North-south asymmetry in the solar coronal rotation

Abstract

The solar images at 17 GHz by the Nobeyama Radio Heliograph and in X-rays by the soft X-ray telescope (SXT) on board the Yohkoh satellite have been of particular interest for the estimation of solar coronal rotation using the flux modulation approach. These studies established that the solar corona rotates differentially. The radio images estimate an equatorial rotation period lower than those estimated by the X-ray images. The latitude profiles of the coronal rotation have temporal variability. It is very interesting that the space-time plots of sidereal rotation period clearly reveal north-south (NS) asymmetry. The asymmetry appears to change its sign in odd and even activity cycles of the Sun. © 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS.