Kinematics of the jet in M87 on scales of 100 -- 1000 Schwarzschild radii

Understand

Very long baseline interferometry (VLBI) imaging of radio emission from extragalactic jets provides a unique probe of physical mechanisms governing the launching, acceleration, and collimation of relativistic outflows.

• The two-dimensional structure and kinematics of the jet in M\,87 (NGC\,4486) have been studied by applying the Wavelet-based Image Segmentation and Evaluation (WISE) method to 11 images obtained from multi-epoch Very Long Baseline Array (VLBA) observations made in January-August 2007 at 43 GHz ($\lambda = 7$ mm).
• The WISE analysis recovers a detailed two-dimensional velocity field in the jet in M\,87 at sub-parsec scales.
• The observed evolution of the flow velocity with distance from the jet base can be explained in the framework of MHD jet acceleration and Poynting flux conversion.