| Abstract |
Jets powered by high-mass X-ray binaries must traverse the powerful wind
of the companion star. We present the first global 3-D simulations of
jet-wind interaction in high-mass X-ray binaries. We show that the jet
can be re-collimated where the internal jet pressure is equal to the
wind ram pressure, and beyond the re-collimation, the jet thickness, h,
follows from pressure equilibrium between the jet and bow-shock. Based
on this analytic jet model, we analyze the effects of jet-wind
interaction, bending the jet to an asymptotic angle
ψ∞. Through both numerical study and analytic
approach, we formularize the ψ∞ as a function of
jet power and wind thrust, which can be used to constrain the jet power
with known wind parameters. For example, we apply the formula to the
case of Cygnus X-1, and show that given wind parameters for the O9.7 Iab
companion, the jet power should be larger than 1.47 ×
1036 ergs s-1 to keep the jet straight against the
wind momentum flux as it is observed by VLBA. We further discuss the
case where the initial jet is inclined relative to the binary orbital
axis, which shows asymmetric behavior between approaching jet and
receding jet from the companion star. We also analyze the case of Cygnus
X-3 and show that jet bending is likely negligible unless the jet is
significantly less powerful or much wider than currently thought. |