SOHO/EIT observations of the 1997 April 7 coronal transient: Possible evidence of coronal Moreton waves

We report observations obtained with the Extreme ultraviolet Imaging Telesc ope (EIT) on board SOHO of a large-scale coronal transient propagating acro ss the disk of the Sun at a speed of 250 km s(-1), in apparent association with a flare and coronal mass ejection. The observations consist of a serie s of images taken in the Fe XII 195 A bandpass at an average cadence of 15 minutes. A visible increase in coronal emission propagates away from the er upting region, traveling across most of the solar disk in less than an hour . As the wave propagates through the ambient corona, its path is not homoge neous, and it is less observable near strong magnetic features such as acti ve regions and magnetic neutral lines. The characteristics of this event ap pear to be representative of several other "EIT waves," which we identify a s strong candidates for the coronal manifestation of Moreton waves.