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Feedback & Large Surveys

Feedback & Large Surveys. Harry Ferguson (STScI). Feedback. SNe. Quasar mode AGN. ( SNe ). Radio Mode AGN. UV back-ground. Halo quenching. Satellites: Ram pressure, tides, shocks…. Behroozi + 2011. AGN feedback in SAMs. Somerville+ 2008

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Feedback & Large Surveys

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  1. Feedback & Large Surveys Harry Ferguson (STScI)

  2. Feedback SNe Quasar mode AGN (SNe) Radio Mode AGN UV back-ground Halo quenching Satellites: Ram pressure, tides, shocks… Behroozi+ 2011

  3. AGN feedback in SAMs • Somerville+ 2008 • AGN quenching successfully reduces the stellar masses at the bright end. • Somewhat degenerate with simple “halo quenching”

  4. Mergers & QSOs • Hopkins+ 2006 used numerical simulations to determine the relation between merger lifetimes & luminosities and QSO lifetimes & luminosities. • Inferred contribution of mergers to the SFRD at z~2 is 30-50%.

  5. Quenching high-mass galaxies • Successful models of feedback affect star-formation differentially along the mass sequence. • Therefore statistical constraints on SFR(t,M) have the potential to distinguish between mechanisms. Gabor+ 2010

  6. Successes of Feedback models • Qualitative understanding of: • For galaxies: • Mass-metallicityrelation • Star-formation efficiency as a function of halo mass • Red-sequence/blue-sequence • Clustering of SMGs, Early type galaxies, QSOs • For AGN: • QSO lifetimes • AGN column-density distributions • QSO clustering • Cluster entropy floor

  7. Example: Clustering Hickox+ 2012 Correlation length of sub-millimeter galaxies, QSOs & bright ellipticals are comparable Evolutionary scenario for high-mass galaxies:

  8. Key Observational tests? • Measurements of feedback • Wind momenta • Galaxy ICM temperatures • BH-mass stellar-mass relations with redshift • Improved clustering measurements • Red-sequence Evolution • AGN Host morphologies • Metallicity-dependent SFRs

  9. Linking morphology to merger-driven feedback

  10. Challenges • Observational • Disk galaxy properties • Simultaneously matching disk galaxy mass function, mass-metallicity, Tully Fisher relation & bulge fraction • Spheroidal galaxy sizes & evolution • SMGs are disks? (not mergers – Targett+ 2011,12) • Morphologies of AGN hosts (Kocevski 2012) • Moderate-luminosity AGN • Merger or instability driven? • Is feedback from these AGN inportant? • Theoretical • Dynamic range • Microphysics of feedback

  11. SMGs are disks? • Targett+ 2011,12 • The mass-dominant components of SMGs appear to be disk-like

  12. CANDELS AGN Hosts at z~2 • Undisturbed disks are the most common morphology • AGN hosts do not show irregular morphologies any more often than a mass-matched sample of non-active control galaxies. • Merger fraction is unexpectedly low. • Implication for AGN fueling theory: If disks have not experienced major merger in recent past, then stochastic internal accretion may play a greater role in fueling AGN activity at z~2 than expected. Kocevski+ 2012

  13. Challenges: Disk galaxy properties Scannapieco+ 2012 With the same initial conditions, different models built very different galaxies. None particularly successful.

  14. Models already diverge at z=5

  15. Questions • What is the relative importance of ejective vs. preventative feedback? • What is the relative importance of environmental quenching vs. mass quenching? • What is the relative importance of mergers vs. smooth star formation? • How can we tell?

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