%0 Generic %1 yadav2016supernovae %A Yadav, Naveen %A Mukherjee, Dipanjan %A Sharma, Prateek %A Nath, Biman B. %D 2016 %K explosion simulations sn superbubbles %T Supernovae under microscope: how supernovae overlap to form superbubbles %U http://arxiv.org/abs/1603.00815 %X We explore the formation of superbubbles through energy deposition by multiple supernovae (SNe) in a uniform medium. We use total energy conserving, 3-D hydrodynamic simulations to study how SNe correlated in space and time create superbubbles. While isolated SNe fizzle out completely by $1$ Myr due to radiative losses, for a realistic cluster size it is likely that subsequent SNe go off within the hot/dilute bubble and sustain the shock till the cluster lifetime. We scan the parameter space of ISM density ($n_g0$), number of SNe ($N_OB$), and star cluster radius ($r_cl$) to study the conditions for the formation of an overpressured (super)bubble. For realistic cluster sizes, we find that the bubble remains overpressured only if, for a given $n_g0$, $N_OB$ is sufficiently large. While most of the input energy is still lost radiatively, superbubbles can retain up to $\sim 5-10\%$ of the input energy in form of kinetic+thermal energy till 10 Myr for ISM density $n_g0 1$ cm$^-3$. We find that the mechanical efficiency decreases for higher densities ($\eta_mech \propto n_g0^-2/3$). We compare the radii and velocities of simulated supershells with observations and the classical adiabatic model. Our simulations show that the superbubbles retain only $10\%$ of the injected energy, thereby explaining the observed smaller size and slower expansion of supershells. We also confirm that a sufficiently large ($10^4$) number of SNe is required to go off in order to create a steady wind with a stable termination shock within the superbubble.

@misc{yadav2016supernovae, abstract = {We explore the formation of superbubbles through energy deposition by multiple supernovae (SNe) in a uniform medium. We use total energy conserving, 3-D hydrodynamic simulations to study how SNe correlated in space and time create superbubbles. While isolated SNe fizzle out completely by $\sim 1$ Myr due to radiative losses, for a realistic cluster size it is likely that subsequent SNe go off within the hot/dilute bubble and sustain the shock till the cluster lifetime. We scan the parameter space of ISM density ($n_{g0}$), number of SNe ($N_{\rm OB}$), and star cluster radius ($r_{\rm cl}$) to study the conditions for the formation of an overpressured (super)bubble. For realistic cluster sizes, we find that the bubble remains overpressured only if, for a given $n_{g0}$, $N_{\rm OB}$ is sufficiently large. While most of the input energy is still lost radiatively, superbubbles can retain up to $\sim 5-10\%$ of the input energy in form of kinetic+thermal energy till 10 Myr for ISM density $n_{g0} \approx 1$ cm$^{-3}$. We find that the mechanical efficiency decreases for higher densities ($\eta_{\rm mech} \propto n_{g0}^{-2/3}$). We compare the radii and velocities of simulated supershells with observations and the classical adiabatic model. Our simulations show that the superbubbles retain only $\lesssim 10\%$ of the injected energy, thereby explaining the observed smaller size and slower expansion of supershells. We also confirm that a sufficiently large ($\gtrsim 10^4$) number of SNe is required to go off in order to create a steady wind with a stable termination shock within the superbubble.}, added-at = {2016-03-03T10:40:02.000+0100}, author = {Yadav, Naveen and Mukherjee, Dipanjan and Sharma, Prateek and Nath, Biman B.}, biburl = {https://www.bibsonomy.org/bibtex/2bf838daa9399a7ad3360b78fdf0939d5/miki}, description = {[1603.00815] Supernovae under microscope: how supernovae overlap to form superbubbles}, interhash = {a1ced8f8aa97537661f1767e4221df29}, intrahash = {bf838daa9399a7ad3360b78fdf0939d5}, keywords = {explosion simulations sn superbubbles}, note = {cite arxiv:1603.00815Comment: 18 pages, 2 tables and 19 figures, submitted to MNRAS, Comments are welcome}, timestamp = {2016-03-03T10:40:02.000+0100}, title = {Supernovae under microscope: how supernovae overlap to form superbubbles}, url = {http://arxiv.org/abs/1603.00815}, year = 2016 }