Supernovae and AGN driven galactic outflows
  We present analytical solutions for winds from galaxies with NFW dark matter
halo. We consider winds driven by energy and mass injection from multiple
supernovae, as well as momentum injection due to radiation from a central black
hole. We find that the wind dynamics depends on three velocity scales: (a)
v_star \sim (\dot{E} / 2 \dot{M})^{1/2} describes the effect of starburst
activity, with \dot{E}, \dot{M} as energy and mass injection rate in a central
region of radius R; (b) \vbh ~ (G\mbh / 2 R)^{1/2} for the effect of a central
black hole of mass \mbh on gas at distance R and (c) v_{s} =(GM_h/ 2Cr_s)^{1/2}
which is closely related to the galaxy circular velocity, with C as a function
of halo concentration parameter. We find the wind terminal speed to be 2
(v_star^2 +1.5(\Gamma -1) \vbh^2 -v_s^2)^{1/2}, where \Gamma is the ratio of
force due to radiation pressure to gravity of the central black hole. We also
find that: (a) winds from quiescent star forming galaxies cannot escape from
10^{11.5} \le M_h \le 10^{12.5}Msun galaxies, (b) circumgalactic gas at large
distances should be present for galaxies in this mass range, (c) for an
escaping wind, the wind speed in low to intermediate mass galaxies is ~
400--1000 km/s, consistent with observed X-ray temperatures; (d) winds from
massive galaxies with AGN have speeds \gtrsim 1000 km/s. We also find that the
ratio [2 v_star ^2 -(1 -\Gamma) \vbh^2]/ v_c^2 dictates the amount of gas lost.
Used in conjunction with an appropriate relation between \mbh and M_h, and an
appropriate opacity of dust grains in IR (K band), this ratio becomes minimum
at a certain halo mass scale (M_h ~ 10^{12--12.5} Msun) that signifies the
cross-over of AGN domination in outflow properties from starburst activity at
lower masses. We find that stellar mass for massive galaxies scales as M_star
\propto M_h^{0.26},and for low mass galaxies, M_star \propto M_h^{5/3}.
