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Molecular Gas in the Wind of the Starburst Galaxy M82

In galaxies, molecular clouds are reservoirs from which new stars are born. Massive stars eject stellar winds and explode as supernovae. The ejected material contributes fresh gas supply for further star formation. In some galaxies, called starbursts, rapid consumption of molecular gas leads to the phenomenon known as galactic wind: stellar winds and supernova explosions occur within only several million years, heat the ambient gas, and in synergy with radiation pressure from luminous star clusters, trigger outflow of gas and dust from the host galaxy. If most of the gas is blown out, star formation runs out of fuel. In other words, galactic winds can suppress star formation, which is essential in galaxy evolution.

M82 is one such nearby starburst galaxy. Researchers from Tsukuba University have observed the outflow of molecular gas from M82 with the NRO 45-m telescope. They found that nearly 1 billion solar mass equivalent of molecular gas is blown out from the galaxy at a speed of 200 km/s more than 6000 light years into the galactic halo. The outflow energy can be related to the energy released in supernova explosions.

Reference: Salak et al. (2013) PASJ 65, 66 

Figure: Contours of CO emission (molecular gas distribution) superimposed on an optical (Hα) image of M82. The molecular-gas outflow is indicated by arrows. (Optical image: Mutchler et al. 2007, PASP, 119, 1; The Hubble Heritage Team)