Monday, January 14, 2013

Jerusalem WS lecture notes: 16. Signatures of Inflows and Outflows

By R. Dave, slides here.
  • metals in diffuse IGM -- outflows!
  • at high z, SF can't keep up with inflow: the gas accumulation phase: gas can even turn into molecular phase, but due to low efficiency it won't all be processed into stars (equilibrium breaks down), RD 2012
  • eta scaling ~ M_{halo} ^{-1/3} -- z_{equil} ~ 5 for massive galaxies
  • equilibrium model code at
  • 'thesis back in the stone age'
  • constraining outflow parameters: direct observation and direct modelling are challenging
  • direct observation of preventive feedback:
    • mass in CGM: gas in absorption, X-ray emission, soft X-ray bg: COS (Cosmic Origins Spectrograph): OVI high ionisation line, 2 components: photo- and collisional excitation: SF galaxies are probing 300 000 K gas:, Anderson 2012
    • direct observations of ejective feedback: outflowing ISM lines: LBG tomography
    • direct observations of wind recycling: _metallicity_ of inflowing gas. Disk outskirts: \alpha_z ~ 0.3
  • indirect constraints:
    • counting statistics are not as good as scaling relations
    • galaxies to 0th order are a 1-parameter family (stellar or halo mass) --> good scaling parameters
    • conversion efficiency peaks at 10^{12} M_{\odot}
    • if you don't have winds, you have overcooling problems
    • cosmic SFR efficiency: SFR vs. Halo mass infall rate: a simple combination of model parameters (Behroozi et al), simulations are hard
    • SFR vs. M_{\odot}: galaxy MS is the parameter to compare SF galaxies across redshifts, not SFR -- present starbursts and past normal SF galaxies have identical SFRs
    • MS evolution is currently difficult to model
    • SFR -- metallicity relation
    • M_{star} -- feedback relation
    • M_{star} function -- Baldry 2008 simulations -- reproduces the lower mass GSMF well, arbitrary quenching at logM > 11, governed by differential recycling which flattens the relation at intermediate masses --> inflection
    • gas fractions and X_{co}
  • DLAs: kinematics favor ejection, not prevention, CDM has many low-mass halos, if they have many HI, too many narrow DLAs result

No comments:

Post a Comment