Non-equilibrium ionization and radiative transport in an evolving supernova remnant

Kartick C. Sarkar*, Orly Gnat, Amiel Sternberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We present numerical simulations of the evolution of a supernova (SN) remnant expanding into a uniform background medium with density n H = 1.0\,\cm-3 and temperature of 104 K. We include a dynamically evolving non-equilibrium ionization (NEI) network (consisting of all the ions of H, He, C, N, O, Ne, Mg, Si, S, Fe), frequency dependent radiation transfer (RT), thermal conduction, and a simple dust evolution model, all intra-coupled to each other and to the hydrodynamics. We assume spherical symmetry. Photoionization, radiation losses, photo-heating, charge-exchange heating/cooling, and radiation pressure are calculated on the fly depending on the local radiation field and ion fractions. We find that the dynamics and energetics (but not the emission spectra) of the SN remnants can be well modelled by collisional equilibrium cooling curves even in the absence of non-equilibrium cooling and radiative transport. We find that the effect of precursor ionizing radiation at different stages of SN remnant are dominated by rapid cooling of the shock and differ from steady-state shocks. The predicted column densities of different ions such as N+, C3+, and N4+, can be higher by up to several orders of magnitude compared to steady-state shocks. We also present some high-resolution emission spectra that can be compared with the observed remnants to obtain important information about the physical and chemical states of the remnant, as well as constrain the background interstellar medium.

Original languageAmerican English
Pages (from-to)583-600
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - 1 Jun 2021

Bibliographical note

Publisher Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.


  • H ii regions
  • ISM: bubbles
  • ISM: supernova remnants
  • hydrodynamics
  • methods: numerical
  • radiative transfer


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