the most powerful persistent engine of nature gabriele ghisellini inaf-osservatorio di brera...
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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.
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