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Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #1
Star Formation from Herschel deep surveys
B. Altieri, on behalf of
• PEP (PACS Extragalactic Probe,
PI D. Lutz ) GT Key Program consortium
• GOODS-Herschel (PI, D. Elbaz) OT Key program
Elbaz+11, Popesso+11, Rodighiero+11, Mullaney+11
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #2
Credit: WMAP
– Half of the energy created in the Universe since the CMB has been reprocessed into the IR
– Herschel covers the IR peak and pushes into the submillimetre
Importance of the FIR & submm
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #3
Collaborators (60): Fr, US, G, UK, Gr, It, Can, ESO, ESA
362.6 hours (100m & 160m PACS + 31h SPIRE)
GOODS-Herschel (Herschel Open Time Key Program)The Great Observatories Origins Deep Survey : far IR imaging with Herschel
1. cosmic SFR density : normal galaxies up to z ∼ 1, LIRGs up to z∼ 2, ULIRGs to z~4
2. bridge IR and UV up to z ∼ 1.5 ... 4
3. identify missing obscured AGNs making the missing cosmic X-ray background (30 keV)
Herschel: 350 cm
Deepest images of the sky in the 2 GOODS fields :1818 sources down to
1 mJy at 100 m, 2.6 mJy@160m, 5mJy@250m, 8mJy@350m, 10mJy@500m
X UV U B V I Z J H K 3.6m 4.5m 5.8m 8m IRS16 MIPS24 radio2x10-16erg/s/cm2 ~28AB 22AB ~1Jy 50Jy 20Jy 12Jy
70% complete spec z~30% phot z
GOODS-North100 160 250 GOODS-South
24 100 16010'x15' 10'x10'
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #4
Collaborators (60): Fr, US, G, UK, Gr, It, Can, ESO, ESA
362.6 hours (100m & 160m PACS + 31h SPIRE)
GOODS-Herschel (Herschel Open Time Key Program)The Great Observatories Origins Deep Survey : far IR imaging with Herschel
1. cosmic SFR density : normal galaxies up to z ∼ 1, LIRGs up to z∼ 2, ULIRGs to z~4
2. bridge IR and UV up to z ∼ 1.5 ... 4
3. identify missing obscured AGNs making the missing cosmic X-ray background (30 keV)
Herschel: 350 cm
Deepest images of the sky in the 2 GOODS fields :1818 sources down to
1 mJy at 100 m, 2.6 mJy@160m, 5mJy@250m, 8mJy@350m, 10mJy@500m
X UV U B V I Z J H K 3.6m 4.5m 5.8m 8m IRS16 MIPS24 radio2x10-16erg/s/cm2 ~28AB 22AB ~1Jy 50Jy 20Jy 12Jy
70% complete spec z~30% phot z
GOODS-North100 160 250 GOODS-South
24 100 16010'x15' 10'x10'
70% complete spec z~30% phot z
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #5
• 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)
Elbaz +10, 11, Nordon +10
The mid-IR excess problem... SED evolution/AGN/k-correction ?...
CE01
LIR (Herschel)
LIR(from 24m using CE01)
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #6
The mid-IR excess problem... SED evolution/AGN/k-correction ?...
Elbaz +11LIR (Herschel)
LIR(from 24m using CE01)
LIR (Herschel)
L8(rest-frame from Spitzer)
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #7 Elbaz +11
IR main sequence : 2 modes of star formation ?
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #8
IR main sequence : the role of SF compactness
>3x1010 Lkpc-2
• radio size NVSS & FIRST 20cm: 1" ~ 0.5 kpc res°• 13.2m compactness : 3.6" ~ 1.7 kpc resolution Spitzer-IRS spectroscopy (spatial profile along slit) & IRAC-8mm imaging (Diaz-Santos +10)
Elbaz +11
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #9
IR main sequence : the role of SF compactness
Local
L8(rest-frame)
LIR (IRAS)
Elbaz +11
IR8 = LIR / L8
IR
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #10
L8
LIR (IRAS)
sSFR= SFR / M* (Gyr-1)
IR
RSB=sSFR/sSFR(Main Seq.)
IR8 = LIR / L8
SFR
M*
Galaxies with an excess in IR8, IR surface brightness and sSFR are the same ! high IR8 ~ compact starbursts
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #11
SF in distant excess IR8 galaxies is more compact in rest-frame UV
HST ACS-B(4350Å) @z~0.7 2700Å
HST ACS-V(6060Å) @z~1.2 2700Å
HST ACS-I(7750Å) @z~1.8 2700Å
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #12
Proto-typical IR SED of Main Sequence and Starburst galaxiesMain Sequence Starburst (high IR8, sSFR)
Model fit: 2 components, "diffuse ISM" and "star forming region"Range of dust temperatures but ISM range wideTdust(ISM)~ 18 K , Tdust(SF)~ 50 K
Main Sequence : broad far-IR bump 15 – 50 K, strong PAH features, ISM= 38 %, SF= 62 % SED
Starbursts : peaked far-IR bump 45 – 50 K, weak PAH features, ISM= 0 %, SF= 100 % SED
Nordon +11
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #13
IR8=LIR/L8 as a tracer of star formation geometry ( mergers)
Galliano +08
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #14
Improving the bolometric correction for SF galaxies
Unique IR SED for all galaxies:main sequence
Elbaz +11
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #15
ConclusionsTwo
• Distant (U)LIRGs = normal star-forming galaxies + large Mgas, long-lasting (Gyrs)
• IR8= LIR/L8 universal among star-forming galaxies geometry of SF regions (robust / fragile dust ratio)
• High IR8 values for compact starbursts with high SFR / M* (mergers)
• Main Sequence galaxies (disk-like) dominate the cosmic SFR density at all redshifts !
The fall in cosmic SFR driven by the decrease in gas mass not merger rate
• Starbursts= mergers between late-types, ~10% of cosmic SFR density
• IR SED for MS and SB galaxies bolometric correction
LIRG = SB at z~0 but MS at z~1 if M*>5x1010 M(ULIRG@z=2 , M*>2x1011 M)
• IR dominated by star formation in AGNs (LX<1042-44 erg s-1)
Next: improve SED library by bins in sSFR, IR8, Lir
Two modes of star formation
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #16
The Σ(SFR)/M ~z relation up to z~1.6The Σ(SFR)/M ~z relation up to z~1.6
Black points: clustersMagenta points: groups
Red star: the Bullet clusterBlue region: field galaxy halos
Black points: clustersMagenta points: groups
Red star: the Bullet clusterBlue region: field galaxy halos
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #17
The Σ(SFR)/M ~z relation up to z~1.6
Conclusions:•pre-processing ruled out•quenching effect takes place after merger/accretion (likely environmental)•Reversal of SFR-density at z> 1.5
Conclusions:•pre-processing ruled out•quenching effect takes place after merger/accretion (likely environmental)•Reversal of SFR-density at z> 1.5
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #18
The Σ(SFR)/M ~z relation up to z~1.6
Future: HSC GT1 and hopefully OT2 time to search for proto-clusters + 100h of Herschel/PACS (PI P. Popesso) to observe 8 groups/clusters in the cluster desert at 1.5 < z < 2
Future: HSC GT1 and hopefully OT2 time to search for proto-clusters + 100h of Herschel/PACS (PI P. Popesso) to observe 8 groups/clusters in the cluster desert at 1.5 < z < 2
Cluster desert
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #19
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #21
Star Formation from Herschel deep surveys
B. Altieri, on behalf of
• PEP (PACS Extragalactic Probe,
PI D. Lutz ) GT Key Program consortium
• GOODS-Herschel (PI, D. Elbaz) OT Key program
Elbaz+11, Popesso+11, Rodighiero+11, Mullaney+11
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #22
Document title | Author Name | Place | Data doc | Programme | Pag. 22
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #23
Searching for buried AGNs with IR8 deboosted from starburstiness
X-ray AGNs Power-law AGNs
high IR8 : 15% 19%low IR8 : 33% 70%
high & low IR8 : ~11% ~22%
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #24
Searching for buried AGNs with IR8 deboosted from starburstiness
2%
17%
25%
+15% src with high IR8
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #25
• what is the redshift by which half of the stars that we see today were formed ?(Peebles 1988, The epoch of galaxy formation)
z 0 – 2.5 2.5 – 5 5 - ∞votes in 1988 28 54 4
Marchesini +09
50%z~1
15%z~2
8%z~3
Le Borgne, Elbaz, Ocvirk, Pichon 10
SFR (Myr-1Mpc-3)
redshift
redshift
star (MMpc-3)
~85 % ~15% <5% (% age after recombination)
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #26
Star Formation from Herschel deep surveys
B. Altieri, on behalf of
• PEP (PACS Extragalactic Probe, PI D. Lutz ) GT Key Program consortium
• GOODS-Herschel (PI, D. Elbaz) OT Key program
Elbaz+11, Popesso+11, Rodighiero+11, Mullaney+11
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #27
Collaborators (60): Fr, US, G, UK, Gr, It, Can, ESO, ESA
362.6 hours (100m & 160m PACS + 31h SPIRE)
GOODS-Herschel (Herschel Open Time Key Program)The Great Observatories Origins Deep Survey : far IR imaging with Herschel
1. cosmic SFR density : normal galaxies up to z ∼ 1, LIRGs up to z∼ 2, ULIRGs to z~4
2. bridge IR and UV up to z ∼ 1.5 ... 4
3. identify missing obscured AGNs making the missing cosmic X-ray background (30 keV)
Herschel: 350 cm
Deepest images of the sky in the 2 GOODS fields :1818 sources down to
1 mJy at 100 m, 2.6 mJy@160m, 5mJy@250m, 8mJy@350m, 10mJy@500m
X UV U B V I Z J H K 3.6m 4.5m 5.8m 8m IRS16 MIPS24 radio2x10-16erg/s/cm2 ~28AB 22AB ~1Jy 50Jy 20Jy 12Jy
70% complete spec z~30% phot z
GOODS-North100 160 250 GOODS-South
24 100 16010'x15' 10'x10'
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #28
The ‘infrared main sequence’ for star-forming galaxies
Document title | Author Name | Place | Data doc | Programme | Pag. 28
• Main Sequence galaxies (disk-like) dominate the cosmic SFR density at all redshifts !
• The fall in cosmic SFR driven by the decrease in gas mass not merger rate
Elbaz+ 2011
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #29
The typical Spectral Energy Distribution of main-sequence and starburst galaxies: 2 modes of star formation
Starbursts= mergers between late-types, ~10% of cosmic SFR density
90% 10%
Bruno Altieri | Toledo 2011 | 23 Nov. 2011 | vg #30
Conclusions
Distant (U)LIRGs = normal star-forming galaxies + large Mgas, long-lasting (Gyrs)
IR8= LIR/L8 universal among star-forming galaxies geometry of SF regions
High IR8 values for compact starbursts with high SFR / M* (mergers)
Main Sequence galaxies (disk-like) dominate the cosmic SFR density at all redshifts !
The fall in cosmic SFR driven by the decrease in gas mass not merger rate
Starbursts= mergers between late-types, ~10% of cosmic SFR density
IR SED for MS and SB galaxies bolometric correction
LIRG = SB at z~0 but MS at z~1 if M*>5x1010 M (ULIRG@z=2 , M*>2x1011 M)
IR dominated by star formation in AGNs (LX<1042-44 erg s-1)TBD: improve SED library by bins in sSFR, IR8, Lir