An ALMA archival study of the clump mass function in the Large Magellanic Cloud

We present 1.3 and 3.2 mm continuum maps of three star-forming regions in the Large Magellanic Cloud (LMC) observed with the Atacama Large Millimeter/Submillimeter Array (ALMA). The data were taken from two projects retrieved from the ALMA public archive and from one project observed specifically for this work. We develop a technique to combine maps at these wavelengths to estimate dust-only emission corrected for free-free emission contamination. From these observations, we identify 32 molecular clumps in the LMC and estimate their total mass from their dust emission to range from 205 to 5740 M-circle dot. We derive a cumulative clump mass function (N(>= M) proportional to M alpha + 1) and fit it with a double power law to find alpha(low) = -1.76(-0.05)(+0.04), alpha(high) = -3.3 +/- 0.2, with a break mass of 2500(-200)(+300) M-circle dot. A comparison with the 30 Doradus-10 mass function derived previously from CO (2-1) data reveals a consistent range of clump masses and good agreement between the fitted slopes. We also find that the low-mass index of the LMC mass function agrees well with the high-mass index for core and clump mass functions from several star-forming regions in the Milky Way. This agreement may indicate an extension of the Milky Way power law to higher masses than previously observed.