Infrared dark cloud complex 38.94-00.46 at the distance of D_fg = 2.7 kpc (estimated from foreground source density, see Sect. 3). Top row: the first panel shows NIR dust extinction map, derived using JHK_S data from the UKIDSS Galactic Plane Survey. The resolution of the map is 30″ and contours starting from A_V = 3 mag in steps of 4 mag are shown. The second panel shows the integrated intensity of the ¹³CO molecule from the GRS survey data. The contours start from 15 K km s^-1 and the step is 15 K km s^-1. The velocity region included in this map is 35.1–45.7 km s^-1. The third panel shows an 8 μm optical depth map of the complex, constructed from the opacity maps of  ~ 20 individual IRDCs identified in this region by Peretto & Fuller (2009). The color scale is linear, starts from A_V ≈ 10 mag, and the maximum is A_V ≈ 90 mag. The fourth panel shows the 870 μm dust emission from the region mapped by the ATLASGAL survey (Schuller et al. 2009). The color scale is linear and starts at A_V ≈ 3.6 mag, and the maximum is A_V ≈ 43 mag. Lower left: Spitzer/GLIMPSE/MIPSGAL three-color image of the complex, showing 4.5, 8, and 24 μm data in blue, green, and red, respectively. Lower right: position-velocity diagram of the region, integrated over  − 00°45′ < b < 0°. The velocity interval chosen to represent the complex is indicated with dotted white lines.