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Multi - l emission from large-scale jets

Multi - l emission from large-scale jets. Fabrizio Tavecchio. INAF – Osservatorio Astronomico di Brera. Outline. Introduction X-rays from radiogalaxies: synchrotron from HE electrons X-ray jets in QSO: the IC/CMB model Recent observations Criticisms, alternatives.

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Multi - l emission from large-scale jets

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  1. Multi-lemission from large-scale jets Fabrizio Tavecchio INAF – Osservatorio Astronomico di Brera

  2. Outline Introduction X-rays from radiogalaxies: synchrotron from HE electrons X-ray jets in QSO: the IC/CMB model Recent observations Criticisms, alternatives

  3. Almost every galaxy hosts a BH 99 % are silent 1 % are active 0.1% have jets

  4. Relativistic jets: channels transporting Mass Momentum Energy from the central BH to the IGM lobes core Hot spots Cygnus A

  5. The unification scheme: blazar radiogalaxy, RL QSOs

  6. Jets: from the BH to large scale Resolved X-ray jet VLBI region Blazar emission region Accretion region

  7. X-rays: a new window on old problems Acceleration and collimation Power, composition Particle acceleration …

  8. 1127-145 Siemiginowska et al. 2001 PKS 0637-752 Chartas et al. 2000 Pic A Wilson et al. 2000 Cen A Hardcastle et al. 2003

  9. Synchrotron SSC thermal Schwartz et al. 2000 Radiogalaxies FRIs: Synchrotron e.g Worrall et al. 2001, 2002 FRIIs: Synch? SSC? e.g Wilson et al. 2001 Producing X-rays in large-scale jets Powerful (aligned) QSOs IC/CMB Tavecchio et al. 2000 Celotti et al. 2001 very energetic electrons

  10. 3C371: a synchrotron jet ge~107 Knot B Pesce et al. 2001 Knot A

  11. M87 X-rays radio optical

  12. Radiogalaxies (FRI): Very high-energy electrons (ge~107) injected in-situ within the jet (shocks? reconnection?)

  13. Powerful QSOs

  14. IC/CMB Synchrotron g~100 G=5-10 at >100 kpc

  15. Amplification of the CMB energy density U’~U G2 G=10 Photons will appear more concentrated in time and with an energye1=e G

  16. Amplification of the emission L’=1 G=10 L=160,000 d = [G(1-b cos q)]-1 L=10-4 L=3x10-3

  17. IC with CMB (radio and X-rays) d~10 Equipartition (radio) small q~5 deg G~10 Parameter space

  18. A Chandra-HST survey of jets IC/CMB knots 17 “radio selected” jets 10 with X-rays (59%) 10 with optical Sambruna et al. 2001 Sambruna et al. 2004

  19. Deep images 1136-135 1150+497

  20. Synchrotron to Compton transition?

  21. Speed and power The model allows us to constrain the physical parameters of jets at kpc scale G~3-10 P~1047 -1048 erg/s Supported by recent numerical simulations (Scheck et al. 2002), but see Wardle & Aaron 1997 Fast spine? (Chiaberge et al. 2000; Celotti et al. 2001)

  22. Problems, criticisms, alternatives Cooling: why X-ray knots? Large power requirements (~1048 erg/s) Close alignement (small prob.)

  23. Tavecchio, Ghisellini & Celotti 2003 Clumps in jets? Problem: the X-ray emitting electrons cannot cool inside the knot even including adiabatic losses!

  24. expansion very efficient adiabatic losses A possible solution Several compact regions overpressured with respect to the external plasma (instabilities, clouds, entrained material, reconnection sites) Consequence: expected variability in knots (~month)

  25. Several knots in M87 are variable! (Harris et al. 2003) Cen A shows compact X-ray/radio knots (Hardcastle et al. 2003) New evidences:

  26. Alternatives to the IC/CMB: Synchrotron from complex electron distributions:

  27. From cooling… g~107 - 108 cooled electrons uncooled electrons Dermer & Atoyan 2002

  28. …or from acceleration Multiple shocks or turbulence (Stawarz et al. 2004): Marcovith & Kirk 1999

  29. Synchrotron from another electron component or from HE protons… Aharonian 2002

  30. inefficient, Urad quite small a density of ~1 part/cm3 is necessary Secondary electrons could be produced through p-g or p-p Aharonian 2002

  31. Summary Radiogalaxies: a unique synchrotron component from radio to X-rays – acceleration mechanism? The IC/CMB model works well for powerful jets in QSO Deep pointings reveal synchrotron to IC transition along the jet BUT: problems with low E electrons: clumps? More observations and exploration of alternatives…

  32. From subpc to kpc-scale Blazars and Chandra: physical quantities at (very) different scales! Example: 1510-089 (z=0.361) 16 -5 22 B=2G; R=3x10 cm B=0.6x10 G; R=2x10 cm

  33. Problems, criticisms, alternatives Cooling: how to produce X-ray knots? Large power requirements (~1048 erg/s) Close alignement (small prob.) Global behaviour (but see G&K 2003) {

  34. Layer and spine

  35. M87

  36. PKS1127-145Siemiginowska et al. 2002 Offsets?

  37. Evidences for small angles from superluminal motions: Lorentz factor Angle

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