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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, Helsinki University of Technology or, ”The usefulness of flux density monitoring”
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BH mass BH spin viewing angle accretion rate environment? age? redshift? gas content? magnetic fields?... ?
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WHAT IS REALLY FUNDAMENTAL?
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100 brightest radio AGN: highly selected, highly boosted sample viewing angle (Hovatta et al. in preparation) NEED LARGER SAMPLES!
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© Alan Marscher
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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
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SIMULATIONS?
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Aloy et al. 2003Gómez et al. 2001 Qualitative agreement -but need also quantitative: global and local parameters vs. simulated parameters -and also -parameter space
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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!)
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VLBA with all frequencies and polarization... (Savolainen et al., 2006, 2007) LOCAL data!
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...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?
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THEORY?...far from the humble life of an observer...
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3C 279, June 1991: six theories, six acceptable(?) fits to data...
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Marscher & Gear shock-in-jet model (1985) (picture courtesy of Marc Türler)
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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)
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© Alan Marscher KNOW where radio variations come from: spatial and temporal anchor
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Origin of gamma-rays? external photon dominated (EC) ”where the photons are” synchrotron photon dominated (SSC) ”where the electrons are” INVERSE COMPTON RADIATION
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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%
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1)radio flare / new shock emerges 2) gamma-ray flare (EC photons) - - - parsec(s) - - -
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1)radio flare / new shock emerges from radio core 2) shock grows, gamma peaks (SSC photons) - - - parsec(s) - - -
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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
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Blazar sequence? (Ghisellini et al. 1998) One-parameter (total power) family: Most powerful sources have lowest synchrotron peak frequencies CLASSIFICATION?
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...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)
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dee ja nyypeak
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There is no blazar sequence.
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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
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(Hovatta et al., in preparation) Jet speeds and viewing angles from variability and VLBI
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Big BH mass fast jet ?
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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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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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