Flowchart of our Gaussian fitting procedure with N components.Gaussian fitting with N = 1 component is first applied to each pixel. Where the S/N of the residual peak intensity is lower than 5, we considered that the spectrum at this pixel consists of N = 1 Gaussian component. When the S/N of the residual peak intensity is higher than 5, we applied Gaussian fitting with N + 1 Gaussian components. This process was repeated for five components at most. Then, when the peak velocity is lower than 4.0 km s⁻¹ or higher than 7.0 km s⁻¹, we considered that the component is not associated with the B211/B213 cloud and subtracted it from the data cube.