WASHINGTON (TIP): Astronomers have discovered a never-beforeseen river of hydrogen flowing through space into a nearby galaxy around 22 million light years from Earth.
This very faint, very tenuous filament of gas is streaming into the galaxy NGC 6946 and may help explain how certain spiral galaxies keep up their steady pace of star formation, researchers said. “We knew that the fuel for star formation had to come from somewhere.
So far, however, we’ve detected only about 10% of what would be necessary to explain what we observe in many galaxies,” astronomer DJ Pisano from West Virginia University said. “A leading theory is that rivers of hydrogen – known as cold flows may be ferrying hydrogen through intergalactic space, fuelling star formation.
But this was too diffused to detect, until now,” he said. Spiral galaxies, like our own Milky Way, typically maintain a rather tranquil but steady pace of star formation. Others, like NGC 6946, which is located approximately 22 million light years from Earth on the border of the constellations Cepheus and Cygnus, are much more active, though less-so than more extreme starburst galaxies. This raises the question of what is fuelling the sustained star formation in this and similar spiral galaxies.