1. Quiescent and Starbursting star-forming galaxies at z=2 Giulia Rodighiero (University of Padova) On behalf of the PEP Team Trieste - The Physics of Star Formation – 18 October 2012 COSMOS 24/100/160 μm

3. The Main Sequence of Star-forming galaxies at 1.4 < z < 2.5

4. Two regimes of star formation: quasi-steady on the main sequence, starbursts off of it (Daddi et al 2010)

5. Two regimes of star formation: quasi-steady on the main sequence, starbursts off of it

6. Answering with HERSCHEL/PACS observations over the GOODS & COSMOS fields

7. The PEP- GOODS South (Lutz et al. 2011) ~ 21’x14’

8. The PEP-COSMOS ~2 square degrees

9. HERSCHEL/PACS observations over the GOODS & COSMOS FIELDS Rodighiero et al. (2011)) Data-set required to fully sample the stellar mass – SFR plane: 1.PACS 100μm and 160μm shallow source catalogs with extraction based on 24μm prior positions + IRAC-selected source catalog from Ilbert et al. (2010) 2.PACS 70, 100 and 160μm deep catalog in GOODS-S + multiwavelength photometry, spec & photo-z 3.BzK COSMOS catalog (Daddi/McCracken) 4.BzK GOODS-S catalog (Daddi et al. 2007)

10. SFR: derived from SED fitting to the complete UV-to-PACS observed photometry and converting the bolometric emission ([8-1000]μm) with the Kennicutt et al. (1998) relation (inclusion of unobscured SF does not affect the results). STELLAR MASSES: classical SED fitting to the UV-to-IRAC (5.8μm) with Bruzual & Charlot models

11. Populating the mass-SFR plane

12. BzK PACS-deep PACS-shallow X 4-MS

13. Number densities as a function of mass and SSFR bins: defining the ON & OFF main sequence loci

14. SFR density: % OFF sequence ~10% Number density: % OFF sequence ~2% SFR density Number density ON and OFF sequence

15. Kaviraj et al. 2012 (arXiv 1210.2160) Morphological WFC3/HST analysis in GOODS-S: The actual major-merger contribution to the star formation budget may be as low as~15%

16. DUTY CYCLE ON/OFF the MAIN SEQUENCE at 1.5<z<2.5 With only ∼ 2% of the massive galaxies being OFF the main sequence, on average each galaxy spends 20 Myr in the starburst mode. This is actually much shorter than both the gas depletion timescale (~0.5 Gyr) and the dynamical time in starburst galaxies (~50-200 Myr, Daddi et al. 2010; Genzel et al. 2010). Not all galaxies may experience a (merger-driven) starburst during these ~2 Gyr of cosmic time interval.

17. ON- and OFF-main sequence IR Luminosity functions PEP/HERMES-COSMOS-GOODS-ECDFS sources Predictions from Sargent et al. 2012 Gruppioni et al. (2012) ON-MS OFF-MS

18. The integrated bolometric LFs confirm the dominant role of the main sequence population at 1<z<2 for the mass assembly, both in number and luminosity/SFR densities. Gruppioni et al. (2012)

19. MAIN CONCLUSION The merger-enhanced SFR phases are relatively unimportant for the stellar mass growth of z ∼ 2 galaxies, and probably so at all redshifts. Still, going through a merging-driven starburst phase may turn star-forming galaxies into passive ellipticals. TESTING THE STARBURST-MERGER PARADIGM

20. ASI ReviewPadova Science Activities20 Follow-up campaign of extreme off-sequence Herschel sources at z=2 (1) P.I. G. Rodighiero

21. IRAM PdB CO(2-1) line: PACS-164 5-σ detection at z=1.646 Data analysis by Chiara Feruglio

22. Daddi et al. (2010) L(IR)/L(CO) larger than BzK sources

23. Daddi et al. (2010) Assuming a “starburst” α(CO) value The S-K relation (preliminary!!)

24. ASI ReviewPadova Science Activities24 Follow-up campaign of extreme off-sequence Herschel sources at z=1.5 (2) P.I. J. Silverman

25. The AGN population in the mass-SFR plane: a key test to constrain the AGN feedback and the joint black-hole/star-formation accretion rate The “Hidden AGN Main Sequence” at z~1 and z~2: the same secular processes that drive the bulk of star formation are also responsible for the majority of SMBH growth (Mullaney et al. 2012) AGNs reside mostly in main-sequence hosts, reflecting the AGN - sSFR connection (Rovilos et al. 2012)

26. Herschel COSMOS Obscured AGN: F(24μm)/F(R)>1000 & (R-K)>4.5 (Fiore et al. 2008) Herschel GOODS X-ray selected AGN (with thanks to P. Popesso & M. Brusa) Singularly detected AGN seem to live preferentially on the Main Sequence

27. The most SB sources: x10>MS Dominated by SFR Obscured AGN present but does never dominate the bolometric far-IR emission

28. SED fitting of Herschel sources with local empirical templates Type 1 AGN Type 2 AGN Low Luminosity AGN Starburst Spirals/quiescent SFR (from C. Gruppioni SED fitting) Hard to derive trends….

29. SED fitting with energy balance (Da Cunha et al. 2008/2010) + dusty torus component (Berta et al. in prep.):  Hidden AGN fraction in the mid-IR and far-IR observed

30. Test case at 1.4<z<1.7 (preliminary…) ON OFF Increasing AGN fraction (from 10% to 70%) Obscured AGN homogeneously distributed on the mass-SFR plane (at least in bright LIR limited samples)

31. P.I. John Silverman

33. Broad emission lines consistent with nuclear activity Courtesy of J. Silverman

34. X 4-MS Overall test with X-ray stacking in different mass-SFR bins (in progress…):

35. SUMMARY - Majority of star formation at high-z takes place on the MS - Outliers to the MS are starbursts also in the Schmidt- Kennicutt plane (tentative… well ok  … one source … but more to come!) - AGN activity and SFR are well correlated along the MS, what’s above? - Ideas, suggestions…?

36. FOR DiSCUSSION: underestimation of stellar mass in heavily extinguished galaxies Poster & paper (submitted) by Barbara Lo Faro Dead off-MS? sSFR of starbursts would drop down (by a factor ~6- 10!)…

37. Thank you!