Astron. Astrophys. 361, 529-534 (2000)

4C 39.25: Witnessing the interaction between a moving and a stationary component

A. Alberdi ¹, J.L. Gómez ¹, J.M. Marcaide ², A.P. Marscher ³ and M.A. Pérez-Torres <sup>2,4

1</sup> Instituto de Astrofísica de Andalucía (CSIC), Apartado 3004, 18080 Granada, Spain
² Departamento de Astronomía, Universitat de València, 46100 Burjassot, Spain
³ Department of Astronomy, Boston University, Boston MA 02215, USA
⁴ Present address: Istituto di Radioastronomia (CNR), 40129 Bologna, Italy

Received 23 May 2000 / Accepted 7 July 2000

Abstract

We present multi-epoch multi-frequency VLBI images of the compact polarized radio structure of the quasar 4C 39.25. Between 1995 and 1999, the total intensity images at 15, 22, and 43 GHz have remained almost unperturbed, while there have been significant changes in the polarized intensity maps together with a related rotation of the polarization angle. These changes in the polarized structure trace in great detail the interaction between a moving and a standing component. We interpret the stationary feature as a bend in the jet trajectory in a plane that does not contain the observer, and the moving one as a shock turning around the bend.

Key words: galaxies: individual: 4C 39.25 galaxies: active galaxies: jets radio continuum: galaxies

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Contents

• 1. Introduction
• 2. Observations and data reduction
• 3. Results
  • 3.1. Total intensity images
  • 3.2. Polarization images
• 4. Discussion
• 5. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: October 2, 2000
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