Astronomers analyzed a sample of galaxies that suddenly “turned on” their radio emissions. In most cases, this means that their supermassive black hole began accreting matter more intensely and triggered a faint jet, but a few objects behave differently. Their galaxies are actively forming stars, the black holes are smaller, infrared flares appear, and the pattern of changes in radio emissions resembles known cases of a star being consumed by a black hole. The authors of this article suggest that some radio transient phenomena may in fact be cases of a star being torn apart and swallowed by a supermassive black hole, and that the WISE W3–radio ratio may prove to be a new way to distinguish them.
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