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With: V. Smolcic , A. Karim , ,

With: V. Smolcic , A. Karim , , B. Magnelli , A.Zirm , M. Michalowski, P. Capak , K. Sheth , K. Schawinski , S. Wuyts , D. Sanders, A. Man, D. Lutz, J. Staguhn , S. Berta, H. McCracken, . Dark Group A. Zirm , A. Man, J.-K. Krogager , K. Olsen.

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With: V. Smolcic , A. Karim , ,

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  1. With: V. Smolcic, A. Karim,, B. Magnelli, A.Zirm, M. Michalowski, P. Capak, K. Sheth, K. Schawinski, S. Wuyts, D. Sanders, A. Man, D. Lutz, J. Staguhn, S. Berta, H. McCracken, Dark Group A. Zirm, A. Man, J.-K. Krogager, K. Olsen The highest redshift Sub-mm galaxies as progenitors of compact quiescent galaxies Sune Toft Dark Cosmology Centre

  2. “Connecting the Extreme”

  3. Compact Quiescent Galaxies at z=2 (cQGs) Photometric surveys: The fraction of quiescent galaxies increases rapidly between z=3 and 2 At z=2, half of the most massive galaxies are quiescent with little ongoing star formation and evolved stellar populations ncQG=6.0±2.1 × 10-5 Mpc-3 (Brammer++, 2011), Ilbert et al 2012)

  4. Restframe optical absorption line spectroscopy Broad wavelength continuum fits: Post-Starburst with strong Balmer abs. Line indices: Metal rich, 1-2 Gyr old Velocity dispersions 300-500 km/s (e.g. Toft et al 2012; van de Sande et al 2012, Onodera et al, 2012 )

  5. Spectroscopic sample of z=2 cQGS COSMOS 3DHST+CANDLES • Strong 4000A break z-spec • SED fit  M*, Av, age, zform • Galfit HST/F160W  size “Complete” (Krogager, Zirm, Toft, Man & Brammer, ApJ (Submitted))

  6. Mass-size relation (complete spectroscopic sample) 3DHST/CANDELS: The mass-size relation at z=2 is shifted to ~3 times smaller sizes at a given mass, with respect to the local relation (slope & scatter identical) >10 times larger stellar mass densities (Krogager, Zirm, Toft & Brammer, 2013)

  7. How did they form? NIR spectroscopy: • Post-starburst spectra • Baryon dominated • Some dust (Av=0-1) • 1-1.5 Gyr -> zform>3 (Toft++2012, van de Sande++2012, Onodera++2012, K13) “Main sequence” star forming galaxies at z>3? • SFRmin>115 M/yr from z=10 to zform >3 times higher than observed for z=3 LBGs (Carilli++ 2008) • Number density of z>3 LBGs with M>1011 M<< ncQG(Stark++ 2009) -> Progenitors must be dust obscured starbursts (Krogager++, 2013)

  8. Dust obscured nuclear starbursts? Sub-mm galaxies: • Prime examples of high-z dusty nuclear starbursts • Many authors have suggested a connection to cQGs(e.g. Tacconi++2006, Capak++2008, Toft++2009, Riechers++2013) Simulations of gas rich major mergers (Hopkins++ 2006) (Wuyts ++ 2010) Remnants very compact, concentrated (high sersic n)

  9. SMGs as progenitors? At z=2 SMGs (probed through CO emission), have many similarities with cQGs (probed through their stars) cQG SMGs M* >1011 M>1011 M Int. Velocity (σ★)=300-500km/sFWHMCO(1-0)=350-800 km/s <velocity> <σ★>=363 ±30 km/s <Vc>=392 ±134 km/s <size> <re>=2.0 ± 0.2 kpc <re>= 2.0 ± 0.3 kpc <Mdyn> (2.3 ± 1.4) ×1011 M(2.5 ± 1.3) ×1011 M <Redshift> zform> 3 <z>obs =2 (Tacconi et al 2006, 2008, Ivison et al 2011 van de Sande et al 2012, Toft et al 2012, , Krogager et al in prep,)

  10. High redshift SMG sample COSMOS Aztec/JCMT/SMA sample “Statistical Sample”: Flux (F1.1mm>4.2mJy) & S/N (>4.5) –limited over 0.15☐o Redshifts peak at <z>=3 11 galaxies with z>3 (5 with spec-z) n(z>3) = 2.1 ± 0.4 × 10-6 Mpc-3 (Smolcicet al 2012)

  11. Redshift distribution match cQG (zform) SMG (zobs)

  12. SMG surface brightness fits Fit 2D surface brightness profiles with galfit Stacked YJHK UltraVISTA images (WFC3/F160W where avail) Very compact, small sersic n >Half have bright multiple components

  13. Mass-size relation z=2 cQG z>3 SMG

  14. Duty cycle of SMG starburst 1: Assume : -SMGs are direct progenitors of cQGs -Each progenitor only undergo one SMG phase 2: Require number densities to match: • Consistent with Independent estimates tburst= 40-200 Myr (gas depletion, clustering analysis, merger simulations) • Relatively independent of IMF nSMG,z>3= 2.1 ± 0.4 × 10-6 Mpc-3 nq,z=2= 6.0 ± 2.1 × 10-5 Mpc-3 Timescale of SMG starburst tburst (duty cycle)

  15. MIR-FIR SED fits Fit FIR SEDs with DL07 models Data: Spitzer MIPS, Herschel PACS, SPIRE, AzTEC, LABOCA, MAMBO, SMA, CARMA, PdBI Derive: LIR, SFR, Mdust, Mgas

  16. Eddington Limited Bursts? z=2 cQG z>3 SMG Maximum SFR of cQGs during formation (Eddington limited burst) (Younger et al 2010)

  17. Additional Stellar mass growth Z>3 stellar mass distribution broader than that of z=2 cQGs Ongoing starbursts in the SMG will increase their stellar mass ΔM★ ~ Mgas× η Star formation effeciency η~0.1-0.15 (Hayward++ 2011) Mgasfrom from Mdust (derived from FIR SED fits) assuming a mass and metallicity dependent dust-to-gas ratio z=2 cQG z>3 SMG

  18. Quenching by Active Galactic Nucleii? CDFS X-ray observations Deepest X-ray observations (4 million seconds) 22% (Olsen, Rasmussen, Toft & Zirm, 2013) Stack: 50x4 Ms = 200 Ms 70-100% of z=2 quiescent galaxies host AGN

  19. “Connecting the Extreme” (Toft et al , 2014)

  20. Summary Credit: HST press office

  21. Extra slides

  22. Star formation efficiency Disc Merger Gas fraction decrease by 10-15% from peak of starburst to when it is quenched (Hayward++, 2011)

  23. Transition population Population of compact starforming galaxies at z~3 with depressed SFR and enhanced AGN fraction. Not quiet as massive, but sizes and number densities match z=2 cQGs (Barro++, 2012)

  24. Descendants of z=2 SMGs (Bezanson ++2013) Population of compact post starburst galaxies at z=1.5, with high stellar and dynamical masses and zform~2

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