http://arxiv.org/abs/1401.5070
Heating of the interstellar medium by multiple supernovae (SNe) explosions is at the heart of producing galaxy-scale outflows in starburst galaxies. Standard models of outflows assume a high efficiency of SNe in heating the gas to X-ray emitting temperatures and to fill the central region of starburst with hot gas, in order to launch vigorous outflows. We study the efficiency of multiple SNe in heating the interstellar medium (ISM) and filling the volume with gas of high temperatures, with 2-D and 3-D hydrodynamic simulations. We argue that SNe have to be clustered in space and time (and be coherent) in order to compensate for the radiative loss. In particular, we find that in coherent cases, the filling factor of gas with $3 \times 10^6$ K can be at the most $\le 0.3$ and the total heating efficiency $\le 0.3$, for gas with density $1$ cm$^{-3}$ and $0.1\hbox{–}1$ Z$_\odot$. The heating efficiency and filling factors are much smaller in incoherent cases. Comparing our results to the commonly adopted efficiency ($0.1\hbox{–}0.3$) and large filling factor of hot gas in models of starburst driven galactic outflows, we therefore conclude that outflows can be driven by multiple SNe if the coherency condition is satisfied.
Wed, 22 Jan 14
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