An international research team lead by Dr. Tamura (Nobeyama Radio Observatory, NAOJ) discovered a cluster of bright submillimeter galaxies forming stars at an extraordinary high rate. The researchers call them as "monster galaxies", because their star formation rates are estimated nearly 1000 times higher than that of the Milky Way Galaxy. Such galaxies of extremely high star formation rates were detected independently. This research, for the first time, reported clustered monster galaxies.

A new camera installed on ASTE (Atacama Submillimeter Telescope Experiment) were used for this research. The cluster of submillimeter galaxies was located on the constellation of Aquarius. Previous observations by Subaru Telescope for the same region had revealed that there was a cluster of relatively small galaxies known as Lyman-alpha emitters. The astronomers found spacial correlation of the densities between the Lyman-alpha emitters and the monster galaxies. The newly discovered cluster was located on the regions where the density of the Lyman-alpha emitters is higher. Higher density of galaxies means higher density of the dark matter.

A today's theory on galaxy formation predicts that very active star formation occurs at the peak of dark matter density to evolve to a massive galaxy. This research was consistent with the view of such galaxy formation theory.

The research team are carrying out more large-scale survey of submillimeter galaxies. Their project is expected to answer the questions below; (1) are submillimeter galaxies always located on the density peak of visible galaxies such as Lyman-alpha emitters?; (2) when submillimeter galaxies formed?; (3) the submillimeter galaxies evolve to today's massive galaxies; (4) how today's massive galaxies formed.

The research was published on Issue of 7th May, Nature.

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More info: Press release web page (Japanese only)