Velocities and Temperatures of an Ellerman Bomb and Its Associated Features

Abstract

We investigated the velocity and temperature characteristics of an Ellerman bomb (EB) and its associated features based on observations made with the Fast Imaging Solar Spectrograph (FISS) and a broadband TiO filter of the 1.6 meter New Solar Telescope at Big Bear Solar Observatory. In the TiO images of the photospheric level, we found a granular cell expanding in two opposite directions near the site of the EB. When one end of this granule reached the EB site, the transverse speed of the tip of the expanding granule rapidly decreased and the EB brightened. The wings of the Hα profile of the EB indicated that the EB was blueshifted up to 7 km s−1. About 260 s after the EB brightening, a surge was seen in absorption and varied from a blueshift of 20 km s−1 to a redshift of 40 km s−1 seen in the Hα and Ca ii 8542 A lines. From the Doppler absorption width of the two lines determined by applying the cloud model, we estimated the mean temperature of the surge material to be about 29000 K and the mean speed of nonthermal motion to be about 11 km s−1. We discuss the physical implications of our results in terms of magnetic reconnection and processes related to it.