The Herschel Heritage survey aims to look at the links between dust and star formation processes with detailed studies of the Milky Way galaxy’s nearest neighbours – the Large and Small Megallanic Clouds. These are two dwarf irregular galaxies that orbit around our own galaxy, and are thus ideal laboratories for looking at galaxy scale processes. It’s difficult to do this in our own galaxy because we’re inside it, and thus can’t clearly see how it is structured.
For their Science Demonstration observations Heritage obtained a scan across the centre of the Large Magellanic Cloud. The cool dust revealed by Herschel can then be matched to observations at other wavelengths with, for example, the Spitzer satellite, that reveal other constituents of the interstellar medium in the LMC.
From this image we can see several things. Firstly, stars are generally found away from regions of cool interstellar dust. Secondly, dust and massive star formation are frequently associated. However, some large clumps of dust do not have attendant star formation. Why is this? Are these regions pregnant with potential young stars awaiting some yet-to-be-identified trigger, or is there some ingredient missing in them that’s preventing star formation? Further observations with Herschel, and especially spectroscopy which will allow the determination of the detailed properties of the gas in these various different clumps, should answer this question.