Distribution of gas, dust and the λ6613 Å DIB carrier in the Perseus OB2 association

We present a study of the spatial distribution of the λ6613 Å DIB carrier in the Perseus OB2 association based on high resolution observations toward lines of sight representing different interstellar environments. We determined that in the studied region, the λ6613 Å DIB carrier is concentrated in two distinct clouds with velocities of 1.4 (± 0.4) and 12.0 (± 0.9) km s^-1. We compared the λ6613 Å DIB carrier's velocity with the Na I velocity distribution derived from our survey measurements, as well as with CO, OH, H I and Ca II measurements from the literature. We conclude that the behaviour of the carrier of the λ6613 Å DIB follows the overall expansion motion of the gas in the association. The DIB velocity is directly linked to that of Ca II and H I. The DIB total column density is proportional to the total column density of Ca II and H I making those atoms good tracers of the λ6613 Å DIB carrier. Those new results support the assumption that the λ6613 Å DIB would arise from a gas phase molecule, possibly single-ionized (Sonnentrucker et al. 1997). We also conclude that the DIB carrier is distributed in shell structures over the whole association. We finally show from the DIB velocity structure that the DIB carrier, gas and dust are well mixed toward the association but that the DIB shells have an angular extent twice larger than that of the dust.