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Star Formation from Herschel deep surveys

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. Importance of the FIR & submm.

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Star Formation from Herschel deep surveys

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  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

  2. Importance of the FIR & submm • 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 Credit: WMAP

  3. GOODS-Herschel (Herschel Open Time Key Program)The Great Observatories Origins Deep Survey : far IR imaging with Herschel Deepest images of the sky in the 2 GOODS fields : 1818 sources down to 1 mJy at 100 mm, 2.6 mJy@160mm, 5mJy@250mm, 8mJy@350mm, 10mJy@500mm X UV U B V I Z J H K 3.6m 4.5m 5.8m 8m IRS16 MIPS24radio 2x10-16erg/s/cm2~28AB 22AB ~1Jy 50Jy 20Jy12Jy Collaborators (60):Fr, US, G, UK, Gr, It, Can, ESO, ESA 362.6 hours (100m & 160m PACS + 31h SPIRE) Herschel:350 cm 70% complete spec z ~30% phot z • cosmic SFR density : normal galaxies up to z ∼ 1, LIRGs up to z∼ 2, ULIRGs to z~4 • bridge IR and UV up to z ∼ 1.5 ... 4 • identify missing obscured AGNs making the missing cosmic X-ray background (30 keV) GOODS-North GOODS-South 100160 250 24100160 10'x15' 10'x10'

  4. GOODS-Herschel (Herschel Open Time Key Program)The Great Observatories Origins Deep Survey : far IR imaging with Herschel Deepest images of the sky in the 2 GOODS fields : 1818 sources down to 1 mJy at 100 mm, 2.6 mJy@160mm, 5mJy@250mm, 8mJy@350mm, 10mJy@500mm X UV U B V I Z J H K 3.6m 4.5m 5.8m 8m IRS16 MIPS24radio 2x10-16erg/s/cm2~28AB 22AB ~1Jy 50Jy 20Jy12Jy Collaborators (60):Fr, US, G, UK, Gr, It, Can, ESO, ESA 362.6 hours (100m & 160m PACS + 31h SPIRE) Herschel:350 cm 70% complete spec z ~30% phot z 70% complete spec z ~30% phot z • cosmic SFR density : normal galaxies up to z ∼ 1, LIRGs up to z∼ 2, ULIRGs to z~4 • bridge IR and UV up to z ∼ 1.5 ... 4 • identify missing obscured AGNs making the missing cosmic X-ray background (30 keV) GOODS-North GOODS-South 100160 250 24100160 10'x15' 10'x10'

  5. 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) LIR (Herschel) CE01 Elbaz +10, 11, Nordon +10 LIR(from 24mm using CE01)

  6. The mid-IR excess problem... SED evolution/AGN/k-correction ?... Elbaz +11 LIR (Herschel) LIR (Herschel) LIR(from 24mm using CE01) L8(rest-frame from Spitzer)

  7. IR main sequence : 2 modes of star formation ? Elbaz +11

  8. IR main sequence : the role of SF compactness >3x1010 Lkpc-2 • radio size NVSS & FIRST 20cm: 1" ~0.5 kpc res° • 13.2mm compactness : 3.6" ~1.7 kpc resolution • Spitzer-IRS spectroscopy (spatial profile along slit) & IRAC-8mm imaging (Diaz-Santos +10) Elbaz +11

  9. IR8 = LIR / L8 IR main sequence : the role of SF compactness LIR (IRAS) SIR L8(rest-frame) Local Elbaz +11

  10. Galaxies with an excess in IR8, IR surface brightness and sSFR are the same ! high IR8 ~ compact starbursts SFR LIR (IRAS) M* L8 RSB=sSFR/sSFR(Main Seq.) sSFR= SFR/ M* (Gyr-1) SIR IR8 = LIR / L8

  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

  12. Proto-typical IR SED of Main Sequence and Starburst galaxies Main Sequence Starburst (high IR8, sSFR) Nordon +11 Starbursts : peaked far-IR bump 45 – 50 K, weak PAH features, ISM= 0 %, SF= 100 % SED Main Sequence : broad far-IR bump 15 – 50 K, strong PAH features, ISM= 38 %, SF= 62 % 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

  13. IR8=LIR/L8 as a tracer of star formation geometry ( mergers) Galliano +08

  14. Improving the bolometric correction for SF galaxies Unique IR SED for all galaxies: main sequence Elbaz +11

  15. Two modes of star formation 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

  16. The Σ(SFR)/M ~z relation up to z~1.6 Black points: clusters Magenta points: groups Red star: the Bullet cluster Blue region: field galaxy halos

  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

  18. The Σ(SFR)/M ~z relation up to z~1.6 Cluster desert 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

  19. 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

  20. Document title | Author Name | Place | Data doc | Programme | Pag. 22

  21. 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%

  22. Searching for buried AGNs with IR8 deboosted from starburstiness 2% +15% src with high IR8 17% 25%

  23. 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 ~85 % ~15% <5% (% age after recombination) rSFR (Myr-1Mpc-3) 8% z~3 15% z~2 50% z~1 redshift rstar (MMpc-3) Marchesini +09 redshift Le Borgne, Elbaz, Ocvirk, Pichon 10

  24. 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

  25. GOODS-Herschel (Herschel Open Time Key Program)The Great Observatories Origins Deep Survey : far IR imaging with Herschel Deepest images of the sky in the 2 GOODS fields : 1818 sources down to 1 mJy at 100 mm, 2.6 mJy@160mm, 5mJy@250mm, 8mJy@350mm, 10mJy@500mm X UV U B V I Z J H K 3.6m 4.5m 5.8m 8m IRS16 MIPS24radio 2x10-16erg/s/cm2~28AB 22AB ~1Jy 50Jy 20Jy12Jy Collaborators (60):Fr, US, G, UK, Gr, It, Can, ESO, ESA 362.6 hours (100m & 160m PACS + 31h SPIRE) Herschel:350 cm 70% complete spec z ~30% phot z • cosmic SFR density : normal galaxies up to z ∼ 1, LIRGs up to z∼ 2, ULIRGs to z~4 • bridge IR and UV up to z ∼ 1.5 ... 4 • identify missing obscured AGNs making the missing cosmic X-ray background (30 keV) GOODS-North GOODS-South 100160 250 24100160 10'x15' 10'x10'

  26. The ‘infrared main sequence’ for star-forming galaxies • 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 Document title | Author Name | Place | Data doc | Programme | Pag. 28

  27. The typical Spectral Energy Distribution of main-sequence and starburst galaxies: 2 modes of star formation 10% 90% Starbursts= mergers between late-types, ~10% of cosmic SFR density

  28. 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

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