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Synthetic X-Ray and Radio Observations of Simulated Jets: Insights and Opportunities

Synthetic X-Ray and Radio Observations of Simulated Jets: Insights and Opportunities. I. L. Tregillis (LANL / U of MN) T. W. Jones (U of MN) Dongsu Ryu (Chungnam Natl. Univ.). X-ray and Radio Connections February 5, 2004. Overview. Introduction: A new approach

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Synthetic X-Ray and Radio Observations of Simulated Jets: Insights and Opportunities

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  1. Synthetic X-Ray and Radio Observations of Simulated Jets:Insights andOpportunities I. L. Tregillis (LANL / U of MN) T. W. Jones (U of MN) Dongsu Ryu (Chungnam Natl. Univ.) X-ray and Radio Connections February 5, 2004

  2. Overview • Introduction: A new approach • Background: The simulations • Opportunities: Synthetic Observations • What, Why, How? • Insights • Dynamics • Field properties • Energy partitioning • Conclusion: Opportunities

  3. Introduction: A New Approach • Self-consistent acceleration and transport of cosmic ray (CR) electrons within 3D MHD jet simulations • Synthetic synchrotron radio and inverse-Compton X-ray observations (IC/3K, SSC) • Standard observational analyses • Tregillis et al. ApJ, v601 n2 February 1 2004 • The fun part: • Do we recover accurate source properties?

  4. Our Approach to CR Transport(Jones et al. ApJ, 512, 105) • Physical scales for acceleration << dynamical scales • Broad electron distribution f(p) enables “finite volume” approach in momentum space: • Use test-particle model for fast Fermi acceleration at shocks • Solve kinetic equation for downstream transport

  5. One Jet…(Tregillis et al. ApJ, 557, 475) • Light, supersonic (nonrelativistic) 3D MHD jet • Mj=8, h=rj/ra=0.01; pressure matched in uniform background • Helical magnetic field; b0 = 100 on axis • Symmetry broken with 5o precession • 15 zones across jet core for accurate shock identification

  6. …Three Scenarios(Tregillis et al. ApJ, 557, 475) • Model 1: “Control” • No injection of fresh particles at shocks • Negligible radiative aging • Model 2: “Injection” • Minimal CR population carried down jet • Fraction (e=10-4) of thermal electron flux “injected” at shocks • Model 3: “Cooling” • Radiative lifetime for 5 GeV electrons ~ simulation duration • Spectra experience considerable aging

  7. Particles…

  8. …and Fields

  9. Synthetic Observations Particles +  j  Fields Synthetically-observable quantities include: Radio synchrotron surface brightness and spectral index IC/3K and SSC X-ray surface brightness Radio polarimetry (Stokes Q, U); Faraday rotation & RM

  10. Example:Radio Surface Brightness, 1.4 GHz Injection Cooling

  11. Combined Observations (finally):Dynamical Insights(Tregillis et al. ApJ February 1, 2004) IIC/3K ISm ; m = 1/3 – 1/2 Is  neDB1+a a ~ 0.5 - 1.0 IIC/3K  neD B  neb Compression (tangled) : B  r2/3  m ~ 0.5 – 0.43 Perpendicular shocks: B  r  m ~ 0.4 – 0.33

  12. Dynamical Insights, continued(Tregillis et al. ApJ February 1, 2004) ISSC ISm ; m = 1/3 – 1/2 ISSC ISm ; m = 1.0 – 1.5 Locally dominated radiation field: F IS  m ~ 1.47 (a ~ 0.65)

  13. Combined Observations:Magnetic Field Strengths Radio: Radio & X-ray:

  14. The Gritty Reality…

  15. …and Derived Values

  16. Combined Observations:Energy Partitioning • Bme is inferred from the radio emission • B is the true field value in the ideal case • So, if Bic is a useful estimator of B, why not… • Replace B with Bic and get a direct estimate of d?

  17. Best Case Scenario: High Degree of Uniformity We know d exactly at the base of the jet…

  18. More Gritty Reality

  19. …and More Derived Values

  20. Conclusions & Future Work Combined synthetic X-ray and radio observations of simulated jets reveal: • Dominant dynamical and transport effects • Good estimates for local field strengths • Direct, independent estimates for the energy partitioning All of this information is crucial groundwork for understanding the long-term evolution and dissipation of extragalactic jets on cosmological scales.

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