inflating fat bubbles in clusters of galaxies by slow wide jets assaf sternberg (did the work) noam...
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Inflating Fat Bubbles in Clusters of Galaxies by Slow Wide Jets
Assaf Sternberg (did the work)
Noam Soker (speaker today)
Technion, Israel July 2008
Goal: To form ‘Fat’ Bubbles
PERSEUS IN VISIBLE AND X-RAY
Old bubble
Young bubbles
Rayleigh-Taylor instability
From Fabian and
collaborators
Cluster
Cluster
Planetary nebula
Planetary nebula
More ‘Fat’
Bubbles
From planetary nebulae we learn that there is no need for relativistic effects or strong magnetic fields
NGC 3587 Guerrero et al.
From Gorny et al .
NGC 2818
He 2-116.
NGC 3195 He 2-37.
Initial Setting
LowDensity
HighDensity
ICM in hydrostatic equilibrium
Wide Jet or
Precessing Jet
1
12
44 12
7
7750
10
2 10
2.7 10
j
j
j
v km s
M M yr
E erg s
T K
RESULTS: (1) Fat Bubbles (Assaf Sternberg PhD thesis)
The jet:
Temperature Density
44 1 1
1
10 ; 7750
5 ; 70
j j
Oj
E erg s v km s
M M yr
After 2.5 Myr
After 5 MyrAfter 5 Myr
Forward shock (ICM is
shocked)
Forward shock (ICM is
shocked)
Reverse shock (jet is shocked)
Contact discontinuity
RESULTS: (2a) Buoyant Bubbles
Evolution with gravity included. Here the density and velocity maps when the jet is shut off after10Myr activity.
Note 2: Vortex
Note 1: ICM Backflow
Note 3: a dense shell with momentum
During the inflation phase the bubble is stable (Pizzolato & Soker 2006)
Evolution of a bubble inserted by hand
After 15 Myr
After 30 Myr After 30 Myr
Jet-inflated bubble Artificial Bubble
Full evolution of ajet-inflated bubble
After 15 Myr
Instabilities
Momentum of shell leads to faster
motion
A weak shock
Note 4: mixing of hot gas with the ICM
Note 5: no instabilities
RESULTS (2b) Evolution
(Sternberg& Soker,MNRASLetter,in press)
Ripples in Perseus)Fabian et al(.
RESULTS: (3) Sound Waves: Wide jets
Density
Jets were active from to
A weak shock
Note 7: Several sound waves
0t 10t
Note 6: Complicated and changing bubbles’ shape
DensityJet was active at all times, starting at t=0.
Note 7: Several sound waves
RESULTS: (3) Sound Waves:
Precessing jets
A weak shock: Mach=1.3
SUMMARY
Slow massive jets can account for:
(1)Recycling of gas that cools from the ICM. (2) Formation of fat bubbles close to the center.(3) Allowing the bubble to rise to large distances. (4) Efficient energy transfer form bubbles to the ICM.
A realistic jet-inflation process shows that:
1) Vortices can stabilize the bubble.
2) The expanding shell around the bubble stabilizes it.
3) An efficient mixing between bubbles and the ICM.
4) One inflation episode excites several sound waves.