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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 - PowerPoint PPT Presentation
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Hydrodynamics of Small-Scale Jets: Observational
aspectsEsko Valtaoja
Tuorla Observatory, University of Turku, FinlandMetsähovi Radio Observatory, Helsinki University of Technology
TUORLA-METSÄHOVI AGN GROUP: Talvikki Hovatta, ElinaLindfors, Anne Lähteenmäki, Elina Nieppola, Pia-Maria Saloranta,Tuomas Savolainen, Ilona Torniainen, Merja Tornikoski, Kaj Wiik
Meg Urry 2007: ”Luckily, nobody remembers what wesaid 25 years ago, and the old acetates have decayed.”
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?
Aloy et al. 2003 Gómez et al. 2001
Qualitativeagreement-but need alsoquantitative:global andlocal parametersvs. simulatedparameters
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)
magnetic fieldvs. distance
electron energy densityvs. distance
+ jet/mf structures,instabilities, nonrelativisticplasma, speeds, IC fluxes...
SAVE VLBA BY USING ITS FULL POWER!
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)
LOCALdata!
Lindfors et al. 2005, 2006: shock and jet component spectra(+ SSC spectra) from mf continuum monitoring and 3-D fitsimultaneously to all data
VLBI: Savolainen et al. 2007
Exponential, sharp flares (Valtaoja et al. 1999)
Theory and simulations: quite different flare shapes(Gomez et al. 1997) ... are we missing something crucial?
- 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 foreach: physics of the radio core!
Savolainen et al 2002
Jorstad et al.2001
Lähteenmäki & Valtaoja 2003
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)
(Heh.)
EC photonsare here!
radiocore
Blazar sequence?(Ghisellini et al. 1998)
One-parameter(total power) family:
Most powerful sourceshave lowest synchrotronpeak frequencies
...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)
Doppler boosting vs. peak frequency(PMS + Nieppola, QSOs and BLOs)
Nu peak (z, D -corrected)
11 12 13 14 15 16
D(v
ar)
0
5
10
15
20
25
30
Wu et al 2007:
D(var) = [TB(var)/TB(lim)]1/3 (Lähteenmäki & Valtaoja 1999)
Correcting the luminositiesfor Doppler boosting totallydestroys the last traces ofthe ”blazar sequence”(Saloranta, Nieppola,in preparation) (quasars)
(BL Lacs)
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
Arshakian et al 2005
Big BH mass fast jet
Big BH mass high absolute luminosity
(quasars)
Peak frequency depends also on other parameters than just black hole mass
Fast jets have low peak frequencies
Jet speed does not depend on jet luminosity
(quasars)
BH
MA
SS
corr
elat
es w
ith
:
jet speed
jet luminosity
peak frequency
Nee
d m
ore
para
met
ers!
cros
s-co
rrel
atio
ns
(or
not
):
LUMINOSITY and PEAK FREQUENCYdepend on accretion rate (Wang et al. 2002)
PEAK FREQUENCYdepends on viewing angle(Saloranta, Nieppola, unpubl.)
Wu et al. 2007
BH mass
jet speed
jet luminosity viewing angle
accretionrate