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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 - PowerPoint PPT Presentation
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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 ConnectionsFebruary 5, 2004
Overview
Introduction: A new approach Background: The simulations Opportunities: Synthetic Observations
– What, Why, How?
Insights– Dynamics– Field properties– Energy partitioning
Conclusion: Opportunities
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?
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
p
pq
pf
i
i
q
n
i
i
iii
2/1
2/113
4
33
2/12/1
2
3
1
3 q
r
rq
2/1
2/1|3
023
14
i
i
pp
s
i fpp
p
p
qDu
dt
dn
One Jet…(Tregillis et al. ApJ, 557, 475)
Light, supersonic (nonrelativistic) 3D MHD jet Mj=8, =j/a=0.01; pressure matched in
uniform background Helical magnetic field; 0 = 100 on axis Symmetry broken with 5o precession 15 zones across jet core for accurate shock
identification
…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 (=10-4) of thermal electron flux “injected” at shocks
Model 3: “Cooling”– Radiative lifetime for 5 GeV electrons ~ simulation duration– Spectra experience considerable aging
Particles…
…and Fields
Synthetic Observations
Particles
+ j
Fields
Synthetically-observable quantities include:Radio synchrotron surface brightness and spectral indexIC/3K and SSC X-ray surface brightnessRadio polarimetry (Stokes Q, U); Faraday rotation & RM
Example:Radio Surface Brightness, 1.4 GHz
Injection Cooling
Combined Observations (finally):Dynamical Insights(Tregillis et al. ApJ February 1, 2004)
IIC/3K ISm ; m = 1/3 – 1/2
Is neDB1+~ 0.5 - 1.0IIC/3K neD B ne
b
Compression (tangled) : B 2/3 m ~ 0.5 – 0.43Perpendicular shocks: B m ~ 0.4 – 0.33
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: IS m ~ 1.47 ( ~ 0.65)
Combined Observations:Magnetic Field Strengths
)(
)(1009.21006.11
14113
0
01
xic
rs
x
r
a
BC
ic I
Iz
j
jB
7/22/1
12/1
2
0
02/3
35
2/1
)(
sin
)1(11069.5
F
l
zkB
yxme
Radio:
Radio & X-ray:
The Gritty Reality…
…and Derived Values
Combined Observations:Energy Partitioning
kdB
Bd
U
Ud
meE
B
1
4
3; min
2/7
min
•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?
Best Case Scenario: High Degree of Uniformity
d Control Injection Cooling
Initial Conditions
1.6 x 10-1 1.6 x 103 1.6 x 10-1
Derived from Bic and Bme
1.7 x 10-1 1.2 x 103 9.2 x 10-2
We know d exactly at the base of the jet…
More Gritty Reality
…and More Derived Values
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.