Printer Friendly

Carrying fuel into the galactic center.

Carrying fuel into the galactic center

The Milky Way galaxy, like many others, has an intensely luminous center. A team of astronomers now reports identifying a stream of gas, 15 light-years long, that appears to mark the pathway by which gas is being funneled from a giant molecular cloud toward a massive, gaseous shell surrounding the galaxy's core. This gas streamer seems to be acting as a pipeline carrying fuel from a huge reservoir to the galaxy's central "engine."

"This may be the first evidence for the feeding of gas toward the center of the galaxy," says astrophysicist Paul T.P. Ho of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Because the Milky Way's center is only about 30,000 light-years away from Earth, studying the details of its behavior provides useful clues to what may be happening in quasars and other more distant, brighter objects. Ho and his collaborators reported their discovery at this week's meeting in Boston of the American Astronomical Society.

The streamer shows up in radio signals detected at a wavelength of 1 centimeter by the Very Large Array radio telescope near Socorro, N.M. Consisting almost entirely of molecular hydrogen from a nearby cloud, the streamer feeds gas toward a dusty, rotating, gaseous shell about 6 to 10 light-years from the galactic center. The streamer's flow speeds up, from 10 to 100 kilometers per second, as the gas gets closer to the shell.

The discovery is consistent with a proposal that places a compact, extremely massive object -- possibly a supermassive black hole -- at the Milky Way's center. Matter falling through such a strong gravitational field would release tremendous amounts of energy. A gas streamer provides a means by which fresh material can be continuously fed from a nearby reservoir to the shell and then into the black hole, which acts as a powerful energy source.

"One of the key problems that we want to resolve is what happens to this gas streamer as it gets closer," Ho says. "If it is really going into the galactic center, we expect its physical condition (temperature, density and so on) to change. We're trying to piece that together."

Ho and his colleagues also have observed that the gas streamer seems to originate where a supernova remnant impinges on the molecular cloud. The explosion of a massive star may have somehow "loosened up" the cloud's edge, making it easier for the material to be drawn toward the galactic center. "You can imagine whacking the cloud on its side, causing it to puff up a little along the edge," Ho says. "The part that puffs up gets sucked in."
COPYRIGHT 1989 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:gas streamer in Milky Way
Author:Peterson, Ivars
Publication:Science News
Date:Jan 14, 1989
Previous Article:Maternal immunity via molecular ferry.
Next Article:The Martian atmosphere: old versus new.

Related Articles
The Milky Way's third population.
Turning the galaxy's heart to a watermelon.
Mapping new features of Milky Way's bulge.
Spotting the Milky Way's enigmatic center.
Radio blobs at the Milky Way's center.
COBE maps the interstellar medium.
Tuning in a mysterious radio source.
Milky Way's heart gushes antimatter.
The Milky Way's middle: getting a clear view. (Cover Story).
Mystery in the middle: a stellar riddle turns up at the Milky Way's core.

Terms of use | Copyright © 2017 Farlex, Inc. | Feedback | For webmasters