Radio and X-Ray Observations of the Jet in Centaurus A

By M. Hardcastle, D. Worrall, R. Kraft, W. Forman, C. Jones, S. Murray. 2003

194 citations recorded by the source corpus.

We present new, high dynamic range VLA images of the inner jet of the closest radio galaxy, Centaurus A. Over a 10 yr baseline we detect apparent subluminal motions (v ~ 0.5c) in the jet on scales of hundreds of parsecs. The inferred speeds are larger than those previously determined using VLBI on smaller scales and provide new constraints on the angle made by the jet to the line of sight if we assume jet-counterjet symmetry. The new images also allow us to detect faint radio counterparts to a number of previously unidentified X-ray knots in the inner part of the jet and counterjet, showing conclusively that these X-ray features are genuinely associated with the outflow. However, we find that the knots with the highest X-ray/radio flux density ratios do not have detectable proper motions, suggesting that they may be related to standing shocks in the jet; we consider some possible internal obstacles that the jet may encounter. Using new, high-resolution Chandra data, we discuss the radio to X-ray spectra of the jet and the discrete features that it contains, and we argue that the compact radio and X-ray knots are privileged sites for the in situ particle acceleration that must be taking place throughout the jet. We show that the offsets observed between the peaks of the radio and X-ray emission at several places in the Cen A jet are not compatible with the simplest possible models involving particle acceleration and downstream advection together with synchrotron and expansion losses.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c308d6807f2a54c2e8fc8b915b15d426eef1c5f6

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In Astronomy and Astrophysics

1. E. Orlando
2. Troy A. Porter
3. A. Reimer
4. Igor V. Moskalenko
5. J. Finke
6. C. Dermer
7. G. Jóhannesson
8. Bing Zhang

In Nuclear and High Energy Physics

1. E. Orlando
2. Troy A. Porter
3. A. Reimer
4. I. Grenier
5. C. Dermer
6. Igor V. Moskalenko
7. J. Finke
8. G. Jóhannesson

Citations in the corpus

• FERMI LARGE AREA TELESCOPE VIEW OF THE CORE OF THE RADIO GALAXY CENTAURUS A (2010, background): “A strong, well-collimated jet can be seen on the arcsecond size scale in the radio,119 and Chandra can resolve X-ray emission from it, which is likely caused by synchrotron emission120 (Kraft et al. 2002; Hardcastle et al. 2003).”
• X-Ray Emission from Extragalactic Jets (2006, background): “…(2002); 9 Zezas et al. (2005); 10 Chiaberge et al. (2003); 11 Harris et al. (2002); 12 Wilson & Yang (2002); 13 Marshall et al. (2002); 14 Hardcastle et al. (2003); 15 Marshall et al. (2005); 16 Hardcastle et al. (2005); 17 Evans et al. (2005); 18 Worrall & Birkinshaw (2005); 19 Pesce et…”