A Two-Flow Model for Microquasars

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Nov 15, 2013 (3 years and 9 months ago)

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P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

A Two
-
Flow Model for Microquasars

P.O. Petrucci

J. Ferreira, G. Henri, G. Pelletier, L. Sauge


Laboratoire d'Astrophysique de Grenoble

France

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

Complex Spectral and Temporal
behaviours

From Belloni 2005, astro
-
ph/0504185

(see also Corbel et al.2004; Belloni et al., 2005; Fender et al. 2004)

Jet

No Jet

Jet

Radio flares

Jets are energetically, dynamically and spectrally important

GX 339
-
4

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

Evidence for different jet velocities

Dhawan et al. 2000


Compact jets observed during low
-
hard
states


Brightness contrast implies

~ 0.1 to 0.5

Mirabel & Rodriguez 1994



Superluminal

ejections

during

flares






ultra
-
relat
.

velocities


(cf. also Fomalont et al. 2001a,b in Sco X
-
1; Fender et al. 2004 in Cir X
-
1;

Migliari et al. 2005 in SS 433)

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

The Two
-
Flow Model

A highly relativistic electron
-
positron

beam inside the MHD jet

Two flow model : 2 distinct flows

(Sol, Pelletier, Asséo ‘85, Henri & Pelletier ‘91)

Already applied with success for AGNs
(Sauge & Henri 2004; Marcowith et al.1995, 1998

A

midly

relativistic

electron
-
proton

MHD

jet

produced

by

the

accretion

disc
:


M
agnetic

Ac
cretion
-
E
jection

S
tructure

(MAcES)

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005







The non
-
relativistic MHD jet component




JED : weakly dissipative steady

disc solution!




B

field

extracts

angular

momentum

and

power

from

the

JED

(Jet

Emitting

Disk)
.


Ferreira (1997)

Colors: density

Solid line: streamlines

Complete

self

consistent

accretion
-
ejection

solutions

under

self

similarity

assumption

(Ferreira

1997
;

Casse

&

Ferreira

2000
;

Ferreira

&

Casse

2004
)




Jet

only

mildly

relativistic

(

~
0
.
3
-
0
.
5
)


Baryonic jet emitted by the accretion disk through MHD
mechanism

(Blanford & Payne 1982)

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005







The ultra
-
relativistic pair beam



In

situ

generation

of

a

pair

plasma

in

the

MHD

funnel

trough


annihilation

X
-
ray

and

gamma
-
ray

emission

by

IC

and/or

SSC

Efficient

acceleration

mechanism

:

Compton

rocket

effect

(recoil

effect

by

Anisotropic

Inverse

Compton

scattering)

(O'Dell 1981; Renaud & Henri 1998)

Continuous

heating

by

MHD

turbulence

necessary

for

a

pair

runaway

to

occur
.

(Henri & Pelletier 1991)

The

MHD

jet

allows

the

collimation

of

the

relativistic

beam

(an

ultra
-
relat
.

beam

cannot

be

self
-
collimated)

(Bogovalov

2001
,

Pelletier

2004
)

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005


Spectral Components

Multi
-
black body spectrum

The outer standard accretion disc




For r > r
tr




m = cste

.

A key parameter: the transition radius
r
tr
between the MAcES and the

outer part of the disc

r
tr

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

Mimic a truncated accretion disc,

a low radiative plasma (ADAF),

BUT

completely consistent with a jet

Weakly dissipative!

The inner Jet Emitting Disc




For r < r
tr




m


r




Most of the accretion power goes

into Poynting flux

.

r
tr


Spectral Components

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

Thermal

comptonization

on

accretion

disc

soft

photons

(dominated

by

SAD

emission

at

r
tr
)

The jet basis = hot thermal corona




Heated by a fraction of the magnetic

Power



Dynamical corona. MHD jet models

suggest

~0.3)


r
tr


Spectral Components

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005


Synchrotron spectrum integrated

along the jet axis

Optically

thick

in

radio
.

May

extend

up

to

the

X
-
rays


(e
.
g
.

Blandford

&

Payne

1982
,

Markoff

et

al
.

2004
)



The

large

scale

MHD

jet





Powered

by

the

magnetic

power

released

by

the

disc



Non
-
relativistic

speed

(

~
0
.
3
-
0
.
5
)



ne(z),

B(z)

computed

self
-
consistently



r
tr


Spectral Components

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

Pair creation possible in the

high Intermediate hard state


The

pair

beam





The



optical

depth

can

be

written




(E

)~(L
1keV
)/(0.1L
edd
)(E

/1 MeV)


Synchrotron self Compton and
external Compton.

Flares. Superluminal motion

Radiates

in

X

down

to

the

radio

(opt
.

thin)

(Saugé & Henri 2004; Marcowith et al. 1995, 1998)



Heated

by

a

fraction

of

the

magnetic

power

r
tr


Spectral Components

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

Jet

dominated

state



Large

r
tr



Strong

jet

(opt

thick

radio)



Strong

thermal

corona



Weak

disc

Flaring

state

dominated

by

pairs



r
tr

decreases,

disc

brightens



Jet

and

corona

weaken
.

X
-
ray

steepen



Pair

beam

forms

(opt
.

thin

radio,


superluminal

motion)
.
Strong

flares

may


destroy

the

jet

Disc

dominated

state



r
tr

too

small

for

jet

formation

(no

or

weak

radio)



Strong

disc

emission



Possible

non
-
thermal

emission


(hard

tail)

from

magnetic

flares

MAcES

reconstruction



r
tr

increases



Disc

weakens



Jet

and

corona

brighten



low

intensity
:

no

pair

beam

soft

hard

low

high

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

Conclusions and perspectives



Self consistent Magnetic Accretion
-
Ejection structure (

< 0.5)




Precise computation of the ultra relativisitic pair beam

(Ferreira 1997; Casse & Ferreira 2000; Ferreira & Casse 2004)

(Markowith et al. 1998; Sauge & Henri 2004)

}

Two Flow

Model

A new unified model for the spectral emission of microquasars that lies
on strong physical basis:

where spectral variability simply due to variation of r
tr

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

What drives r
tr
?

MHD Models show that a MAcES exists for a
range

of
m

(


1).



For
m<m
min



jet destruction



For
m>m
max



jet formation

P
gaz
+P
rad

P
mag

m=

(

)
JED

=m
(m)

.

m + 2nd parameter.... B or more precisely

.

Work in progress


(effects of pairs on the MHD structure, QPOs, ...)

P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

1/

b

Observer

No jet
-
like structure is observed


Observer

No collimation

Collimation

1/

b

A jet
-
like structure is observed


q
jet

< 1/

b



q
jet

> 1/

b



P.O. Petrucci

High Energies in the Highlands, Fort William, Scotland, 27 June


1 July 2005

Bradshaw et al. (1997), Fomalont et al.
(2001a,b)

Flares

Invisible highly

relativistic beam


>2

Lobes energized by beams

and moving at 0.4c

Evidence for different jet velocities

Sco X
-
1