We explore new observationally-constrained sub-resolution models of galactic outflows and investigate their impact on the circumgalactic medium ( CGM ) in the redshift range z = 2 - 4 .
We perform cosmological hydrodynamic simulations , including star formation , chemical enrichment , and four cases of SNe-driven outflows : no wind ( NW ) , an energy-driven constant velocity wind ( CW ) , a radially varying wind ( RVWa ) where the outflow velocity has a positive correlation with galactocentric distance ( r ) , and a RVW with additional dependence on halo mass ( RVWb ) .
Overall , we find that the outflows expel metal-enriched gas away from galaxies , significantly quench the star formation , reduce the central galactic metallicity and enrich the CGM .
At z = 2 , the radial profiles of gas properties around galaxy centers are most sensitive to the choice of the wind model for halo masses in the range ( 10 ^ { 9 } -10 ^ { 11 } ) M _ { \odot } .

We infer that the RVWb model is similar to the NW case , except that it substantially enriches the CGM : the carbon metallicity ( Z _ { C } ) is 10 times higher in RVWb than in NW at r \geq R _ { 200 } ; and the warm gas of 10 ^ { 4 } -10 ^ { 5 } K and \delta < 100 is enriched at a level \sim 50 times higher than in NW .
Moreover , we find that the impact of models CW and RVWa are similar , with the following notable differences .
RVWa causes a greater suppression of star formation rate at z \leq 5 , and has a higher fraction of low-density ( \delta < 10 ) , warm-hot ( 10 ^ { 4 } -10 ^ { 6 } K ) gas than in CW . Z _ { C } in the CW model increases monotonically with \delta at \delta \leq 10 , while in RVWa Z _ { C } first decreases and then remains constant over the same density range .
Outflows in CW produce a higher and earlier enrichment of some IGM phases than RVWa : the warm 10 ^ { 4 } -10 ^ { 5 } K , \delta \sim 10 - 100 phase is enriched 10 times more and at z = 4 the underdense \delta \sim 0.1 - 0.8 warm-hot 10 ^ { 5 } -10 ^ { 7 } K gas has already a median Z _ { C } \sim 0.002 Z _ { C, \odot } in CW .
By visual inspection , we note that the RVWa model shows bipolar outflows and galactic disks more pronounced than in all the other wind models .
We present simple fitting formulae for the Z _ { C } as a function of gas density and of the galactocentric distance , also for the abundance of triply ionized carbon ( CIV ) as a function of the galactocentric distance .
We predict observational diagnostics to distinguish between different outflow scenarios : Z _ { C } of the CGM gas at r \sim ( 30 - 300 ) h ^ { -1 } kpc comoving , and CIV fraction of the inner gas at r < ( 4 - 5 ) h ^ { -1 } kpc comoving .