2008/03/26 by D. M. Russell, R. P. Fender · 1 citation
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Collimated light #Cosmic dust #Galaxy #Gamma-ray bursts and supernovae #Infrared #Interstellar medium #Laser #Linear polarization #Optics #Physics #Polarimetry #Polarization (electrochemistry) #Position angle #Scattering #Telescope #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2008.13254.x
Accepted to be published in MNRAS; 13 pages, 6 figures
arxiv created 2008/03/26 · openalex publication_date 2008/05/07 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Near-infrared (NIR) and optical polarimetric observations of a selection of X-ray binaries are presented. The targets were observed using the Very Large Telescope and the United Kingdom Infrared Telescope. We detect a significant level (3σ) of linear polarization in four sources. The polarization is found to be intrinsic (at the >3σ level) in two sources; GRO J1655−40 (∼4–7 per cent in the H and Ks bands during an outburst) and Sco X–1 (∼0.1–0.9 per cent in the H and K bands), which is stronger at lower frequencies. This is likely to be the signature of optically thin synchrotron emission from the collimated jets in these systems, whose presence indicates that a partially ordered magnetic field is present at the inner regions of the jets. In Sco X−1, the intrinsic polarization is variable (and sometimes absent) in the H and K bands. In the J band (i.e. at higher frequencies), the polarization is not significantly variable and is consistent with an interstellar origin. The optical light from GX 339–4 is also polarized, but at a level and position angle consistent with scattering by interstellar dust. The other polarized source is SS 433, which has a low level (0.5–0.8 per cent) of J-band polarization, likely due to local scattering. The NIR counterparts of GRO J0422+32, XTE J1118+480, 4U 0614+09 and Aql X–1 (which were all in or near quiescence) have a linear polarization level of <16 per cent (3σ upper limit, some are <6 per cent). We discuss how such observations may be used to constrain the ordering of the magnetic field close to the base of the jet in such systems.