Semiempirical limits on the thermal conductivity of intracluster gas

Laurence P. David, John P. Hughes, Wallace H. Tucker

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


A semiempirical method for establishing lower limits on the thermal conductivity of hot gas in clusters of galaxies is described. The method is based on the observation that the X-ray imaging data (e.g., Einstein IPC) for clusters are well described by the hydrostatic-isothermal β model, even for cooling flow clusters beyond about one core radius. In addition, there are strong indications that noncooling flow clusters (like the Coma Cluster) have a large central region (up to several core radii) of nearly constant gas temperature. This suggests that thermal conduction is an effective means of transporting and redistributing the thermal energy of the gas. This in turn has implications for the extent to which magnetic fields in the cluster are effective in reducing the thermal conductivity of the gas. We present time-dependent hydrodynamic simulations for the gas in the Coma Cluster under two separate evolutionary scenarios. One scenario assumes that the cluster potential is static and that the gas has an initial adiabatic distribution. The second scenario uses an evolving cluster potential. These models along with analytic results show that the thermal conductivity of the gas in the Coma Cluster cannot be less than 0.1 of full Spitzer conductivity. These models also show that high gas conductivity assists rather than hinders the development of radiative cooling in the central regions of clusters.

Original languageEnglish (US)
Pages (from-to)452-458
Number of pages7
JournalAstrophysical Journal
Issue number2
StatePublished - 1992
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Conduction
  • Cooling flows
  • Galaxies: clustering
  • Intergalactic medium


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