A catalogue of Spitzer dark clouds

Therefore a comprehensive view of star formation requires understanding the initial conditions for cluster formation. The goal of our study is to shed light on the physical properties of infrared dark clouds (IRDCs) and the role they play in the formation of stellar clusters.

This article, the first of a series dedicated to the study of IRDCs, describes techniques developed to establish a complete catalogue of Spitzer IRDCs in the Galaxy. We have analysed Spitzer GLIMPSE and MIPSGAL data to identify a complete sample of IRDCs in the region of Galactic longitude and latitude 10{deg}<|l|<65{deg} and |b|<1{deg}. From the 8um observations we have constructed opacity maps and used a newly developed extraction algorithm to identify structures above a column density of N_H2_=1x10^22^cm^-2^.