The most powerful persistent engine of Nature Gabriele Ghisellini INAF-Osservatorio di Brera...

The most powerful The most powerful persistent engine of persistent engine of

NatureNatureGabriele Ghisellini

INAF-Osservatorio di INAF-Osservatorio di BreraBrera

Fabrizio Tavecchio, Laura Maraschi, Annalisa Celotti, Tullia Sbarrato

With:

== EE mcmc

22

EfficiencyEfficiency

Sugar saccharose C12H22O111g 1g 4 kcal= 16.2 kJ = 1e23 eV = 4.7 eV per molecule 4 kcal= 16.2 kJ = 1e23 eV = 4.7 eV per molecule

EE

mcmc22== == 1.6x101.6x101111erg erg

9x109x1020 20 ergerg1.8x101.8x10-10-10==

mgmghh mcmc22

== == 980x10980x104 4 (h/100 (h/100 m)m) 9x109x1020 20 ergerg

1010-14-14~~

mvmv22 2 2

mcmc22

== == (v/100 (v/100 km/h)km/h)22

4x104x10-15-15(v/(v/c)c)22 22

==

Nuclear fissionNuclear fission

EE

mcmc22== == 0.2x100.2x1099eV eV

235x9.4x10235x9.4x108 8

eVeV

9x109x10-4-4~~

== 0.008 x 0.1 0.008 x 0.1

~ 8x10~ 8x10-4-4

FusioFusionn

== 0.1 up to 0.3 for accreting 0.1 up to 0.3 for accreting Kerr Kerr (Thorne 1974) (Thorne 1974)

== GM m GM m R mcR mc22 ==11

22RRg g 2R 2R

AnnihilationAnnihilation= = 11

Nuclear Nuclear Fusion/AccretiFusion/Accretionon

AccretionAccretion

????

AnnihilatioAnnihilationn

MMBHBH = 5x10 = 5x10-3-3MMbulgebulge (Kormendy & Ho 2013 (Kormendy & Ho 2013 ARAA)ARAA)

AccretionAccretion

????

BH = 0.1; = 0.008x0.1=8x10-4

EEBHBH = 5/8 E = 5/13 E = 5/8 E = 5/13 Etottot

AccretionAccretion

????

Jets?Jets?

Power of Power of jets in jets in blazarsblazarsX-ray cavities

Power of Power of jets in jets in blazarsblazarsX-ray cavities

Minimum energyMinimum energy

ttlobelobe

Power of Power of jets in jets in blazarsblazarsX-ray cavities

PV work / tPV work / tsoundsound

Power of Power of jets in jets in blazarsblazarsX-ray cavities

Measure the size, apply Measure the size, apply SSC model, find SSC model, find and # of and # of e-e-

1992: launch of EGRET on the 1992: launch of EGRET on the Compton Gamma-ray Compton Gamma-ray Observatory Observatory

Power of Power of jets in jets in blazarsblazarsX-ray cavities

PPr r = radiation ~ = radiation ~ LLobsobs//22PPe e = relat. = relat. electronselectronsPPp p = protons= protonsPPB B = B-field= B-field RR

jet power and accretion jet power and accretion luminosityluminosity

~1017 cm

Shakura-Sunyaev disk: Ld

Pjet = Pe+Pp+PB

If you want to compare disk If you want to compare disk luminosity and jet power,luminosity and jet power,the best sample is:the best sample is:

Blazars detected Blazars detected by Fermi by Fermi L Lobs, jet obs, jet with broad emission lines with broad emission lines LLdiskdisk

Shaw+ 2012: FSRQs (~220 sources)Shaw+ 2013: BL Lacs (26 with BLR)

The jet cannot have less power than what The jet cannot have less power than what required to produce the observed required to produce the observed luminosity:luminosity:

PPjetjetLLobsobs22

>>

If PIf Pjetjet is twice as much, is twice as much, halves. halves.We can take PWe can take Pradrad as the minimum P as the minimum Pjet.jet.This limit is model-independent.This limit is model-independent.

The jet cannot have less power than what The jet cannot have less power than what required to produce the observed required to produce the observed luminosity:luminosity:

PPjetjetLLobsobs22

>>

If PIf Pjetjet is twice as much, is twice as much, halves. halves.We can take PWe can take Pradrad as the minimum P as the minimum Pjet.jet.This limit is model-independent.This limit is model-independent.

GG+

Natu

re, 2

014

GG+

Natu

re, 2

014

From PFrom Pradrad to P to Pjetjet

minmin total number of e- (and of protons, if no total number of e- (and of protons, if no pairs…)pairs…)

Presence of electron positron pairsPresence of electron positron pairs

Radiative model: SSC vs EC vs baryonsRadiative model: SSC vs EC vs baryons

From PFrom Pradrad to P to Pjetjet

minmin total number of e- (and of protons, if no total number of e- (and of protons, if no pairs…)pairs…)

Presence of electron positron pairsPresence of electron positron pairs

Radiative model: SSC vs EC vs baryonsRadiative model: SSC vs EC vs baryonsdoesn’t fitdoesn’t fit even more powereven more power

disk

synchrsynchroo

SSC

SSC

EECC

Low energy e- Low energy e- ! !

disk

synchrsynchroo

SSC

SSC

EECC

““X-ray valley”X-ray valley”

disk

synchrsynchroo

SSC

SSC

EECC

““X-ray valley”X-ray valley”

Nem

men

+ S

cien

ce

Nem

men

+ S

cien

ce

2012

2012

blazarsblazars

GRBsGRBs

log Prad

PPjetjet=10 =10 PPradrad

PP jetjet = = PP radrad

GG+

Natu

re 2

014

GG+

Natu

re 2

014If one p per e-If one p per e-

1 proton per electron 1 proton per electron no no pairspairs

GG+

Natu

re, 2

014

GG+

Natu

re, 2

014

If one p per e-If one p per e-

Relat. Relat. electronselectrons

Magnetic FieldMagnetic Field

RadiationRadiation

DiskDisk

Apparent paradox:Apparent paradox:

Jet power proportional to accretionJet power proportional to accretion

And yet it is greater….And yet it is greater….

PPBZBZ ~ a ~ a22BB22MM22

Blandford ZnajekBlandford Znajek

PPBZBZ ~ a ~ a22BB22MM22

PPBZBZ ~ a ~ a22BB22RRgg22c c Poynting Poynting

FluxFlux

Blandford ZnajekBlandford Znajek

PPBZBZ ~ a ~ a22BB22MM22

PPBZBZ ~ a ~ a22BB22RRgg22c c Poynting Poynting

FluxFluxPPBZBZ ~ a ~ a22cc22 RRgg

22c c cc22~~BB22/8/8

PPBZBZ ~ a ~ a22MMcc22

Blandford ZnajekBlandford Znajek

Rotation > AccretionRotation > AccretionB-field amplified by accretion can tap the spin energy of the B-field amplified by accretion can tap the spin energy of the holehole

This process is very efficientThis process is very efficient

The B-field “does not work”, the jet power comes from the BH The B-field “does not work”, the jet power comes from the BH spinspin

Yet it is the catalyst for the process. No B no jet.Yet it is the catalyst for the process. No B no jet.

But B is linked to accretion, that’s why PBut B is linked to accretion, that’s why Pjetjet is propto L is propto Ldd

Shows results from the fiducial GRMHD simulation A0.99fc for a BH with spin parameter a = 0.99; see Supporting Information for the movie.

Tchekhovskoy A et al. MNRAS 2011;418:L79-L83

© 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS

Pjet Mc2

Shows results from the fiducial GRMHD simulation A0.99fc for a BH with spin parameter a = 0.99; see Supporting Information for the movie.

Tchekhovskoy A et al. MNRAS 2011;418:L79-L83

© 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS

Pjet

Mc2

On average: 1 g in On average: 1 g in 1.5 c 1.5 c22 erg out erg out

ConclusionConclusionPPjetjet ~ Mc ~ Mc22,, larger than Llarger than Ldd The jet uses to energy stored in the The jet uses to energy stored in the

rotation of the hole, that was rotation of the hole, that was provided by accretion. But it takes provided by accretion. But it takes it out faster thanit out faster than when it was put when it was put in.in.