Transcript High energy processes in massive binary systems.

Neutrinos produced by heavy
nuclei injected by the pulsars
in massive binaries
Marek Bartosik
&
W. Bednarek, A. Sierpowska
Erice ISCRA 2004
The purpose
 Neutrinos from massive binaries e.g.


Gaisser & Stanev 1985
Berezinsky et al. 1986
large angles – non eclipsing binaries
6 July 2004
ISCRA Erice 2004
2
Binary system
What we need?
no accretion
small separation
Binary with an energetic pulsar
6 July 2004
star with massive & fast wind
 WR or OB – perfect
ISCRA Erice 2004
3
The shock geometry
 The geometry of the shock is described by the
parameter
 = Lem/(c MlossVWR),
which is the ratio of momentum carried by the pulsar
wind and the momentum of the stellar wind.
Lem= 61031B122P-4 erg s-1,
 The distance from the pulsar to the termination shock
is:
 = 1/2D(1+1/2)
6 July 2004
ISCRA Erice 2004
Ball & Dodd 2001
4
Scenario
6 July 2004
ISCRA Erice 2004
5
Parameters

M  4 10 5 M sun yr 1
VW R  1400km s 1
Teff  1.4 105 K
Lem  6 1038 erg s 1
P  12.59ms
B psr  5 10 G
11
=0.06
RW R  1.6 Rsun
D  3.6 Rsun
e  0.0
6 July 2004
ISCRA Erice 2004
Cygnus X-3
d=10kpc
6
Iron from the NS surface
 Binding energy of the iron nuclei on the NS surface
is not known (2-3keV?).
 It is assumed that iron nuclei can be emitted for
(Usov&Melrose, 1995)
0.73
T  3.5 105 B12
K
 Temp. of NS star surface can be high enough:


In a short time after its formation
As a result of heating of the polar cap by e-m cascades
(polar cap model)
6 July 2004
ISCRA Erice 2004
7
Acceleration of nuclei
 Charged particles can be accelerated to the energy
E  Ze Lem / c
 Expected Lorentz factors of iron nuclei in Cyg X-3
7
~   3 10
Arons 0.3 (for Crab)
6 July 2004
ISCRA Erice 2004
then - 107
Arons, 1998
8
Optical depth
Optical depths for
dissociation of
single nucleon in
the PWZ for
different angles of
injection (from 0
to 150)
6 July 2004
ISCRA Erice 2004
9
Nucleons extraction
Number of
dissolved nucleons
from primary iron
nuclei during their
propagation in the
PWZ for angles
from 0 to 150
6 July 2004
ISCRA Erice 2004
10
Shock zone
 The magnetic field at the termination shock
at the „pulsar side” is 103 G
 Larmor radius for iron nuclei with Lorentz
factor 106 is 1010 cm
 Iron nuclei & protons can pass through the
shock.
6 July 2004
ISCRA Erice 2004
11
Magnetic field of WR star
  R 3
2
4
10
G

B

10
G (WR star)
for R  r  rA (dipole )
s
 
2
r
B

3

10
G (OB star)
3
s
V
 R
B (r )  Bs   2 for rA  r  R
(radial )
Vrot  (0.1  0.2)V
r
r
V
A
rot

V rot R
V
for
R
 r (toroidal )
V r r
Vrot
A

1  R / rA   ( R / rA ) 4

( Bs ) 2 R 2

2 M V
Eichler & Usov, 1993
rA- Alfven radius
6 July 2004
ISCRA Erice 2004
12
Nucleons above the PWZ
 Part of nucleons extracted from iron nuclei and
remnant nuclei impinge onto the massive star.
 Hadrons lose energy on pion production during
their propagation in the WR star atmosphere
A  p    
Atmosphere model:
Hamann 1985
___
        (  )
___
___
   e     (  )   e ( e )
6 July 2004
ISCRA Erice 2004
13
Can we get a neutrino?
If
 /  ,in   /  ,decay
pion decays and neutrino & muon are produced.
 /  ,decay  c   / 
   2.6  10 8 s
   2.2  10 s
6
6 July 2004
ISCRA Erice 2004
14
Lorentz factors
-106 thick
-107 thin
Spectra of neutrinos 0.2 R
comparison
0.4 R
star-
red
star -green
0.6 Rstar - blue
0.8 Rstar - violet
Modulation due to companion star matter
6 July 2004
ISCRA Erice 2004
15
Integral neutrino fluxes
Integral neutrino fluxes as a
function of the impact
parameter for the observer
in the plane of the binary
system at energies above:
102GeV - black
3102GeV - red
103GeV - green
3103GeV – blue
(=106 – thick, =107 – thin)
6 July 2004
ISCRA Erice 2004
16
=120-150
210-240
150-180
180-210
Spectra of neutrinos
240-270
270-300
Spectra of neutrinos for different viewing angles in respect to the plane of the binary; cos : 0.0-0.2
(black line), 0.2-0.4(red), 0.4-0.6(green) and 0.6-0.8(blue).  is azimuthal angle.
6 July 2004
ISCRA Erice 2004
17
Conclusions
 Heavy nuclei, if injected by a compact object inside the close massive
binary (e.g. similar to Cyg X-3), can significantly disintegrate in the
radiation field of a massive star.
Some neutrons dissolved from the nuclei impinge on the massive star
surface producing high energy neutrinos in the plane of the massive
binary.
Some protons and neutrons dissolved from nuclei and remnant nuclei,
after propagation in the magnetic field of the massive star above the
pulsar termination shock, can also impinge on the massive star surface
producing neutrinos at large angles to the plane of the binary system.
The flux of neutrinos produced at large angles to the system plane is
about 30% of the flux produced in the cone intercepted by the massive
star in the considered case.
6 July 2004
ISCRA Erice 2004
18
6 July 2004
ISCRA Erice 2004
19