Polarimetric signatures of infrared jets in X-ray binaries

T. Shahbaz, R.P. Fender, Christopher Watson, K. O'Brien

Research output: Contribution to conferencePaper


We present near-infrared linear spectropolarimetry of a sample of persistent X-ray binaries, Sco X-1, Cyg X-2 and GRS 1915+105. For Sco X-1 and Cyg X-2, the polarization levels at 2.4 µm are 1.3+/-0.10% and 5.4+/-0.7%, respectively, which is greater than the polarization level at 1.65 µm. This cannot be explained by interstellar polarization or electron scattering in the anisotropic environment of the accretion flow. We propose that the most likely explanation is that this is the polarimetric signature of synchrotron emission arising from close to the base of the jet. For Sco X-1 the position angle of the radio jet on the sky is approximately perpendicular to the near-infrared position angle (electric vector), suggesting that the magnetic field is aligned with the jet. These observations may be a first step towards probing the ordering, alignment, and variability of the outflow magnetic field, in a region closer to the central accreting object than is observed in the radio band.
Original languageEnglish
Number of pages3
Publication statusPublished - Aug 2009
EventMagnetic Fields in the Universe II: from Laboratory and Stars to the Primordial Universe - Cozumel, Mexico
Duration: 01 Aug 200901 Aug 2009


ConferenceMagnetic Fields in the Universe II: from Laboratory and Stars to the Primordial Universe

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