1. Using AGN as Probes of the ICM
Minnesota Institute of Astrophysics
Using AGN as Probes of the ICM
Peter Mendygral1,2 Tom Jones1, Klaus Dolag3
1University of Minnesota – Minnesota Supercomputing Institute
2 Cray Inc.
3Max Planck Institute for Astrophysics
Simulations run on Itasca at MSI, Harvard ITC cluster (thanks to Paul Edmon) and Kraken
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ICM Theory and Computation

2. ICM Theory and Computation
Basic Questions
What effect does ICM weather have on the AGN outflow – ICM interaction?
Looking at “relaxed” cluster
How do those effects change with different AGN plasma β?
How do synthetic observations of these models compare with real observations?
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ICM Theory and Computation

3. Simulation Description
Similar to Morsony et al. (2010) prescription
Simulations initialized with output from MHD Gadget3 cosmological simulation
AGN simulations performed with WOMBAT code (Mendygral et al. in prep)
10083 kpc3 box with Δx = 1 kpc
Static potential with total energy conserving method
No radiative cooling
Passive CR electrons from γ = 10 – 1.6x105 with CGMV method (Jones & Kang 2005)
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ICM Theory and Computation

4. ICM Theory and Computation
Cluster Description
1.53x1014 M
Rvirial = 1.4 Mpc
7 Gyr since last major merger
“Relaxed” with an X-ray concentration parameter c = 0.66
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ICM Theory and Computation

5. ICM Theory and Computation
Cluster Winds
ICM wind across jet axis
~400 km s-1
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ICM Theory and Computation

6. ICM Theory and Computation
Bidirectional Jets
Jets launched from cluster center
Toroidal magnetic field
<ρICM>/ρjet ~ 200
Pjet ~ <PICM>
βjet = 100, 10, 1 (corresponding to 8 μG, 25 μG, 80 μ)
vjet/cs,ICM ~ Mach 18 (internal Mach 1.2) ~ 0.04c
Ljets = 6x1044 erg s-1
Duty cycle corresponding to 26 Myr period (6 cycles + 50 Myr off)
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ICM Theory and Computation

7. ICM Theory and Computation
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ICM Theory and Computation

8. ICM Theory and Computation
Morphologies
β = 10
β = 1
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ICM Theory and Computation

9. ICM Theory and Computation
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ICM Theory and Computation

10. Field Lines on Edges of Lobes
β = Myr
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ICM Theory and Computation

11. Average Field Strength in Lobes
β = 10
β = 1
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ICM Theory and Computation

12. ICM Theory and Computation
β = 100
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ICM Theory and Computation

13. ICM Theory and Computation
209 Myr
β = 10
β = 1
178 MHz
178 MHz
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ICM Theory and Computation

14. ICM Theory and Computation
209 Myr
β = 10
β = 1
300 MHz
300 MHz
1.4 GHz
1.4 GHz
100 kpc
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ICM Theory and Computation

15. ICM Theory and Computation
WAT / Double-double
β = 100 at 178 MHz
in Abell 1446 at 4.86 GHz
J at 334 MHz
Image Credit: Machalski et al. 2010, A&A, 510, A84
Image Credit: Jetha et al. 2006, MNRAS, 368, 609
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ICM Theory and Computation

16. ICM Theory and Computation
Resolution Study
144 Myr
20003 box with Δx = 0.5 kpc
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ICM Theory and Computation

17. ICM Theory and Computation
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ICM Theory and Computation

18. ICM Theory and Computation
Conclusions
“Relaxed” cluster may still contain significant weather. In these simulations these flows were enough to deflect jets.
Deflections are consistent with a simple calculation of ICM wind accelerating the cocoon.
Independent on AGN plasma β.
Intermittency in the presence of ICM wind results in mixing in the lobes. It also produces rounder X-ray cavities when compared to steady jets (e.g., O’Neill & Jones 2010).
Intermittency of jets produces radio morphology resembling double-doubles
Lobe deflections resemble WATs
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ICM Theory and Computation

19. ICM Theory and Computation
RM Analysis
See Andrew Johnson’s poster on an analysis of the RM structures from these simulations
To get to the poster go by the food.
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ICM Theory and Computation