1

High Energy Radiation from Black Holes

Gamma Rays, Cosmic Rays, and Neutrinos

Chuck DermerNaval Research Laboratorycharles.dermer@nrl.navy.mil

Govind MenonTroy Universitygmenon@troy.edu

2

Scientific Hypothesis

1. Highest energy and most powerful radiations made from black-hole engines

Synchrotron/Compton theory, compactness arguments, theory of relativistic flows

2. Ultra-high energy cosmic rays made in radio and gamma-ray loud blazars and GRBs

Hadronic vs. leptonic -ray and neutrino emission signatures in these sources

3. Turbulence or shocks accelerate particles to high energies

First and second-order Fermi acceleration; binary collision processes; blast wave physics

4. Energy source is the black-hole rotation and accretion

Extraction of energy through the Blandford/Znajek process

3

Press Restatement

BLACK HOLES ARE RESPONSIBLE FOR THE MOST

ENERGETIC COSMIC PARTICLES AND RADIATION

 

Blasts of radiation brighter than a trillion suns. Charged particles with the energy of a well-thrown baseball. Jets of magnetized plasma streaming across intergalactic space. What do these have in common? Their energy is derived from black holes.

Dermer and Menon: 2009 Fermi Symposium11/04/2008 4

Gamma Ray Galaxies: Black-Hole Powered

Two classes: 1. Active galaxies: Nearly 700 GeV,1 30 TeV; including 10 GeV and

TeV radio galaxies/SSRS/RLNLS1s2. Star-forming galaxies: Milky Way, LMC, NGC 253, M82,…M31(?)

LAT 1 year sky image2

1talk, B. Lott2Fermi talks

Gamma-ray luminosity of blazars: > trillion Solar luminosities

Dermer and Menon: 2009 Fermi Symposium11/04/2008 5

Gamma Ray Galaxies: Cosmic-ray/supernova powered

Two classes: 1. Active galaxies: Nearly 700 GeV,1 30 TeV; including 10 GeV/TeV radio

galaxies2. Star-forming galaxies: Milky Way, LMC, NGC 253, M82,…M31(?)

LAT 1 year sky image2

1talk, B. Lott2Fermi talks

Gamma-ray luminosity of Milky Way: ~100,000 Solar luminosities

galactic cosmic-rayInduced rays

Dermer and Menon: 2009 Fermi Symposium11/04/2008 6

The -ray/cosmic-ray connection

Nearby, low luminosity star-forming gamma-ray galaxies (millions x Solar luminosity) :

powered by supernovae explosions and collapse to neutron stars?

Distant, highly luminous active gamma-ray galaxies (trillions x Solar luminosity) :

powered by black holes?

Why so many detected black-hole powered gamma-ray galaxies (distant and therefore very luminous), and so few detected star-forming gamma-ray galaxies (nearby and therefore weak)?

Fermi mechanism predicts that highest energy particles made by sources with largest compactness = luminosity/size

Large compactness found in stellar core collapse to a neutron star forming supernovae and supernova remnants

Fermi map of SNR RX J1713.7−3946

Dermer and Menon: 2009 Fermi Symposium11/04/2008 7

Sources of the highest energy radiations

Very highest energy radiations, including ultra-high energy cosmic rays, made by black holes1. stellar core collapse to a black hole (gamma ray burst)2. rotating supermassive black holes3. microquasars in galaxies

Huge compactness found near accreting black holes, especially if rotating

Ultra-high energy cosmic rays from Centaurus A?

Moskalenko, et al. 2008

Cen A power: Bolometric radio power: 4×1042 erg s-1

Gamma-ray power: 5×1041 erg s-1

Hard X-ray/soft -ray power: 5×1042 erg s-1

UHECR power: few ×1040 erg s-1

11/04/2008 8

Black Hole Electrodynamics and Energy Extraction

Govind MenonTroy University

&Charles Dermer

U.S. Naval Research Laboratory

11/04/2008 9

E&B fields in Flat Space-time

0

0

0

0

123

132

231

321

BBE

BBE

BBE

EEE

F

The Maxwell Tensor in Special Relativity

2222 dzdydxdtg

DE

HB

11/04/2008 10

How do we define E&B fields? The Maxwell Tensor in General Relativity

0

0

0

0

123

132

231

321

gH

gHD

gH

gHD

gH

gHD

DDD

F

jiij dxdxdtddt 2 222

ijijgg detdet

11/04/2008 11

BEHD

,,

BDE

DBH

,0,0

where

even in “vacuum”

11/04/2008 12

(E,B) & (D,H) then satisfy

0 B D

0 EBt

JHDt

11/04/2008 13

24sin

cos2

aB r

52 sin

cos2

aE

242 sin

cos2

aB

22 2 aMrr

2222 cosar

22222 sin aar

Lambda is any function of theta.

11/04/2008 14

Energy and Angular Momentum Extraction

09

22

40

8d

Sin

Cos

adABH

dt

drr

r

07

22

30

8d

Sin

Cos

adABH

dt

dlrr

r

11/04/2008 15

The current vector

n

aJ

sin

cos1242

aarn ,0 , ,1 22

Note: n is the inward pointing principal null vector field in the Kerr Geometry.

11/04/2008 16

Solution

22

Mr

a

Hr aQB

2

sin1 0

rBE sinrBH

11/04/2008 17

6

222 mCE H

Krasnopolsky

Electromagnetic extraction of energy from hole

]2

)[arctan(20

M

a

r

a

ar

B

dt

dE

(figure courtesy R. Blandford)

11/04/2008 18

Angular Dependence of Energy Extraction

Energy Flux

i.e., most of the energy extraction takes place along the equatorial plane

2

02

2

2

sin

B

r

a

dAdt

Ed H

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

a = 0.1 a = 0.5 a = 0.9 a = 0.99

Pole, 0o

Equator

90o

45o

11/04/2008 19

BZ extraction of Power

]2

[arctan 2

0

M

a

r

a

ar

QP

-19

47 s ergs 102 MlP EDD

ii MMM 10

11/04/2008 20

The results presented here are used to argue that rotating black holes are the sources of the highest energy radiations

For details, see

High Energy Radiation from Black Holes(Princeton Univ. Press 2009)

Charles Dermer and Govind Menonand our poster

11/04/2008 21

Resurrection of the solution

Thus far we only looked at energy extraction resulting from Electromagnetic Poynting Flux.

The particle jet vanishes along the equatorial plane. It may well peak close to the polar axis of the Kerr Geometry

11/04/2008 22

Resurrection of the solution It is possible construct an exact

solution where the current flows through the out flowing null geodesic of the Kerr geometry.

The out flowing null geodesic can be decomposed to two timelike curves (corresponding to matter sources).