Broadband Metric-Range Radio Emission Associated with a Moreton/EIT Wave

Abstract

We present the evolution and kinematics of a broadband radio source that propagated collaterally with an Hα/EIT wave, linking it with the type II burst that was excited higher up in the corona. The NRH wave emission extended from the frequency f ≈ 327 to f < 151 MHz and was considerably weaker than the flare-related type IV burst. The emission centroid propagated at a height of 0-200 Mm above the solar limb and was intensified when the disturbance passed over enhanced coronal structures. We put forward the ad hoc hypothesis that the NRH wave signature is optically thin gyrosynchrotron emission excited by the passage of the coronal MHD fast-mode shock. The identification of radio emission associated with the coronal wave front is important since it offers us new diagnostic information that could provide us with better insight into the physical conditions in the disturbance itself. © 2005. The American Astronomical Society. All rights reserved.