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From the Black Hole to the Telescope: Fundamental Physics of AGN Esko Valtaoja Tuorla Observatory, University of Turku, Finland Metsähovi Radio Observatory,

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Presentation on theme: "From the Black Hole to the Telescope: Fundamental Physics of AGN Esko Valtaoja Tuorla Observatory, University of Turku, Finland Metsähovi Radio Observatory,"— Presentation transcript:

1 From the Black Hole to the Telescope: Fundamental Physics of AGN Esko Valtaoja Tuorla Observatory, University of Turku, Finland Metsähovi Radio Observatory, Helsinki University of Technology or, ”The usefulness of flux density monitoring”

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3 BH mass BH spin viewing angle accretion rate environment? age? redshift? gas content? magnetic fields?... ?

4 WHAT IS REALLY FUNDAMENTAL?

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6 100 brightest radio AGN: highly selected, highly boosted sample viewing angle (Hovatta et al. in preparation) NEED LARGER SAMPLES!

7 © Alan Marscher

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10 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? © Alan Marscher

11 SIMULATIONS?

12 Aloy et al. 2003Gómez et al. 2001 Qualitative agreement -but need also quantitative: global and local parameters vs. simulated parameters -and also -parameter space

13 Exponential, sharp flares (Valtaoja et al. 1999) Theory and simulations: quite different flare shapes (Gomez et al. 1997)... are we missing something crucial? (And: flat optically thin spectra,  = -0.25!)

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

15 ...gives us local information along and transverse to the jet (which you cannot get from single and/or low frequency VLBI) electron energy density vs. distance: constant? + jet/mf structures, instabilities, nonrelativistic plasma, speeds... FIRST STEPS TOWARD UNDERSTANDING THE INTERNAL STRUCTURE OF JETS...BUT WE LACK SIMULATIONS AND THEORY FOR COMPARISON! magnetic field vs. distance: 1/r?

16 THEORY?...far from the humble life of an observer...

17 3C 279, June 1991: six theories, six acceptable(?) fits to data...

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

19 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)

20 © Alan Marscher KNOW where radio variations come from: spatial and temporal anchor

21 Origin of gamma-rays? external photon dominated (EC) ”where the photons are” synchrotron photon dominated (SSC) ”where the electrons are” INVERSE COMPTON RADIATION

22 EGRET vs continuum sample: radio flare starts before gamma flare [Valtaoja & Teräsranta 1995; Lähteenmäki & Valtaoja 2003] P = 99,9 % 3C 279: the more distant the shock, the weaker the gamma flare [Lindfors et al. 2006] P = 99,98%

23 1)radio flare / new shock emerges 2) gamma-ray flare (EC photons) - - - parsec(s) - - -

24 1)radio flare / new shock emerges from radio core 2) shock grows, gamma peaks (SSC photons) - - - parsec(s) - - -

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

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

27 ...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)

28 dee ja nyypeak

29 There is no blazar sequence.

30 BH MASS as the fundamental parameter? (work in progress, Tuorla & Metsähovi): BH MASS 2 main observables: L (peak) DOPPLER- (peak) CORRECTED! 2 main jet parameters:  jet speed)  viewing angle) from SEDs from continuum and VLBI monitoring: D +  app   +  (Lähteenmäki and Valtaoja 1999) from spectroscopy and imaging

31 (Hovatta et al., in preparation) Jet speeds and viewing angles from variability and VLBI

32 Big BH mass  fast jet ?

33 BH MASS as the fundamental parameter? (work in progress, Tuorla & Metsähovi & UNAM): BH MASS 2 main observables: L (peak) DOPPLER- (peak) CORRECTED! 2 main jet parameters:  jet speed)  viewing angle) from SEDs from continuum and VLBI monitoring: D +  app   +  (Lähteenmäki and Valtaoja 1999) from spectroscopy and imaging 2 more observables: L (peak, IC) (peak, IC)

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35 Radio monitoring provides movies (with not too many frames missing) instead of snapshots: temporal anchor Only in radio we are pretty sure where the flux and the variability comes from: spatial anchor Especially when combined with other multifrequency and multiapproach data, radio monitoring is a very powerful tool for testing various theoretical models, AGN classification and unification, and a key for deriving the fundamental properties of jets.

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