TY - JOUR
T1 - Opening angles, Lorentz factors and confinement of X-ray binary jets
AU - Miller-Jones, J. C.A.
AU - Fender, R. P.
AU - Nakar, E.
PY - 2006/4
Y1 - 2006/4
N2 - We present a collation of the available data on the opening angles of jets in X-ray binaries, which in most cases are small (≲ 10°). Under the assumption of no confinement, we calculate the Lorentz factors required to produce such small opening angles via the transverse relativistic Doppler effect. The derived Lorentz factors, which are in most cases lower limits, are found to be large, with a mean > 10, comparable to those estimated for active galactic nuclei (AGN) and much higher than the commonly assumed values for X-ray binaries of 2-5. Jet power constraints do not, in most cases, rule out such high Lorentz factors. The upper limits on the opening angles show no evidence for smaller Lorentz factors in the steady jets of Cygnus X-l and GRS 1915+105. In those sources in which deceleration has been observed (notably XTEJ1550-564 and Cygnus X-3), some confinement of the jets must be occurring, and we briefly discuss possible confinement mechanisms. It is however possible that all the jets could be confined, in which case the requirement for high bulk Lorentz factors can be relaxed.
AB - We present a collation of the available data on the opening angles of jets in X-ray binaries, which in most cases are small (≲ 10°). Under the assumption of no confinement, we calculate the Lorentz factors required to produce such small opening angles via the transverse relativistic Doppler effect. The derived Lorentz factors, which are in most cases lower limits, are found to be large, with a mean > 10, comparable to those estimated for active galactic nuclei (AGN) and much higher than the commonly assumed values for X-ray binaries of 2-5. Jet power constraints do not, in most cases, rule out such high Lorentz factors. The upper limits on the opening angles show no evidence for smaller Lorentz factors in the steady jets of Cygnus X-l and GRS 1915+105. In those sources in which deceleration has been observed (notably XTEJ1550-564 and Cygnus X-3), some confinement of the jets must be occurring, and we briefly discuss possible confinement mechanisms. It is however possible that all the jets could be confined, in which case the requirement for high bulk Lorentz factors can be relaxed.
KW - ISM: jets and outflows
KW - Relativity
KW - Stars: winds, outflows
KW - X-rays: binaries
UR - http://www.scopus.com/inward/record.url?scp=33645662230&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2966.2006.10092.x
DO - 10.1111/j.1365-2966.2006.10092.x
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AN - SCOPUS:33645662230
SN - 0035-8711
VL - 367
SP - 1432
EP - 1440
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -