The mass distribution of dark clouds in external galaxies

By making use of published observational data on dark clouds in other galaxies, the distribution function for the cross-section of such clouds has been obtained. Models are discussed to convert to a mass distribution. If N(M)dM denotes the number of clouds with mass in the range M to M+dM, log N(M) has been plotted against log M for the clouds in each of the galaxies M31 (Andromeda), the Large Magellanic Cloud and the Small Magellanic Cloud. Because of the narrow range of cloud masses observed in the Small Magellanic Cloud, nothing can be deduced about the mass distribution in it. However, for the other two galaxies, the distribution indicates a mass function of the form N(M) proportional to Msup(-s), with the index s having a value of around 1.5 for most models. (author)