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How multiple supernovae overlap to form superbubbles

Yadav, Naveen and Mukherjee, Dipanjan and Sharma, Prateek and Nath, Biman B (2017) How multiple supernovae overlap to form superbubbles. In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 465 (2). pp. 1720-1740.

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Official URL: http://dx.doi.org/10.1093/mnras/stw2522


We explore the formation of superbubbles through energy deposition by multiple supernovae (SNe) in a uniform medium. We use the total energy conserving, 3D hydrodynamic simulations to study how SNe correlated in space and time create superbubbles. While isolated SNe fizzle out completely by similar to 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. For realistic cluster sizes, we find that the bubble remains overpressured only if, for a given n(g)0, NOB is sufficiently large. While most of the input energy is still lost radiatively, superbubbles can retain up to similar to 5-10 per cent of the input energy in the form of kinetic+thermal energy till 10 Myr for interstellar medium density n(g)0 approximate to 1 cm(-3). We find that the mechanical efficiency decreases for higher densities (eta(mech) alpha 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 less than or similar to 10 per cent of the injected energy, thereby explaining the observed smaller size and slower expansion of supershells. We also confirm that a sufficiently large (greater than or similar to 10(4)) number of SNe are required to go off in order to create a steady wind with a stable termination shock within the superbubble. We show that the mechanical efficiency increases with increasing resolution, and that explicit diffusion is required to obtain converged results.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the OXFORD UNIV PRESS, GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND
Department/Centre: Division of Physical & Mathematical Sciences > Joint Astronomy Programme
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 03 Apr 2017 04:47
Last Modified: 03 Apr 2017 04:47
URI: http://eprints.iisc.ac.in/id/eprint/56442

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