Abstract Details
| Name: Naveen Yadav Affiliation: IISc Conference ID: ASI2016_699 Title : Dynamics of Supernova Driven Supershells Authors and Co-Authors : Naveen Yadav, IISc Prateek Sharma, IISc Biman Nath, RRI Dipanjan Mukherjee, ANU Abstract Type : Oral Abstract Category : Stars, The Milky Way Galaxy and its neighbours Abstract : we explore formation of superbubbles through energy deposition by multiple supernovae in the surrounding medium. We use total energy conserving 3-D hydrodynamic simulations to study the dynamics and energetics of superbubble formation. We study the scenario in which all the supernovae are correlated in space and time, occurring within a cluster of finite radius and lifetime. While isolated supernovae fizzle out completely by $\sim 1$ Myr, for a realistic cluster size it is likely that subsequent supernovae go off within the bubble and sustain the shock till the cluster lifetime, $\sim 30$ Myr, similar to the galactic dynamical timescale. We scan the parameter space of ISM density ($n_{\rm g}$), number of supernovae ($N_{\rm OB}$), and star cluster radius ($r_{\rm cl}$) to study the conditions for the formation of an over-pressured (super)bubble. For realistic cluster sizes, we find that the bubble remains over-pressured only if, for a given $n_{\rm g}$, $N_{\rm OB}$ is sufficiently large. While most of the input energy is still lost radiatively, superbubbles can retain up to $\sim 30\%$ of the input energy for several 10s of Myr. We find that radiative losses are enhanced (by $\approx 2$) in realistic 3-D simulations as compared to 1-D because of crinkling of radiative boundary layers. We compare the radius and velocity evolution of our shell with classic models and observations. We also confirm that a sufficiently large ($\gtrsim 10^4$) number of supernovae are required to go off in order to create a steady wind within the superbubble. We also briefly assess the influence of ISM density fluctuations on our results. |