from the black hole to the telescope: fundamental physics of agn esko valtaoja tuorla observatory,...
TRANSCRIPT
From the Black Holeto the Telescope:
Fundamental Physics of AGN
Esko ValtaojaTuorla Observatory, University of Turku, Finland
Metsähovi Radio Observatory, Helsinki University of Technology
or, ”The usefulness of flux density monitoring”
BH massBH spin
viewing angle
accretionrate
environment?age?redshift?gas content?magnetic fields?... ?
WHAT IS REALLY FUNDAMENTAL?
100 brightestradio AGN:
highly selected,highly boostedsample
viewingangle
(Hovatta et al.in preparation)
NEEDLARGERSAMPLES!
© Alan Marscher
NEED: basic GLOBAL and LOCALparameters from observations asinputs to theory / simulations...... which, in turn, should givepredictions which observers can test
GLOBAL: e.g., BH mass vs. jet speed?LOCAL: e.g., magnetic field strength along the jet?
© AlanMarscher
SIMULATIONS?
Aloy et al. 2003 Gómez et al. 2001
Qualitativeagreement-but need alsoquantitative:global andlocal parametersvs. simulatedparameters-and also-parameter space
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!)
VLBA with all frequencies and polarization...(Savolainen et al., 2006, 2007)
LOCALdata!
...gives us local information along and transverse to the jet(which you cannot get from single and/or low frequency VLBI)
electron energy densityvs. distance: constant?
+ jet/mf structures, instabilities,nonrelativistic plasma, speeds...
FIRST STEPS TOWARD UNDERSTANDING THE INTERNALSTRUCTURE OF JETS ...BUT WE LACK SIMULATIONS ANDTHEORY FOR COMPARISON!
magnetic fieldvs. distance: 1/r?
THEORY?
...far from the humble life of an observer...
3C 279, June 1991:six theories,six acceptable(?)fits to data...
Mar
sch
er &
Gea
r sh
ock
-in
-jet
mod
el (
1985
)
(picturecourtesy ofMarc Türler)
Ten years of 3C 279 cm-to-optical variations modelled as”M & G” shocks in a jet (Lindfors et al., 2006, originalcode developed by Marc Türler)
© A
lan
Mar
sch
er
KNOW whereradio variationscome from:spatial andtemporalanchor
Origin of gamma-rays?
external photondominated (EC)”where the photons are”
synchrotron photondominated (SSC)”where the electrons are”
INVERSECOMPTONRADIATION
EGRET vs continuum sample: radio flare starts before gamma flare[Valtaoja & Teräsranta 1995; Lähteenmäki& Valtaoja 2003] P = 99,9 %
3C 279: the moredistant the shock, theweaker the gamma flare [Lindfors et al. 2006]
P = 99,98%
1) radio flare / new shock emerges
2) gamma-ray flare (EC photons)
- - - parsec(s) - - - - - - parsec(s) - - -
1) radio flare / new shock emerges from radio core
2) shock grows, gamma peaks (SSC photons)
- - - parsec(s) - - - - - - parsec(s) - - -
radiogamma
Average delay from TFD/VLBI zero epoch to strong gammaflares ~ 2 months = parsecs, so External Compton fails...
...but the only alternative,synchrotron-self-Comptonalso fails (Lindfors et al.2005, 2006)
EC photonsare here!
radiocore
Blazar sequence?(Ghisellini et al. 1998)
One-parameter(total power) family:
Most powerful sourceshave lowest synchrotronpeak frequencies
CLASSIFICATION?
...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)
dee ja nyypeak
There is no blazar sequence.
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 VLBImonitoring: D + app + (Lähteenmäki and Valtaoja 1999)
from spectroscopyand imaging
(Hovatta et al., in preparation)
Jet speeds andviewing anglesfrom variabilityand VLBI
Big BH mass fast jet ?
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 VLBImonitoring: D + app + (Lähteenmäki and Valtaoja 1999)
from spectroscopyand imaging2 more
observables:L(peak, IC)
(peak, IC)
Radio monitoring provides movies (with not too manyframes missing) instead of snapshots: temporal anchor
Only in radio we are pretty sure where the fluxand the variability comes from: spatial anchor
Especially when combined with other multifrequency andmultiapproach data, radio monitoring is a very powerfultool for testing various theoretical models, AGN classificationand unification, and a key for deriving the fundamentalproperties of jets.
