Deconvolved

CIRB

Uncorrected

LBGs

LBGs

corrected fordust

SAM

SCUBA

sources

15

Resolution of the CIRB into point sources

•ISO

/ISOCA

M (15 mm

) : 70 % @

Sn >30 mJy

•ISO

/ISOPH

OT (175 mm

) : 5 % @

Sn >200 m

Jy–

About 200 sources (Puget et al. 1999, D

ole et al. 2000)•

JCMT/SCU

BA (850 mm

) : 40 % @

Sn >2 m

Jy–

About 100 sources (Sm

ail et al. 1997, Hughes et al.

1998, Eales et al. 1998, etc.)•

IRAM

/MA

MBO

(1300 mm) : 30 %

@ S

n >2 mJy

–36 sources (Carilli et al. 2000, Bertoldi et al. 2000)

16G

ispert et al. 2000

17

From Faint C

ounts to the Diffuse B

ackground

†

In=

Sn

0 •ÚdNdS

n

dSn

†

sn

=S

n2

0 •ÚdNdS

n

dSn

W

Ê Ë Á ˆ ¯ ˜ 1/2

†

Sconf

=s

n≡

Sn

2

0

3Sconf

ÚdNdS

n

dSn W

Ê Ë Á Á

ˆ ¯ ˜ ˜ 1/2

In Jy sr -1 or W m

-2 Hz

-1 sr -1

Diffuse background

Fluctuations in solid angle W

Confusion lim

it in solid angle W

In Jy sr -1 or W m

-2 Hz

-1 sr -1

In Jy or W m

-2 Hz

-1

18

The FIRBACK

ISOPH

OT

Deep Survey at 175 mm

3.89 deg2 in 3 fields (2

North, 1 South); 196

galaxies with S

n >135m

Jy ; counts showstrong evolution

Marano S field

N 2 field

N 1 field

19

Detection of CIRB fluctuations in the FIRBA

CK survey

Lagache & Puget 2000

Data in the M

arano 1 field

Cirrus confusion noise

Cirrus confusion noise xfootprint pow

er spectrum

P(k)µk

-3

20

The «"negative K-correction"» at subm

m/m

m w

avelengths

Guiderdoni et al. 1998

850 mm

4 mJy

The600—

2000mm

fluxdirectlym

easuresL

IRprovidedz>0.5

W0 =1, h=0.5

21

The Hubble D

eep Field observed by SCUBA

at 850 mm

8.7 arcmin

2

s=0.45 mJy

FWH

M=14.7

arcsec

22

z=3.4

z=3.8

z=0.9

z=2.0

z=3.2 ?

ID of SCU

BAsources: optical

This is theactual opticalID

(lensed)

logLIR =11.9

logLIR =11.8

logLIR =11.8

logLIR =11.6

23

ID of SCU

BA sources : radio continuum

Smail et al. 2000

SCUBA

error box

VLA

1.4 GH

z contours

Radio/submm

«"photometric"»

redshifts (Carilli & Y

un 1999)give <z> > 2

24

ID of IR/subm

m sources

•ISO

CAM

@ 15 mm

, Sn >30 mJy : ID

z = 0.5-1 (~ dusty,lum

inous galaxies of the CFRS)•

ISOPH

OT @

175 mm, S

n >200 mJy : ID

z < 0.5, + some

sources à z ~1 ? (FIRBACK

)•

SCUBA

@ 850 mm

, Sn >2 m

Jy : 1 source arcmin

-2, IDs are

diffficult; many «"blank fields"»; m

ajority of source IDs at

1<z<4–

some A

GN

s (10 % of CIRB ?)

–som

e EROs (10 %

du C!IRB ?)–

LIR lum

inosities : a few 10

11 to a few 10

12 L § provided z>1

–r

SFR (z>1) = 10-1 M

§ yr -1Mpc -3 (H

ughes et al. 1998)

25

No connection

between the

SCUBA

andChandra sources atS

850mm >2 m

Jy &F

0.5—2keV >1—

3 10-15

erg cm-2 s -1

Fabian et al. 2000,Severgnini et al.2000

Chandra sources

Most natural

interpretation :SCU

BAsources arepow

ered bystarbursts

26

HR

10, z=1.44

Ic -K=5.8

LIR =7 10

12 h50 -2 L

sun

Dey et al. 1999

27

The Cosmological Interest of

SCUBA

sources•

Local LIRGs and U

LIRGs are pow

ered bystarbursts (and A

GN

s for the most lum

inousobjects, Lutz et al. 1998) triggered by interactionand m

erging. They are thought to be theprogenitors of E galaxies.

•If SCU

BA high z LIRGs and U

LIRGs are m

ergers(very little direct observational evidence so far),w

e are seeing the crucial step of hierarchicalgalaxy form

ation

28

Predicted IR/submm

counts with sim

ple SAMFit subm

mcounts w

ithad hocextinguishedstarbursts

Devriendt &

Guiderdoni 2000

29

Predicted COB+CIRB w

ith simple SA

M

Devriendt &

Guiderdoni 2000

30

Predicted z distribution with sim

ple SAM

Devriendt &

Guiderdoni 2000

31

32

33

34

Forthcoming IR/subm

m O

bservationsA golden era for high-z subm

m sources

•SIR

TF (launch in 2003) : MIPS (24, 70, 170 mm

) : rest-frame M

IR for z<3.•

HER

SCH

EL (launch in 2007) : PACS (60-90, 90-130, 130-210 mm

) andSPIRE (200-350, 350-450, 450-670 mm

)–

Deep fields (S

lim =15 mJy @

350 mm) : a few

104 sources. Expected 1<z<3.

Confusion limited

–W

ill study the SEDs of a large sam

ple of high-z ULIRG

s•

PLAN

CK

(launch in 2007) : HFI (350, 550, 850 mm

, 1.3, 2 mm

)–

All-sky Com

pact Source Catalogue (Slim =260 m

Jy @ 350 mm

) : a few 10

4 to 105

sources. Expected <z>=0.2.Confusion limited

–W

ill study the rarest/most lum

inous ULIRG

s•

ALM

A (full operation 2010) : (850 mm

, 1.3, 2 mm

)–

5s = 30" mJy/beam in texp =1h. W

ith 0.1 arcsec resolution : ID, m

orphology–

Spectroscopic measures of z w

ith CO lines

–W

ill follow-up blank fields and optically selected high-z sources (LBGs)