1. The luminous X-ray hotspot in 4C 74.26: jet dynamics at work Mary Erlund Institute of Astronomy, Cambridge, UK A.C. Fabian, K.M. Blundell, C. Moss and D.R. Ballantyne &

2. Grey-scale: 1.47 GHz radio data from VLA B-array 4C 74.26 z=0.104 Largest known radio quasar 10' on sky (1.1 Mpc) ‏ deprojected length (45 deg) at least 1.6Mpc

3. Green contours: - XMM EPIC-pn data - 0.5-10 keV band - 34 ks observation Southern side of 4C 74.26 Grey-scale: - 1.47 GHz radio - VLA B-array

4. Hotspot offset Grey-scale: - Chandra data - 0.5-7keV band - ~70ks with grating

5. Hotspot offset Grey-scale: - Chandra data - 0.5-7keV band - ~70ks with grating Blue contours: - VLA B array at 1.47GHz - 5.1” resolution

6. Hotspot offset Grey-scale: - Chandra data - 0.5-7keV band - ~70ks with grating Blue contours: - VLA B array at 1.47GHz - 5.1” resolution Red contours: - VLA A array at 1.49GHz - 1.7” resolution

7. Hotspot offset Grey-scale: - Chandra data - 0.5-7keV band - ~70ks with grating Blue contours: - VLA B array at 1.47GHz - 5.1” resolution Red contours: - VLA A array at 1.49GHz - 1.7” resolution Magenta contours: - MERLIN at 1.66GHz - 0.2” resolution

8. Hotspot profile black line: - Chandra - 0.5-7keV band - Gaussian- smoothed so 1.5” resolution red line: - VLA A array - 1.49GHz - 1.7” resolution magenta line: - MERLIN - 1.66GHz - 0.2” resolution

9. Background AGN?

10. Image: - optical data - R = 24.3mag limit. White contours; - VLA B-array Yellow circle: - radius 3 arcsec - X-ray hotspot

11. Constraints from optical data X-ray to optical flux ratio: X/O > 120 Typical Type I AGN: X/O <10 Extreme X-ray / optical (EXO) AGN (very rare): X/O ~ 100 If an EXO it is much more X-ray bright than any detected X-ray spectrum not that of an EXO

12. Luminous X-ray hotspot 4C 74.26:L X(0.5-10keV) ~ 2.2 x 10 42 ergs -1 Pictor A: L X(0.5-10keV) ~ 1.6 x 10 42 ergs -1 Cygnus A: L X(0.5-10keV) ~ 1.8 x 10 42 ergs -1 (Wilson et al. 2001, Wilson et al. 2000) ‏ Photon index, Г = 1.54 +/- 0.1 (i.e. Spectral index, α = 0.54 +/- 0.1) ‏ consistent with: - other hotspots and - models of shock acceleration (Heavens & Drury 1988; Achterberg et al. 2001) ‏

13. Models for X-ray / radio hotspot offset

14. Up-scattering of the CMB in a relativistic decelerating flow Georganopoulos & Kazanas 2004 Jet X-ray Radio CMB Core

15. Spine-sheath model e.g. Chiaberge et al. 2000 X-ray: spine Radio: sheath Slower but more massive sheath Faster but less massive spine core

16. Dentist’s drill model Scheuer 1982 X-ray: New Radio: Old Old jet path New jet path Core

17. Implications of relativistic jet models Relativistic decelerating flow and sheath model : Implies jet is relativistic (Γ~2) over extremely large distances (> 800kpc). Limitation of relativistic decelerating flow model : If the source was aligned closer to the line of sight, X-ray hotspot would be even brighter: it is already a very bright hotspot.

18. Conclusions The southern X-ray hotspot in 4C 74.26 is X-ray luminous The X-ray / radio offset is 10” or 19kpc projected onto the sky The models that can reproduce what we see have important consequences for jet dynamics In order to distinguish between them we need Chandra imaging of the hotspot complex and high quality optical data

19. Thank you