Sound waves excitation by jet-inflated bubbles in clusters of galaxies

Assaf Sternberg*, Noam Soker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


We show that repeated sound waves in the intracluster medium (ICM) can be excited by a single inflation episode of an opposite bubble pair. To reproduce this behaviour in numerical simulations, the bubbles should be inflated by jets, rather than being injected artificially as already full-blown bubbles. The multiple sound waves are excited by the motion of the bubble-ICM boundary that is caused by vortices inside the inflated bubbles and the backflow ('cocoon') of the ICM around the bubble. These sound waves form a structure that can account for the ripples observed in the Perseus cooling flow cluster. We inflate the bubbles using slow massive jets either with a very wide opening angle or that are narrow and precessing. The wide jets (or collimated fast winds) are slow in the sense that they are highly subrelativistic, vj ∼ 0.01c- 0.1c, and they are massive in the sense that the pair of bubbles carries back to the ICM a large fraction of the cooling mass, i.e. ∼1-50 M yr-1. We use a two-dimensional axisymmetric (referred to as 2.5D) hydrodynamical numerical code (vh-1).

Original languageEnglish
Pages (from-to)228-233
Number of pages6
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - May 2009


  • Cooling flows
  • Galaxies: clusters: general
  • Galaxies: jets

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