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Hydrodynamics of Small- Scale Jets: Observational aspects

Hydrodynamics of Small- Scale Jets: Observational aspects. Esko Valtaoja Tuorla Observatory, University of Turku, Finland Metsähovi Radio Observatory, Helsinki University of Technology. TUORLA-METSÄHOVI AGN GROUP : Talvikki Hovatta, Elina

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Hydrodynamics of Small- Scale Jets: Observational aspects

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  1. Hydrodynamics of Small- Scale Jets: Observational aspects Esko Valtaoja Tuorla Observatory, University of Turku, Finland Metsähovi Radio Observatory, Helsinki University of Technology TUORLA-METSÄHOVI AGN GROUP: Talvikki Hovatta, Elina Lindfors, Anne Lähteenmäki, Elina Nieppola, Pia-Maria Saloranta, Tuomas Savolainen, Ilona Torniainen, Merja Tornikoski, Kaj Wiik

  2. Meg Urry 2007: ”Luckily, nobody remembers what we said 25 years ago, and the old acetates have decayed.”

  3. NEED: basic GLOBAL and LOCAL parameters from observations as inputs to theory / simulations... ... which, in turn, should give predictions which observers can test GLOBAL: e.g., BH mass vs. jet speed? LOCAL: e.g., magnetic field strength along the jet?

  4. Qualitative • agreement • but need also • quantitative: • global and • local parameters • vs. simulated • parameters Aloy et al. 2003 Gómez et al. 2001

  5. VLBA with all frequencies and polarization... (Savolainen et al., 2006, 2007) LOCAL data!

  6. ...gives us local information along and transverse to the jet (which you cannot get from single and/or low frequency VLBI) magnetic field vs. distance electron energy density vs. distance + jet/mf structures, instabilities, nonrelativistic plasma, speeds, IC fluxes... SAVE VLBA BY USING ITS FULL POWER!

  7. Marscher & Gear shock-in-jet model (1985) (picture courtesy of Marc Türler)

  8. Ten years of 3C 279 cm-to-optical variations modelled as ”M & G” shocks in a jet (Lindfors et al., 2006, original code developed by Marc Türler)

  9. LOCAL data! VLBI: Savolainen et al. 2007 Lindfors et al. 2005, 2006: shock and jet component spectra (+ SSC spectra) from mf continuum monitoring and 3-D fit simultaneously to all data

  10. Exponential, sharp flares (Valtaoja et al. 1999) Theory and simulations: quite different flare shapes (Gomez et al. 1997) ... are we missing something crucial?

  11. Jorstad et al. 2001 Savolainen et al 2002 • VLBI components correspond to • TFD flares = shocks in the jet • strong gamma flares from the • same shocks far from BH/BLR • T0(mm) < T0(VLBI) • T0(mm), T0(VLBI) < T0(gamma) need more accurate timings for each: physics of the radio core! Lähteenmäki & Valtaoja 2003

  12. Average delay from TFD/VLBI zero epoch to strong gamma flares ~ 2 months = parsecs, so External Compton fails... radio core EC photons are here! radio gamma ...but the only alternative, synchrotron-self-Compton also fails (Lindfors et al. 2005, 2006) (Heh.)

  13. Blazar sequence? (Ghisellini et al. 1998) Most powerful sources have lowest synchrotron peak frequencies One-parameter (total power) family:

  14. ...but fuller samples destroy the sequence! Nieppola et al. 2006: 381 Northern Veron- Cetty&Veron BL Lacs, a ”complete” sample (also Giommi et al. 2005; Padovani 2007 + others)

  15. D(var) = [TB(var)/TB(lim)]1/3 (Lähteenmäki & Valtaoja 1999) Wu et al 2007:

  16. Correcting the luminosities for Doppler boosting totally destroys the last traces of the ”blazar sequence” (Saloranta, Nieppola, in preparation) (quasars) (BL Lacs)

  17. BH MASS as the fundamental parameter? (work in progress, Tuorla & Metsähovi): from spectroscopy and imaging BH MASS 2 main observables: L(peak) DOPPLER- n(peak) CORRECTED! 2 main jet parameters: G (jet speed) q (viewing angle) from continuum and VLBI monitoring: D + bapp G +  (Lähteenmäki and Valtaoja 1999) from SEDs

  18. Arshakian et al 2005

  19. Big BH mass  fast jet

  20. (quasars) Big BH mass  high absolute luminosity

  21. Peak frequency depends also on other parameters than just black hole mass

  22. Fast jets have low peak frequencies

  23. (quasars) Jet speed does not depend on jet luminosity

  24. jet speed jet luminosity BH MASS correlates with: Need more parameters! cross-correlations (or not): peak frequency

  25. LUMINOSITY and PEAK FREQUENCY depend on accretion rate (Wang et al. 2002) Wu et al. 2007 PEAK FREQUENCY depends on viewing angle (Saloranta, Nieppola, unpubl.)

  26. jet speed BH mass accretion rate jet luminosity viewing angle

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