the interior of the source; (3) a small ($30''$), bright (green) filament along the outer boundary of the source in the SE; (4) another small, faint filament outside the NE bounday of the source. Overall the filaments are located either within the radio shell or inside of the source, while the filaments are along the radio boundary or even outside of it. We have not found any apparent filament in our rather shallow imaging observation, although we have detected faint line emission toward the peak position in our spectroscopic observation. In the following, we summarize the results on the and emission features.

164 emission
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### Photometry

In order to see the emission features more clearly, we have produced an ‘star-subtracted’ image (Fig. 2). We first performed PSF photometry of H-cont and 164 images, and removed stars in the 164 image if they had corresponding ones in the H-cont image. This PSF photometric subtraction left residuals around bright stars which we masked out. The faint stars, which were not removed by the PSF subtraction because the H-cont image is not as deep as that of , were then removed by subtraction of median value of $15 \times 15$ nearby pixels. 