Polarization observations of the hot-spot Pictor A West: shocks in backflows?
We present optical polarization maps of the western hot-spot of the radio galaxy Pictor A. We confirm the presence of optical emission in a bar-shaped structure extending over 24 arcsec perpendicular to the jet direction upstream of the hot-spot. We find its optical emission to be highly polarized w...
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| Format: | Conference item |
| Published: |
2002
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| Summary: | We present optical polarization maps of the western hot-spot of the radio galaxy Pictor A. We confirm the presence of optical emission in a bar-shaped structure extending over 24 arcsec perpendicular to the jet direction upstream of the hot-spot. We find its optical emission to be highly polarized with magnetic vectors being aligned perpendicular to the jet axis. From the high degree of polaxization we infer that the extended optical emission is of synchrotron origin. Radiative lifetimes of electrons emitting synchrotron emission at frequencies as high as 10(14) Hz are much shorter than diffusion time scales of particles accelerated within a narrow jet. Among different ways. to account for local acceleration of these electrons, we favour a scenario explaining the extended bar-shaped region as a shock-front in the back-flow of the radio-jet. |
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