Feedback & Large Surveys Harry Ferguson (STScI)

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

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

Mergers & QSOs  Hopkins 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%.

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

Successes of Feedback models  Qualitative understanding of:  For galaxies:  Mass-metallicity relation  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

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

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

Linking morphology to merger- driven feedback

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

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

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

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

Models already diverge at z=5

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?