GOODS-Herschel: an IR main sequence for star forming galaxies ! from the Main Sequence to starbursts and obscured AGNs
David Elbaz , CEA Saclay Mark Dickinson, Emanuele Daddi Ho Seong Hwang, Georgios Magdis, Maurilio Pannella Tanio Diaz-Santos, Benjamin Magnelli & GOODS – Herschel team GOODS-Herschel: an IR main sequence for star forming galaxies ! from the Main Sequence to starbursts and obscured AGNs
• There are many reasons to believe that the physics of galaxy/star formation is a complex process involving turbulence, multiphase physics, magnetic fields, shocks... mergers, environment effects, positive/negative feedback/AGN
% of stars formed ~ % Universe age !
~ 25% of present-day stars formed @z>2
Le Borgne, Elbaz, Ocvirk, Pichon 10 GOODS-Herschel: an IR main sequence for star forming galaxies ! from the Main Sequence to starbursts and obscured AGNs
• There are many reasons to believe that the physics of galaxy/star formation is a complex process involving turbulence, multiphase physics, magnetic fields, shocks... mergers, environment effects, positive/negative feedback/AGN • Morphological studies have globally failed. Merger rate ? Progenitors of Sp/E ?
?
z=0 z=1.5 (-10 Gyr) Scaling laws for early-types ...
• Early-types follow some simple scaling laws (fundamental plane) => common history of star formation • Star formation appears to have taken place in short timescales in these systems • Most present-day stars are locked in such systems. SNIa: O-> Si28-> Ni56-> Co56-> Fe56
Thomas +05 Scaling laws for late-types ...
• Schmidt-Kennicutt relation : projected SFR surface density ~ gas surface density ! puzzling that it extrapolates to the population of mergers such as (U)LIRGs
Why is the SK slope >1 ? Slope 1.4 => SF efficiency larger in (U)LIRGs
Schmidt-Kennicutt relation Kennicutt 1998
>3x104 cm-3 for HCN -3 >500 cm CO (H2) Gao & Solomon (2004) Scaling laws for late-types ... a unique SK law or 2 modes of SF ?
Daddi +10, Genzel +10
!CO=M(H2)/LCO !CO=0.8 for !CO=4.5 for mergers/ULIRGs mergers/ULIRGs
!=4.5 for normal Sp !=4.5 for normal Sp
Conversion factor: same !CO for all galaxies in Kennicutt (1998)
!CO / 6 for (U)LIRGs (Downes & Solomon 98, Solomon & Vanden Bout 05) Bouché +07 => slope= 1.7 ! 1.4 Steeper slope or 2 modes of star formation ? Scaling laws for late-types ... a unique SK law or 2 modes of SF ?
-1 Large % of massive (K-sel.) z=1.5-2.5 galaxies (BzK) harbour high SFR (few 10-100 M"yr ) ! high duty cycle ~40%, SF lasting ~0.5—1 Gyr ! large gas reservoirs ?
If long lasting SF ! not merging powered ULIRGs ! ! gas properties, conversion factors ?
High-z CO SEDs : warm gas, brightest CO fluxes are transitions J 5 to 7 ~ M82 nucleus. High gas densities, merger (?) ! require knowledge of several transitions to determine the correction factor...
! =M /L = 4.6 M (K km s-1pc2)-1 for Milky-Way CO gas CO " If !CO is spiral-like in massive z=1.5 (Solomon & Barrett 1991) galaxies => extremely gas rich -1 2 -1 !CO=Mgas/LCO= 0.8 M" (K km s pc ) for ULIRGs 1) gas mass ~1-2x1011 M of H (Downes & Solomon 1998) " 2 2) gas fractions ~60% or more
Dannerbauer, Weiss et al 2007 Daddi +09, +11
IRAM PdBI D-conf IRAM PdBI B-conf (0.87 mm, 345.8 GHz) (1.3 mm, 230.5 GHz)
VLA Bconf (2.6 mm, 115.3 GHz) Scaling laws for late-types ... a unique SK law or 2 modes of SF ?
Ivison +11
Daddi, Elbaz +10 Normal galaxies detected in CO (Daddi +08,10, Dannerbauer +09, Aravena +10; Tacconi +10; Genzel +10; Salmi +11)
Dannerbauer +11 Discovery of luminous IR galaxies, >90% of light in IR IRAS : 57 cm Dominate the bright-end of the luminosity function Mostly major mergers…
Space density of LIRGs x70 at z~1 ISO : 60 cm They dominate the SFR density at z>0.7 Extrapolation to far IR ! bulk of the IR background / LIRGs
Spitzer : 85 cm
Herschel: 350 cm
At z=0 ! ~2 IRAS : 57 cm Discovery of luminous IR galaxies, >90% of light in IR Dominate the bright-end of the luminosity function Mostly major mergers…
Space density of LIRGs x70 at z~1 ISO : 60 cm They dominate the SFR density at z>0.7 Extrapolation to far IR ! bulk of the IR background / LIRGs
• Stacking in far IR ! resolve peak IR bkg • Increasing density LIRGs/ULIRGs up to z~2 Spitzer : 85 cm v • Large Sp fraction among z~1 LIRGs • signature of Compton Thick AGN @z~2
Compilation by Hopkins 2004 total!
11 LIR <10 L"!
11 LIR >10 L"! ULIRGs!
Le Floc'h +05! problems with extrapolations from both sides of the peakPapovich IR +07, SED Daddi +07
obscured AGNs Compton thin unobscured AGNs
Compton Thick AGNs
• MIR-excess & stacking (Daddi +07, Papovich +07, Magnelli +09, Murphy +09, Fadda +10, Yan +05) : larger PAH emission or AGN ? • AGN contribution to MIR: CXB unresolved (Gilli +07,...) • SMGs ! different IR SEDs: colder Tdust + larger PAH EW (Pope +08,...) • Distant galaxies are less metal rich !less dust, ! PAH ? (Madden +05, Engelbracht +05) !"#$%&'()*'+%#,"-.'/'0*'(12#'
-1 >200M!yr -1 >20M!yr
-1 >1500M!yr
Stacking @70um CE01 + counts
Magnelli, Elbaz + 10 Le Borgne, Elbaz +09
• cosmic SFR density peaks at z~1 or 2 ?
• do ULIRGs dominate the CSFR at z~2 ?
• until now, bolometric luminosity extrapolated from mid-IR or sub-mm
! GOODS - Herschel Herschel • 57% of the Herschel routine mission science time is dedicated to Key Programmes (11257.7 hours) : – 52% of Guaranteed Time KP (5878.9 hours)= 93% of all GT – 48% of Open Time KP (5378.8 hours)= 40% of all OT • 22% of all KP time for extragalactic surveys : – 26% of all GT KP (1555h, 62% of extragal.surveys) : • HERMES (SPIRE GT, 900h) coordinated by S.Oliver & J.Bock • PEP (PACS GT, 654.9h) coordinated by D.Lutz – 18% of all OT KP (962.6h) , 62% of extragal.surveys : • ATLAS (PI S.Eales, 600h) • GOODS-Herschel (PI D.Elbaz, 362.6h) GOODS-Herschel (Herschel Open Time Key Program)" The Great Observatories Origins Deep Survey : far infrared imaging with Herschel
Collaborators (60): Fr, US, G, UK, Gr, It, Can, ESO, ESA
362.6 hours (100µm & 160µm PACS + 31h SPIRE)
1. to resolve most of the cosmic SFR density up to z ~ 4, by detecting ~ 2000 galaxies in the unexplored regimes of normal galaxies up to z ~ 1, LIRGs up to z~ 2, ULIRGs to z~4 2. to bridge IR and UV selected galaxies down to the level where both SFR agree up to z ~ 1.5 and potentially up to z ~ 4 as discussed below. 3. to identify and study the buried Compton Thick AGNs responsible for the still unresolved 30% fraction of the cosmic X-ray background (CXB), which peaks at 30 keV. X UV U B V I Z J H K 3.6µm 4.5µm 5.8µm 8µm IRS16 MIPS24 radio 2x10-16erg/s/cm2 ~28AB 22AB ~1µJy 50µJy 20µJy 12µJy
Herschel extragalactic surveys" GOODS-Herschel OT KP
Wilson 07 ESO-report
COBE (NASA) GOODS-North 100/160/250 µm
GOODS-South 24/100/160µm
240 µm (COBE/DIRBE, NASA) 3442(567-#&+78'9-":7#',+7';8<$=,7'>79,+#'-7=&+=:87':.'67-#&+78'?'' @A'$B.CADD;$E'@FGH'$B.CAHD;$E'I$B.CFID;$E'J$B.CKID;$E'AD$B.CIDD;$'' !"#$%&'()*+,%',-+,#('./-'012345'
MIR remains crucial
1468 galaxies 70% complete in spec z ~30% in phot z Deep far infrared images with a 3.5 m telescope:! challenging the confusion limit *",$%& !"#$%& '($%&
)*$%& +#*$%&+#*$%&
6.5'
7.5' The power of multi-wavelength imaging against confusion -**$%&!-*$%&'-*$%& +#*$%&+**$%&'($%&!"#$%&*",$%&
7.5' x 6.5' zoom on the GOODS-North field (10' x 15')
HGIN'
LGI'=-&$%M' HST Spitzer Herschel PACS & SPIRE VLA
FWHM=6.7" 11" 18.1" 24.9" 36.9" F#$ 1.5' boxes
160µm 250250mµm 350µm zz == 0.94711.5230 µ 500µm L = 2.6 x 1012 L from far-IR 160µm IR " 70µm 100µm 350µm 100µm vs 70µm 12 LIR= 3.5 x 10 L""from 24um"
24µm 24µm modified blackbody, "=1.5 modified! Tdust blackbody, "=1.5 ! Tdust
Hwang +10 %(µm)$ !"#$"%&'&()#*'$"#+(,-(".(#%/'&#%/&2$"3#3'4'5$(0#
starbursts
Stellar mass MIR-FIR correlation (Chary & Elbaz 01, Elbaz et al 02)
IR vs ISOCAM 15 µm IR vs IRAS 12 µm
IR vs ISOCAM 6.75 µm
Chary & Elbaz 01 David Elbaz Latest news from deep infrared surveys 23 Before Herschel total IR luminosities were extrapolated from the mid-IR & submm
L(IR) vs L(15 µm) L(IR) vs L(12 µm) 15 µm vs IR
L(IR) vs L(6.75 µm) K correction The mid-IR excess problem... SED evolution/AGN/k-correction ?...
• mir and far IR consistent with local SEDs (Chary & Elbaz 01) up to z~1.5 (blue, green dots)
• at z>1.5: "mid-IR excess" (Daddi +07, Papovich +07) (orange, red dots)
24µm Elbaz, Hwang +10, 11 GOODS-Herschel (Elbaz, Hwang +11) The mid-IR excess problem... SED evolution/AGN/k-correction ?... 0*'$=%M'#7O;7M&7'?'F'$">7#'"P'#,=-'P"-$=<"M'Q' 6&$3$"#/%#17(#18/#01'&#%/&2'9/"#2/)(0#:# 17(#&/4(#/%#01'&#%/&2'9/"#./2;'.1"(00<<<#2(&3(&0<<<' 0*'$=%M'#7O;7M&7'?',+7'-"87'"P'()'&"$9=&,M7##' 0*'$=%M'#7O;7M&7'?',+7'-"87'"P'()'&"$9=&,M7##' 0*'$=%M'#7O;7M&7'?',+7'-"87'"P'()'&"$9=&,M7##' 0*'$=%M'#7O;7M&7'?',+7'-"87'"P'()'&"$9=&,M7##' 6&$3$"#/%#17(#18/#01'&#%/&2'9/"#2/)(0#:# 17(#&/4(#/%#01'&=-&010<<<' Definition of a "starburst"
t(gas consumption)= Mgas / SFR = 1 / SFE (SF efficiency) Definition #1: t(gas consumption) << t(Hubble) => starburst
• The Antennae: (LIRG) 11 -1 LIR=1.1x10 L! ! SFR= 19 M!yr 9 M(H2)=3.9x10 M! Molecular gas exhausted in 200 Myr
• The Super-Antennae: (ULIRG) 12 -1 LIR=1.1x10 L! ! SFR= 190 M!yr 10 M(H2)=3x10 M! Molecular gas exhausted in 160 Myr Dusty starbursts at z~0 Definition #2 of a starburst: exceptional event b > 2-3 where : b=SFR/
SDSS data from Brinchmann et al. 04 Elbaz et al. 07 The SFR – stellar mass correlation:
Arp220
M82 MW The SFR – stellar mass correlation as a function of redshift
Arp220
M82 MW The SFR – stellar mass correlation as a function of redshift
Arp220
M82 MW
At z~1, LIRGs are no more outlyiers 10 All M*>5x10 M! are LIRGs or « dead » ! The SFR – stellar mass correlation as a function of redshift
Arp220
M82 MW
BzK galaxies (Daddi et al. 2005, 2007): 10 40% of M*"5x10 M! @ z=1.4-2.5 are ULIRGs 'z= 2 Gyr ! long duty cycle (> 400 Myr) 3=8=R%7#'S%,+'=M'7R&7##'%M'0*JE'0*'#;-P=&7':-%T+,M7##'=M>'#()*'=-7',+7'#=$7'U' !'+%T+'0*J'@'&"$9=&,'#,=-:;-#,#'
L8 ()'%M'>%#,=M,'7R&7##'0*J'T=8=R%7#'%#'$"-7'&"$9=&,'%M'-7#,5P-=$7'VW'
HST ACS-B(4350Å) @z~0.7 ! 2700Å
HST ACS-B(6060Å) @z~1.2 ! 2700Å
HST ACS-I(7750Å) @z~1.8 ! 2700Å >2;&/?$"3#17(#=/4/2(1&$.#./&&(.9/"#%/&#+@#3'4'5$(0A#
1/8'&)#'#-"$?(&0'4#>B#+CD#%/&#*+#'")#+E#3'4'5$(0' X-","5,.9%&=8'0*'(12'"P'Y=%M'(7O;7M&7'=M>'(,=-:;-#,'T=8=R%7#' Main Sequence Starburst : sSFR > 2 x sSFR(MS )
Main Sequence : broad far-IR bump 15 – 50 K, Starbursts : peaked far-IR bump 45 – 50 K, strong PAH features, ISM= 38 %, SF= 62 % SED weak PAH features, ISM= 0 %, SF= 100 % SED
Model fit: 2 components, "diffuse ISM" and "star forming region" Range of dust temperatures but ISM range wide
Tdust(ISM)~ 18 K , Tdust(SF)~ 50 K Main Sequence
Starburst
Galliano +08 >2;&/?$"3#17(#=/4/2(1&$.#./&&(.9/"#%/&#+@#3'4'5$(0#
CE01 library of template IR SEDs >2;&/?$"3#17(#=/4/2(1&$.#./&&(.9/"#%/&#+@#3'4'5$(0#
Unique IR SED for all galaxies: main sequence !&(#)$01'"1#3'4'5$(0#./4)('"#4/.'4#/"(0#:' 2"'S7'#77'=M.'7Z%>7M&7'P"-'=M'7Z"8;<"M'"P'[>;#,'Q'
Hwang, Elbaz +10 2"'S7'#77'=M.'7Z%>7M&7'P"-'=M'7Z"8;<"M'"P'[>;#,'Q'
FIR properties derived by the same method for all samples!s
4)*3'
]"&=8' IRAC bump selected galaxies: V]0*3#' Y=TM788%\'AD' Magdis +10 Fill the gap, no Tdust selection # SMGs prior to Herschel were biased # large dispersion in Tdust
Hwang, Elbaz +10 Magnelli +10, Magdis, Elbaz +10 , Chapman +10 IRAC peakers are missed by smm surveys
Y=T>%#'\AD' F/8'&)0#'"#'..-&'1(#)(1(&2$"'9/"## /%#17(#=/4/2(1&$.#/-1;-1#/%#3'4'5$(0A#
G'?(#8(#2$00()#0/2(#/=0.-&()#!HI0#:'
obscured AGNs
Compton thin
unobscured AGNs
Compton Thick AGNs (7=-&+%MT'P"-':;-%7>'^3_#'S%,+'0*J'6+7//#8+6'.-/9'#8,-7"-#:%+##'
X-ray AGNs Power-law AGNs
high & low IR8 : ~10% ! ~20% high IR8 : 15% ! 19% low IR8 : 33% ! 70% (7=-&+%MT'P"-':;-%7>'^3_#'S%,+'0*J'6+7//#8+6'.-/9'#8,-7"-#:%+##' F7(#*'$"#+(,-(".(#/%#01'&#%/&2$"3#3'4'5$(0#
• Distant (U)LIRGs are long-lasting events (few Gyrs !) contrary to local ones (200 Myr)
• Mostly "normal" galaxies, i.e. follow Main Sequence in Specific SFR, SF efficiency & LIR/L8
• IR8= LIR/L8 and SFR – M* confirm existence of a main sequence mode of SF : disk/extended
• Starbursts= compact SF with excess IR8, not directly related to LIR or SFR • Good representation of IR SED for MS and SB galaxies ! bolometric correction
10 11 ! LIRG = SB at z~0 but MS gal at z~1 if M*>5x10 M" (ULIRG@z=2 , M*>2x10 M") • Low far-IR/8um from dusty AGNs can be hidden by concommittant starbursts boosting IR8. ! after de-boosting IR8 from "starburstiness" : candidate population of obscured AGNs ! missing fraction of X-ray background ?... • 3 Main Sequences of SF galaxies ! Fundamental tryptic ~ fundamental plane for ellipticals ! Main Sequence galaxies dominate the cosmic SFR density at all redshifts ! ! The fall in cosmic SFR driven by the decrease in gas mass
Starbursts vs Main Sequence galaxies = progenitors of E's and Sp's ? [+7'P;M>=$7M,=8',-.9<&'"P'#,=-'P"-$%MT'T=8=R%7#'
SFR – L8 SFR – M* SFR – Mgas
SFR – L8 SFR – M* SFR – Mgas J(&0;(.9?(0'
ALMA and eMERLIN to study compactness of SF regions SINFONI to study dynamical stage of high IR8 galaxies IR SED - compactness relation = powerful technique for JWST
./012&%324325' Hernquist, Springel, di Matteo, Hopkins et al Cold flows: minor mergers & steady accretion Dekel +09 Dynamical Instabilities: Bournaud, Elmegreen
HORIZON simulation Ocvirk, Pichon, Teyssier 08