Left panel: ¹³CO J = 1−0 integrated intensity contours (blue and red) overlayed on the Spitzer-IRAC 8 μm emission map (gray scale). The blue contour levels are 20, 35, ..., 95% of the peak value (19.9 K km s^-1) integrated from 20−28 km s^-1, while the red contour levels are 20, 35, ..., 95% of the peak value (26.1 K km s^-1) integrated from 35−43 km s^-1. The different sources associated with the region are marked. The red and green stars represent the center of SNRs and PSR. The radius of the radio shell is 14′ outlined by a dashed circle. The dashed square frame marks the area observed with PMO telescope. The gray bar is in units of MJy sr^-1. Right panel: average spectra of ¹³CO J = 1−0 over the whole large-scale infrared bubble. The vertical dashed lines in the spectra mark the peak velocity.