Stream of gas between Magellanic Clouds may come from both

Nature : The Magellanic Streamâmdash;a ribbon of gas stretching hundreds of thousands of light-years between the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC)âmdash;was first discovered in the 1970s. The gas was originally believed to have been pulled from the SMC by its larger partner. New observations by a team of astronomers led by Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland, and Philipp Richter of the University of Potsdam in Germany have given support to a competing theory: that at least some of the gas was blown into the stream by supernovae and stellar winds in the LMC. The team estimated the amounts of oxygen and sulfur throughout the stream by measuring the absorption of UV light emitted by galaxies behind the gas. They found low amounts of both elements in the majority of gas and matched the concentrations to those present in the SMC 2 billion years ago. However, the section nearest the two Magellanic Clouds has more sulfur, in concentrations similar to those currently present in the LMC. What’s more, the composition of the gas at either end of the stream does not match that of the Milky Way. The discrepancy can be accounted for if the two clouds are recently arrived members of a local group of galaxies. If the clouds had been orbiting the Milky Way for a long period, the gas in the stream would have long been displaced by gas from the Milky Way.