Insights on jet physics high energy emission processes from optical polarimetry
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Insights on Jet Physics & High-Energy Emission Processes from Optical Polarimetry. Eric S. Perlman Florida Institute of Technology Collaborators: C. A. Padgett, M. Georganopoulos (UMBC), F. Dulwich, D. M. Worrall, M. Birkinshaw (Bristol),

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Insights on Jet Physics & High-Energy Emission Processes from Optical Polarimetry

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Insights on jet physics high energy emission processes from optical polarimetry

Insights on Jet Physics & High-Energy Emission Processes from Optical Polarimetry

Eric S. Perlman

Florida Institute of Technology

Collaborators: C. A. Padgett, M. Georganopoulos (UMBC),

F. Dulwich, D. M. Worrall, M. Birkinshaw (Bristol),

A. S. Wilson (UMCP), W. B. Sparks, J. A. Biretta (STScI),

C. O’Dea, S. Baum (RIT) + several others…


Radiation processes in jets

Radiation Processes in Jets

e-

B

Jet “beam”

Inverse-Compton – scattering interaction between photon and a relativistic particle that results in a higher-energy photon.

Synchrotron radiation emitted by relativistic particles in magnetic field

Radiation from jets emitted by two processes: synchrotron and inverse-Compton.

For inverse-Compton, the ‘scattered’ photon can be either from within the jet (often called synchrotron self-Compton) or some external source (e.g, the cosmic microwave background or emission line regions).

Important questions:

What does the magnetic field configuration look like?

Does it change as one goes up in energy?

What clues can the magnetic field configuration and ordering give us to radiation and physical mechanisms involved in producing high-energy emissions?


Insights on jet physics high energy emission processes from optical polarimetry

Perlman et al. 1999


Insights on jet physics high energy emission processes from optical polarimetry

Comparing jet width in

Radio, optical, X-rays…

X-ray jet is narrowest

Optical jet is next

Radio jet is widest


Insights on jet physics high energy emission processes from optical polarimetry

Perlman & Wilson 2005


Insights on jet physics high energy emission processes from optical polarimetry

Stratified jet…

High energy particles nearer jet axis

Low energy particles evenly distributed

B gets compressed, becomes  to jet in shocks inside jet

Shocks accelerate particles, so they brighten optical emission but not radio

Further development of magnetic field depends on two scale lengths:

Magnetic field coherence length lB

Synchrotron cooling length lcool

Perlman et al. 1999

lB = lcoolPerlman, Georganopoulos & Kazanas, in progresslB=2lcool


Insights on jet physics high energy emission processes from optical polarimetry

3C15

Optical and radio jet roughly similar but optical jet narrower

2 knots in X-ray, one coincident with knot C, the other not coincident with radio/opt (A’)

Knot A’ X-ray max corresponds to a feature seen in UV but not in any other r/o band


3c 15

3C 15

  • Polarimetry differences more subtle than M87

  • In all X-ray maxima, there are interesting radio-optical polzn differences in the neighborhood

    • Resolution marginal

  • Optical spectrum hardens too

  • But still indicate stratification

    • 2-component plasma, relativistic spine, slower sheath

    • Knot C is a torsional compression of the jet where X-ray emission is triggered


3c 264

3C 264

  • Wide-angle tail type source.

  • Bend about 4” from nucleus

  • Optical emission dims markedly after 1”

  • X-ray emission both from inner jet as well as optically fainter outer jet


3c 2641

3C 264

  • Resolution of Chandra data too low to firmly associate inner jet X-ray emission with optical feature

    • But polarization anomalies at 0.8” from nuclueus, just up-stream of “ring”

  • Outer jet emission -- optically faint, hard to tell


3c 346

3C 346

  • Kinked jet seen in both radio and optical

  • Major bend may be the result of the passage of a companion galaxy

  • X-ray emission from ~0.3” before kink

  • Major change in polarization characteristics near kink


3c 3461

3C 346

  • Increase in polarization near X-ray maximum.

  • Small rotation in position angles, only in optical, at that point.

  • Hardening of optical spectrum at X-ray max.

  • Synchrotron X-ray emission with associated compression?


3c 371

3C 371


3c 3711

3C 371

  • Optical shows low polarization in 2 X-ray maxima, high polarization in one.

  • Significant rotations seen in optical also

    • Neither is seen in radio


Summary

Summary

  • In all cases, *something* happens in polarimetry at loci of X-ray emission

  • What happens appears different in each jet and each component

  • Usually associated with an increase in radio-optical polarimetry differences

  • Optical spectrum seems to harden at X-ray flux max

  • X-ray emission from only a small part of jet “cross-section”

  • Optical Polarimetry can serve as a diagnostic for X-ray emission mechanism

  • This is crying out to be done for higher-power jets!


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