Colliding winds in pulsar binaries S.V.Bogovalov 1, A.V.Koldoba 2,G.V.Ustugova 2, D. Khangulyan 3, F.Aharonian 3 1-National Nuclear Research University (Moscow) 2-Institute of applied mathematics RAN (Moscow) 3-Max-Planck-Institute for Nuclear Physics (Heidelberg)

Candidates  PSR /2883  LS 5039  LSI  Cygnus X-1

System PSR /SS2883  Companion star Pulsar M ~ 10 Solar mass P=47.7 ms L ~ erg/s Lsd= erg/s T ~ K Stellar outflow Binary system  Polar wind Distance d =1.5 kpc Vp ~ 2000 km/s e=0.87 Mp ~ Solar mass/yr Periastron separation Equatorial outflow Dmin= cm Vd ~ km/s Md ~ Solar mass/yr

View on the system

Parameterization Separation distance D=1. At Lorentz factor γ >> 1 All the flow depends on the only parameter For PSR <η<1

The scheme of interaction of the winds

Basic problems at the numerical modeling  The position of the shocks and discontinues is unknown a priory  Large difference in equations and properties of the relativistic and nonrelativistic flows  Different Courant numbers in relativistic and nonrelativistic flows.  Instability of the contact discontinuity.

Two zone solution  Nearest zone includes all the regions of subsonic flows- Method of relaxation  Far zone – supersonic flow. Cauchy problem.

Method of solution in the nearest zone  The equations are solved only in the post shock regions  Adaptive mesh is used. Beams are fixed, position of fronts vary

Equations for the relativistic wind

Equations for the nonrelativistic winds

Dynamics of the discontinuities To define evolution of the shocks and of the shocks and Contact discontinuity The Reimann problem About discontinuity decay Has been solved

The method of solution In the far zone

Results 1. The termination shock front of the pulsar wind is not always closed. For η > the shock front is opened.

The shock front for plane parallel stellar wind

High η

Dependence of the fronts on η

Dependance of the asymptotic opening angle of the fronts on η

Energy flow in the relativistic post shock wind Total energy along flow line is conserved

Adiabatic cooling

Formation of relativistic jet-like flows in the post shock wind

The role of the magnetic field

For comparison - interaction of the magnetized isotropic pulsar wind with isotropic interstellar medium

Basic conclusions  relativistic wind in the post shock region becomes relativistic even at the distance comparable with the separation distance.  At higher distances the Lorentz factor can achieve initial values  Even moderate relativistic motion of the post shock plasma can have strong impact on the light curve of radiation (synchrotron and IC)  Adiabatic cooling can result into suppression of the synchrotron radiation and excess of IC radiation.