טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentMichael Refaelovich
SubjectChains of X-ray Deficient Bubbles as a Consequence of
Vortices Fragmentation
DepartmentDepartment of Physics
Supervisor Full Professor Soker Noam
Full Thesis textFull thesis text - English Version


Abstract

We show that a continuous jet with time-independent launching properties can inflate a chain of close and overlapping X-ray deficient bubbles.
Using the numerical code PLUTO and realistic galaxy cluster profile we run 2.5D (i.e. spherical coordinate system with cylindrical symmetry) hydrodynamic simulations and study the interaction of the jets with the intra-cluster medium (ICM).

We present and discuss the relevant physical processes and the model assumptions.A key process is vortex fragmentation due to several mechanisms, including vortex-shedding and Kelvin-Helmholtz (KH) instabilities.
We analyze the morphology of the flow and find the basic dependence of the morphology upon the model parameters by carrying out a parameter survey.

During the presentation we touch various issues related to performing and analyzing simulations of the type used in this work. 
We also compare continuous jet scenario to a multiple jet-launching scenario and present a way which enables to discriminate between the two observationally.
Our results can account for the structure of two opposite chains of close bubbles as observed in the galaxy cluster Hydra A.
Our results imply that the presence of multiple pairs of bubbles does not necessarily imply several jet-launching episodes. In addition, we show that since the cavities are jet-driven during most of their way, cavities age estimations based on buoyancy are overly estimated.
Since age estimations are crucial to understanding the energetics of cooling and heating in clusters, these findings might have implications to feedback mechanisms operating by jets.