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The spectral sequence of blazars : present status and expectations from GLAST

The spectral sequence of blazars : present status and expectations from GLAST. L. Maraschi , G. Ghisellini and F.Tavecchio INAF - Osservatorio Astronomico di Brera. The Blazar Spectral Sequence. Fossati et al. 1998; Donato et al. 2001. RED. FSRQ. Average s pectral energy distributions

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The spectral sequence of blazars : present status and expectations from GLAST

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  1. The spectral sequence of blazars : present statusand expectations from GLAST L. Maraschi, G. Ghisellini and F.Tavecchio INAF - Osservatorio Astronomico di Brera

  2. The Blazar Spectral Sequence Fossati et al. 1998; Donato et al. 2001 RED FSRQ Average spectral energy distributions of blazars: a systematic dependence on jet luminosity ? th Th BL Lacs BLUE Laura Maraschi INAF-OABr

  3. Construction Method • Three different complete samples: 2Jy FSRQs, 1Jy BLLacs, EINSTEIN Slew Survey BL Lacs • Sources binned in radio luminosity irrespective of original sample • Averages of monochromatic luminosities within each bin Laura Maraschi INAF-OABr

  4. Theoretical modeling of individual sources shows that the sequence corresponds to a systematic change of the the model parameters Ghisellini et al. 1998………. Laura Maraschi INAF-OABr

  5. Jet - accretion flow connection From observations we can estimate the luminosity (or u.l.) of the accretion disk. Modelling SEDs with good data coverage (gamma important) the jet power can be estimated. Comparing the two involves the radiative efficiency of the accretion flow ~ 10%, for a standard disk Laura Maraschi INAF-OABr

  6. Jet power vs. accretion power From SEDs of objects with sufficient data At high P (FSRQ) Pjet = Paccdisk At low P (BL Lac) Pjet > LdisK If Pjet ~ Pdisk e < 0.01 Maraschi 2001 Maraschi & Tavecchio, 2003 Sambruna et al.2006, Laura Maraschi INAF-OABr

  7. The blazar sequence can be understood as a sequence in • m (Accretion rate in Eddington units ) - High accretion rates produce bright disks and powerful jets - Low accretion rates explain the absence of optical signatures of disks by radiatively inefficient accretion (ADAF) in less powerful jets - The sequence can be related to cosmological evolution of black hole masses (increasing with time) and accretion rates (decreasing with time) leading to an overall decrease of m Maraschi 2001; Boettcher & Dermer 2002; Cavaliere & D’ Elia 2002; Maraschi & Tavecchio 2003; • • Laura Maraschi INAF-OABr

  8. For these possible profound implications it is important to test and extend with GLAST the original blazar spectral sequence -- complete the gamma-ray coverage of the old samples … remove flaring bias at least for bright objects -- search for gamma–ray emission for other samples ( a gamma-ray selected sample? ) Laura Maraschi INAF-OABr

  9. MKN 421 A collection of X-ray and gamma-ray states: An obedient source Laura Maraschi INAF-OABr

  10. PKS 2155 An HBL of extreme luminosity; Jul 06 flare Foschini et al. (see Poster) Laura Maraschi INAF-OABr

  11. A high redshift extremely luminous FSRQ discovered with BAT (SWIFT) GLAST detection expected Sambruna et al. 2006 Laura Maraschi INAF-OABr

  12. J0746+25 A perfect fit to the sequence Laura Maraschi INAF-OABr

  13. 3C 454.3 A less extreme Gamma-ray Blazar from EGRET An extended X-ray jet discovered with CHANDRA Tavecchio et al 2007 Laura Maraschi INAF-OABr

  14. Changing the angle of view Observable with GLAST also at larger angles Note the change in the gamma-ray to blue bump ratio Laura Maraschi INAF-OABr

  15. Effect of the viewing angle within the sequence The position of the peaks does not change dramatically. The blue bump retains its high luminosity Laura Maraschi INAF-OABr

  16. Jet :Synchrotronand InverseComptoncomponents Disentangling disk and jet in “mixed” Blazar cores Accretion disk: Blue Bump and X-ray p.l. Sambruna et al. 2006 Laura Maraschi INAF-OABr

  17. 1136-135 FSRQ with extended X-ray jet EGRET u.l. Expect GLAST detection as for 0723+679 Sambruna et al 2006 Laura Maraschi INAF-OABr

  18. The effect of a change in gamma peak is illustrated: The gamma-ray luminosity decreases a lot but the kinetic power carried by the jet is the same Laura Maraschi INAF-OABr

  19. 1629+4008 An unusual object: An HBL with a Seyfert like accretion disk The jet SED Conforms to the sequence Padovani et al. 2002 Laura Maraschi INAF-OABr

  20. The optical spectrum suggests a Seyfert-like accretion disk with L = 4 x 10 (44) erg/s • The accreion rate must be above • 0.01 Eddington • This object should have relativly low mass10 (7-8) solar masses Need gamma-ray data to estimate the jet power Laura Maraschi INAF-OABr

  21. Synch.+IC model for 1629 +4008 Gamma-ray component uncertain: here EC, but SSC could fill the hole… GLAST observation needed ! Laura Maraschi INAF-OABr

  22. Conclusions • The unprecedented sensitivity of GLAST will allow to probe • Jets at intermediate angles and “intrinsically” less powerful jets in intermediate mass objects • Progress in understanding the jet spectral properties and the jet-disk connection is expected but requires multifrequency coverage Laura Maraschi INAF-OABr

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