Supernovae and the Galactic Ecosystem

Wang, Q. Daniel

doi:10.1017/s1743921313009587

“…1 show a fully developed superbubble; it is impossible to make out individual SN remnants. Since most stars form in clusters, individual SN remnants are an exception rather than a norm (e.g., see Wang 2014). Most superbubble volume is overpressured (albeit slightly) relative to the ISM.…”

Section: The Fiducial Runmentioning

confidence: 99%

How multiple supernovae overlap to form superbubbles

Yadav

¹

,

Mukherjee

²

,

Sharma

³

et al. 2016

Mon. Not. R. Astron. Soc.

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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. 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 ∼ 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 (η mech ∝ n −2/3 g0 ). 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. We show that the mechanical efficiency increases with increasing resolution, and that explicit diffusion is required to obtain converged results.

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“…In this context Dorfi and Breitschwerdt (2012) suggested a model which can explain the power-law distribution of CRs between the "knee" and the "ankle". The impact of supernovae in superbubbles on the galactic ecosystem was discussed in various aspects by Hennebelle and Iffrig (2014) and by Wang (2014). One should have in mind the existence of a feedback effect of supernova and superbubbles on the global galactic ecology.…”

Section: Hydrodynamical Models Of Massive Star Winds and Superbubblesmentioning

confidence: 99%

Nonthermal particles and photons in starburst regions and superbubbles

Bykov

¹

2014

Astron Astrophys Rev

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Starforming factories in galaxies produce compact clusters and loose associations of young massive stars. Fast radiation-driven winds and supernovae input their huge kinetic power into the interstellar medium in the form of highly supersonic and superalfvenic outflows. Apart from gas heating, collisionless relaxation of fast plasma outflows results in fluctuating magnetic fields and energetic particles. The energetic particles comprise a long-lived component which may contain a sizeable fraction of the kinetic energy released by the winds and supernova ejecta and thus modify the magnetohydrodynamic flows in the systems. We present a concise review of observational data and models of nonthermal emission from starburst galaxies, superbubbles, and compact clusters of massive stars. Efficient mechanisms of particle acceleration and amplification of fluctuating magnetic fields with a wide dynamical range in starburst regions are discussed. Sources of cosmic rays, neutrinos and multi-wavelength nonthermal emission associated with starburst regions including potential galactic "PeVatrons" are reviewed in the global galactic ecology context.

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“…In this context Dorfi and Breitschwerdt (2012) suggested a model which can explain the power-law distribution of CRs between the "knee" and the "ankle". The impact of supernovae in superbubbles on the galactic ecosystem was discussed in various aspects by Hennebelle and Iffrig (2014) and by Wang (2014). One should have in mind the existence of a feedback effect of supernova and superbubbles on the global galactic ecology.…”

Section: Hydrodynamical Models Of Massive Star Winds and Superbubblesmentioning

confidence: 99%

Nonthermal particles and photons in starburst regions and superbubbles

Bykov

2015

Preprint

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Starforming factories in galaxies produce compact clusters and loose associations of young massive stars. Fast radiation-driven winds and supernovae input their huge kinetic power into the interstellar medium in the form of highly supersonic and superalfvenic outflows. Apart from gas heating, collisionless relaxation of fast plasma outflows results in fluctuating magnetic fields and energetic particles. The energetic particles comprise a long-lived component which may contain a sizeable fraction of the kinetic energy released by the winds and supernova ejecta and thus modify the magnetohydrodynamic flows in the systems. We present a concise review of observational data and models of nonthermal emission from starburst galaxies, superbubbles, and compact clusters of massive stars. Efficient mechanisms of particle acceleration and amplification of fluctuating magnetic fields with a wide dynamical range in starburst regions are discussed. Sources of cosmic rays, neutrinos and multi-wavelength nonthermal emission associated with starburst regions including potential galactic "PeVatrons" are reviewed in the global galactic ecology context.

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Supernovae and the Galactic Ecosystem

Cited by 4 publications

References 36 publications

How multiple supernovae overlap to form superbubbles

How multiple supernovae overlap to form superbubbles

Nonthermal particles and photons in starburst regions and superbubbles

Nonthermal particles and photons in starburst regions and superbubbles

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