SS433's jet trace from ALMA imaging and Global Jet Watch spectroscopy: evidence for post-launch particle acceleration

Abstract

We present a comparison of Doppler-shifted H-alpha line emission observed by the Global Jet Watch from freshly-launched jet ejecta at the nucleus of the Galactic microquasar SS433 with subsequent ALMA imaging at mm-wavelengths of the same jet ejecta. There is a remarkable similarity between the transversely-resolved synchrotron emission and the prediction of the jet trace from optical spectroscopy: this is an a priori prediction not an a posteriori fit, confirming the ballistic nature of the jet propagation. The mm-wavelength of the ALMA polarimetry is sufficiently short that the Faraday rotation is negligible and therefore that the observed E-vector directions are accurately orthogonal to the projected local magnetic field. Close to the nucleus the B-field vectors are perpendicular to the direction of propagation. Further out from the nucleus, the B-field vectors that are coincident with the jet instead become parallel to the ridge line; this occurs at a distance where the jet bolides are expected to expand into one another. X-ray variability has also been observed at this location; this has a natural explanation if shocks from the expanding and colliding bolides cause particle acceleration. In regions distinctly separate from the jet ridge line, the fractional polarisation approaches the theoretical maximum for synchrotron emission.

arXiv commentTo appear in ApJ Letters

References in corpus (13)

• A multi-scale multi-frequency deconvolution algorithm for synthesis imaging in radio interferometry
• Symmetry in the changing jets of SS433 and its true distance from us
• Iron Emission Lines from Extended X-ray Jets in SS 433: Reheating of Atomic Nuclei
• Twenty Years of Timing SS433
• The Distance to SS433/W50 and its Interaction with the ISM
• ALMA Science Verification Data: Millimeter Continuum Polarimetry of the Bright Radio Quasar 3C 286
• Fast launch speeds in radio flares, from a new determination of the intrinsic motions of SS 433's jet bolides
• Rapid variability of the arcsec-scale X-ray jets of SS 433
• Jet velocity in SS433: its anti-correlation with precession-cone angle and dependence on orbital phase
• SS433's accretion disc, wind and jets: before, during and after a major flare
• Coupled radio and X-ray emission and evidence for discrete ejecta in the jets of SS 433
• Structure and Magnetic Fields in the Precessing Jet System SS 433 I. Multi-Frequency Imaging from 1998
• The human pipeline: distributed data reduction for ALMA

Cited by in corpus (6)

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• Energy estimation of high energy particles associated with the SS433/W50 system through radio observation at 1.4 GHz
• The precessing jets of classical nova YZ Reticuli
• PeV particle acceleration and non-thermal emission in the `minimalist' model of the extended jets in W50/SS433
• Discovery of CO Clouds Associated with the X-ray Jets of SS 433: Evidence for Shock-Cloud Interaction Enhancing Nonthermal X-ray Emission