SWIRE Science: Investigating the Active and Passive Universe on Large Scales Alberto Franceschini Padova University

"SWIRE Science Team Meeting"

IPAC, December 17-19, 2001

The SWIRE view on the Active Universe: AGN Contribution to the Infrared and X-ray Backgrounds [weighing the stellar vs. gravitational energy budget]

Summary

• The CIRB, recent results, comparison with XRB • Ultimate energy sources for the BKGs: stellar emission and gravitational energy • Physical properties of the CIRB sources: AGN vs. SB • The X-ray diagnostics: deep IR/X-ray surveys • Testing the origin of the XRB • Prospects for SWIRE

The Global Background Radiation

COBE

Discovery of the Cosmic Infrared Background (CIRB) (Puget et al. 1996; Hauser et al. 1998) λ=100 μ

COBE  (IR)=40 nW/m  sr HST  (opt)=17 nW/m  sr The Infrared and Optical Background Radiations

ULTIMATE ENERGY SOURCES

XRB => mostly gravitational CIRB => mostly stellar?

A solid limit: mass in local Massive Dark Objects (MDO's): M MDO ~ 2 10 -3 M * (M * : mass in spheroids Kormendy & Richstone ) How much energy out of this? η stellar ~10 -3 , ε AGN ~0.5 ( limit) L AGN ~ 2 10 -3 ε/η L star ~ L star However : η stellar ~ (1-5) 10 -3 , ε AGN ~ (0.1-0.5) , M MDO ~ (2-5) 10 -3 M * (Magorrian et al.)

A) 99% of the gravitational energy might be undetectable in X-rays because absorbed and re-radiated in the IR ~50% or more of the CIRB might be due to AGNs Relevant for the history of stellar formation (SF) B) XRB peak at 30 keV Compton-thick emission, implies that the 1-10 keV range covered by CHANDRA & XMM might not be appropriate at all to sample accretion processes Long-λ background critical for rather fundamental issues of • • cosmology: history of barion transformations in stars AGN unification, obscured quasar populations

Similarities of the CIRB/OPT. spectral shape and the typical StarBurst spectrum M82 broad-band spectrum Log  L(  ) (erg/s) Log(  ) [  ]

SCUBA

850  survey of the CFRS 1415h field (Eales et al. 2000) 6.9x6.4 arcmin 19 sources above 3.5 mJy

2 1.5

1 0.5

LW3 z=0

Typical source spectra

LW3 15 

K-corrections

LW2 6.7 

(Fadda et al. 2000)

Contribution of faint ISO sources to the diffuse mid-IR background light 15  differential counts (Euclidean normalized) by Elbaz et al. (1999)

2 arcmin HDF-North image overlayed by the ISOCAM LW3 15  contours by Aussel et al. 1999

2.7 arcmin ISOCAM 15 μ image overlayed to the FORS2/VLT R-band image on the FIRBACK UDS field

IR-starbursts UV-optical galaxies Optical & X-ray AGNs

Evolution of the comoving luminosity density

(Franceschini et al. 2001)

Correlations of the MIR and FIR fluxes => the global IR spectrum (Elbaz et al. 2001)

Bolometric luminosities of the faint ISO sources

=> only 30% are ULIRGs (L bol >10 12 L o )

The faint sources detected by ISO at 15  are responsible for the bulk of the CIRB background

ISO : tentative way to resolve the CIRB

• Appropriate z (z ~ 1) • Easyly identified sources • Good sampling of the part of the LF making the CIRB • Large samples available • Well-known z-distributions

First characterization of the CIRB sources

LOW-RESOLUTION ISAAC OBSERVATIONS OF Ha+NII (Rigopoulou et al. 2000)

To summarize: •18 galaxies observed with H=19-22.5

•H  detected in 15 (low-res) •SFR(H  ) = 10 M/yr •SFR(FIR) = 100 M/yr

HST I-band image HDF- South source 27 M=3 10 12 M o (H o = 60 Km/s) d=36 kpc

X-ray, IR and optical diagnosis of AGN vs. Starburst emission (Bassani et al. 2000)

X-ray vs. mm vs. optical (maps of A1835 and A2390) X-ray: CHANDRA optical: I-band mm: SCUBA 850  scale: 10 arcsec CHANDRA SCUBA CHANDRA SCUBA (Fabian et al. 2000)

Severgnini et al. (2000) => Sub-mm and X-ray emissions as two unrelated penomena

Modelling the IR SEDs of AGNs

Radiative transfer modelling

IR spectra of a typical AGN (NGC 1068) with those of typical starbursts (M82, Arp220, Arp 244) and a mixed AGN/SB (NGC 6240) Elbaz et al. (2002)

NGC 1068 [Floch et al. 2001] [ISO CVF]

Entirely different spectral shapes for galaxies and Active Galactic Nuclei in the Mid-Infrared

Granato, Danese, Franceschini (1997) IR SEDs of Active Galactic Nuclei Models based on radiative transfer solutions

M82 IR spectrum fitted by AGN model

Image at 15 μ by ISO of the Lockman Hole (Fadda et al. (2001) Large square: shallow survey (0.7x0.7 deg.), small square: deep survey (20x20 arcmin) Inset: overlay of ISO and XMM (circle) on an I image

The problem of the origin of the flux: starburst or AGN ?

CHANDRA observation of the Hubble Deep Field North Brandt et al. (2001) (see Mushotzky et al. 2000, Hornschemeier et al. 2000 ) S 0.5-2 >5 10 -17 (erg/cm 2 /s)

ISO & CHANDRA sources in the HDFN (Fadda et al. 2001)

Cross-correlation between ISO and CHANDRA in the HDFN

A JOINT ISO/XMM Deep Investigation in the Lockman Hole

XMM image by Hasinger et al. (2001) ISO image by Fadda et al. (2001)

IR and X-ray dapths in the Lockman and HDFN

STATISTICS ON ISO/XMM SOURCES IN THE LOCKMAN HOLE

X-ray vs. IR flux diagnostics

High X-ray luminosities =>>> they are type-II QSO

X-ray to IR spectral index as a function of the X-ray flux

AGN contribution to the CIRB: the ISO guess (<20%)

Contribution of ISO galaxies to the CIRB

C CIRB 140 = 25(+/-7) W/m 2 /sr at λ= 140 μ IGL 15 : contribution to CIRB in W/m 2 /sr at λ= 15 μ IGL 140 : contribution to CIRB in W/m 2 /sr at λ=140 μ

R:

ratio of νS ν at 140 and 15 μ

New AGN statistics based on the mid-IR selection

• Assuming that unclassified X-ray sources are type-2 (supported by these data): – 7 AGN type-1 – 12 AGN type-2

ISO & XMM sources in common in the Lockman Hole area: type-II QSO originating the XRB Franceschini et al. (2001)

X-ray hardness ratio vs. optical color X-ray luminosity vs. optical color

Hardness-ratio HR=[H-S]/H+S] HR3: H=4.5-10, S=2-4.5 keV HR2: H=2-4.5, S= 0.5-2 keV

Tests of the XRB synthesis model: a) bolometric luminosities of type-I vs. type-II objs.

b) fractions of type-I vs. type-II

X-ray emissivity properties of faint ISO sources => 10% of sources show "AGN-type" X-ray activity

ISO sources IR-selected AGNs Where do the IR-selected AGNs contribute to the XRB? (cnt.)

The SIRTF "SWIRE" Survey

SIRTF Wide-area IR Extragalactic Survey, Legacy Programme (C. Lonsdale and 18 co-investigators) ~ 70 square degree using all SIRTF photometric bands

Table A-2: Expected SWIRE Performance: Noise and Sensitivity Estimates

Wavelength Cirrus noise,1



# Extragalac tic * (1 MJy/sr at 100



m) 300 nJy 2.0



Jy Confusion noise, 1



150 nJy 1



Jy 85



Jy SWIRE photometric sensitivity, 1



1.4



Jy 1.9



Jy 5.5



Jy 6.5



Jy Franceschini model confusion distribution

Starbursts AGN

A new AGN/Starburst diagnostic tool: the ISO LW3(15μ)/LW2(6.7μ) flux ratio

SWIRE Survey Fields Target RA Dec



100μ BKG E(B-V) Area

(sq.deg.) ------------------------------------------------------------------------------------- XMM-LSS Chandra-S 02 26 -04 30 -18 03 45 -30 -48 1.1

< 0.4

0.35

0.12

10 5 Lockman Hole 10 40 Lonsdale Hole 15 10 ELAIS S1 ELAIS N1 ELAIS N2 00 35 -43 28 -43 16 09 56 27 +74 16 37 57 56 +44 +68 41 16 +62 < 0.4

< 0.4

< 0.4

< 0.4

< 0.4

0.10

0.20

0.12

0.10

0.11

15 10 15 10 5 --------------------------------------------------------------------------------------

CONCLUSIONS

• The CIRB background contains essential information not only on the history of SF , but also on the hystory of gas accretion, including obscured QSO phases • Most of the XRB and CIRB now resolved into sources => combined X/IR info • No clear-cut diagnostics for AGN/SB discrimination, two phenomena intimately connected and concomitant • Only combined multi-λ approach may give answer with some confidence • Preliminarly: XRB : gravitational energy CIRB : mostly stellar energy • SWIRE : essential contribution to the investigation of hidden phases of gravitational accretion, by exploiting the large survey area, which is essential to detect substantial samples of type-II AGNs [NB: our ISO/XMM survey in Lockman detected only 14 type-II's over 220 sq.arcmin]