Hα core intensity map taken at 500 s after the start of observations. The dashed arrows indicate the two main slits (FIL and ARC) and the two auxiliary slits (FIL2 and ARC2). The cyan-colored and magenta-colored contours represent ±1σ levels of offband intensity at −1.5 Å, and the plus symbol marks the center of the offband bright concentration co-spatial with the magnetic concentration of positive polarity.