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

The spectral sequence The spectral sequence of blazars : present of blazars : present

statusstatusand expectations from and expectations from

GLASTGLASTL. MaraschiL. Maraschi, G. Ghisellini and , G. Ghisellini and

F.TavecchioF.Tavecchio

INAF - Osservatorio Astronomico di INAF - Osservatorio Astronomico di BreraBrera

First GLAST Symposium - Stanford U - Feb 20First GLAST Symposium - Stanford U - Feb 200707

Laura Maraschi INAF-OABrLaura Maraschi INAF-OABr

The Blazar Spectral Sequence

FSRQ

BL Lacs

Fossati et al. 1998; Donato et al. 2001

RED

BLUE

Th

th

Average spectral energy distributions of blazars:

a systematic dependence on jet luminosity ?



Construction Method Construction Method

• Three different complete samples:Three different complete samples: 2Jy FSRQs, 1Jy BLLacs, EINSTEIN Slew 2Jy FSRQs, 1Jy BLLacs, EINSTEIN Slew

Survey BL LacsSurvey BL Lacs• Sources binned in radio luminosity Sources binned in radio luminosity

irrespective of original sampleirrespective of original sample• Averages of monochromatic Averages of monochromatic luminosities within each binluminosities within each bin



Theoreticalmodeling of individual sources shows thatthe sequence corresponds to a systematicchange of the the model parameters

Ghisellini et al.1998……….



Jet - accretion flow Jet - accretion flow connectionconnection

From observations we can estimate the luminosityFrom observations we can estimate the luminosity

(or u.l.) of the accretion disk.(or u.l.) of the accretion disk.

Modelling SEDs with good data coverage (gammaModelling SEDs with good data coverage (gamma

important) the jet power can be estimated.important) the jet power can be estimated.

Comparing the two involves the radiative efficiencyComparing the two involves the radiative efficiency

of the accretion flow ~ 10%, for a standard diskof the accretion flow ~ 10%, for a standard disk



Jet power vs. accretion Jet power vs. accretion powerpower

Maraschi 2001Maraschi 2001Maraschi & Tavecchio, 2003Maraschi & Tavecchio, 2003Sambruna et al.2006,Sambruna et al.2006,

At high P At high P (FSRQ)(FSRQ)PPjet jet = Pacc= Paccdiskdisk

At low P (BL At low P (BL

Lac)Lac)

PPjet jet > L> LdisKdisK

If PIf Pjetjet ~ P ~ Pdiskdisk < 0.01< 0.01

From SEDs of objects with sufficient data



The blazar sequence can The blazar sequence can be understood as a be understood as a

sequence insequence in

- High accretion rates produce bright disks - High accretion rates produce bright disks and powerful jetsand powerful jets - Low accretion rates explain the absence of optical - Low accretion rates explain the absence of optical

signatures of disks by radiatively inefficient accretion signatures of disks by radiatively inefficient accretion (ADAF) in less powerful jets(ADAF) in less powerful jets

- The sequence can be related to cosmological evolution - The sequence can be related to cosmological evolution of black hole masses (increasing with time)of black hole masses (increasing with time) and accretion rates (decreasing with time) leading to and accretion rates (decreasing with time) leading to

an overall decrease of man overall decrease of m

Maraschi 2001; Boettcher & Dermer 2002; Cavaliere & D’ Elia 2002;Maraschi 2001; Boettcher & Dermer 2002; Cavaliere & D’ Elia 2002;Maraschi & Tavecchio 2003; Maraschi & Tavecchio 2003;

••m••

••

(Accretion rate in Eddington units )



For these possible profound implicationsFor these possible profound implications

it is important to test and extend withit is important to test and extend with

GLAST GLAST

the original blazar spectral sequencethe original blazar spectral sequence

-- complete the gamma-ray coverage of-- complete the gamma-ray coverage of

the old samples … remove flaring biasthe old samples … remove flaring bias

at least for bright objectsat least for bright objects

-- search for gamma–ray emission for-- search for gamma–ray emission for

other samples ( a gamma-ray selectedother samples ( a gamma-ray selected

sample? )sample? )



MKN 421

A collectionof X-ray andgamma-raystates:An obedientsource



PKS 2155

An HBL ofextreme luminosity;

Jul 06 flareFoschini et al.(see Poster)



A high redshift extremely luminous FSRQdiscoveredwith BAT(SWIFT)

GLAST detection expected

Sambruna et al.2006



J0746+25

A perfectfit to the sequence



3C 454.3A less extremeGamma-ray Blazar fromEGRET

An extended X-ray jet discoveredwith CHANDRA

Tavecchio et al 2007



Changing theangle of view

Observable with GLASTalso at largeranglesNote the changein the gamma-rayto blue bumpratio



Effect of theviewing anglewithin the sequence

The positionof the peaksdoes not changedramatically.The blue bumpretains its highluminosity



Accretion disk:

Blue Bump and X-ray p.l.Jet :Synchrotronand InverseComptoncomponents

Disentanglingdisk and jetin “mixed”Blazar cores

Sambruna et al.2006



1136-135FSRQ withextended X-ray jetEGRET u.l.

Expect GLASTdetection asfor 0723+679

Sambruna et al2006



The effectof a change in gamma peakis illustrated:

The gamma-rayluminositydecreases a lotbut the kineticpower carried by the jet is the same



1629+4008An unusualobject:

An HBL with aSeyfert likeaccretion disk

The jet SED Conforms to thesequence

Padovani et al.2002



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 estimatethe jet power



Synch.+ICSynch.+ICmodel for model for 1629 +40081629 +4008

Gamma-rayGamma-raycomponentcomponentuncertain:uncertain:here EC,here EC,but SSC couldbut SSC couldfill the hole…fill the hole…GLAST GLAST observationobservationneeded !needed !



ConclusionsConclusions

• The unprecedented sensitivity of GLAST The unprecedented sensitivity of GLAST will allow to probewill allow to probe

• Jets at intermediate angles and Jets at intermediate angles and “intrinsically” less powerful jets in “intrinsically” less powerful jets in intermediate mass objectsintermediate mass objects

• Progress in understanding the jet Progress in understanding the jet spectral properties and the jet-disk spectral properties and the jet-disk connectionconnection

is expected but requires multifrequencyis expected but requires multifrequency coverage coverage

Documents

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