Mapping and multi-wavelength properties of stellar complexes in the LMC

Abstract

Filamentary structures of early type stars are found to be a common feature of the Magellanic Clouds formed at an age of about 0.9 – 2 × 108yr. As we go to younger ages these large structures appear fragmented and sooner or later form young clusters and associations. In the optical domain we have detected 56 such large structures of young objects, known as stellar complexes in the LMC for which we give coordinates and dimensions. IR properties of these regions have been investigated using IRAS data. The colour‐magnitude diagram (CMD) and two‐colour diagrams from IRAS data of these regions have been compared with observations of starburst galaxies. It has been found that nearly 1/3 of the stellar complexes are extremely active resembling the IR behaviour of starburst galaxies and H II regions. These stellar complexes illustrating such properties are called here “starburst regions”. They host an increased number of H II regions and SNRs. The main starburst tracers are their IR luminosity (F60 well above 5.4 Jy) and the 8.6‐GHz radio emission. Finally the evolution of all stellar complexes is discussed based on the CO emission.