River of hydrogen flowing through space discovered

Researchers using Green Bank Telescope have discovered what could be a never-before-seen river of hydrogen flowing through space.

The very faint, very tenuous filament of gas is streaming into the nearby galaxy NGC 6946 and may help explain how certain spiral galaxies keep up their steady pace of star formation.

Astronomer D. J. Pisano from West Virginia University said that they knew that the fuel for star formation had to come from somewhere., asserting that so far, however, they've detected only about 10 percent of what would be necessary to explain what we observe in many galaxies.

He said that a leading theory is that rivers of hydrogen - known as cold flows - may be ferrying hydrogen through intergalactic space, clandestinely fueling star formation.

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 fueling the sustained star formation in this and similar spiral galaxies.

Using the GBT, Pisano was able to detect the glow emitted by neutral hydrogen gas connecting NGC 6946 with its cosmic neighbors.

Astronomers have long theorized that larger galaxies could receive a constant influx of cold hydrogen by syphoning it off other less-massive companions.

The results have been published in the Astronomical Journal.