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

Explore self-consistent acceleration and transport of cosmic ray electrons in 3D MHD jet simulations. Learn how synthetic observations provide insights into dynamics, field properties, and energy partitioning. Discover the benefits of combined radio and X-ray observations in understanding extragalactic jets.

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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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