Featured Research

from universities, journals, and other organizations

Clue to origin of Milky Way gas clouds discovered

Date:
May 29, 2010
Source:
National Radio Astronomy Observatory
Summary:
A study of hydrogen gas clouds in two different regions of the Milky Way shows that they are much more abundant above areas of intense star formation, indicating they are blown away from the Galaxy's plane by stellar winds and supernova explosions.

Artist's conception shows Milky Way regions studied, with hydrogen clouds more abundant in region above area where central bar merges with spiral arm. Bright point at bottom center is location of our Solar System.
Credit: Bill Saxton, NRAO/AUI/NSF

A surprising discovery that hydrogen gas clouds found in abundance in and above our Milky Way Galaxy have preferred locations has given astronomers a key clue about the origin of such clouds, which play an important part in galaxy evolution.

"We've concluded that these clouds are gas that has been blown away from the Galaxy's plane by supernova explosions and the fierce winds from young stars in areas of intense star formation," said H. Alyson Ford of the University of Michigan, whose Ph.D thesis research from Swinburne University formed the basis for this result. The team, consisting of Ford and collaborators Felix J. Lockman, of the National Radio Astronomy Observatory (NRAO), and Naomi Mclure-Griffiths of CSIRO Astronomy and Space Science, presented their findings to the American Astronomical Society's meeting in Miami, Florida.

The astronomers studied gas clouds in two distinct regions of the Galaxy. The clouds they studied are between 400 and 15,000 light-years outside the disk-like plane of the Galaxy. The disk contains most of the Galaxy's stars and gas, and is surrounded by a "halo" of gas more distant than the clouds the astronomers studied.

"These clouds were first detected with the National Science Foundation's Robert C. Byrd Green Bank Telescope, and are quite puzzling. They are in a transitional area between the disk and the halo, and their origin has been uncertain," Lockman explained. The research team used data from the Galactic All-Sky Survey, made with CSIRO's Parkes radio telescope in Australia.

When the astronomers compared the observations of the two regions, they saw that one region contained three times as many hydrogen clouds as the other. In addition, that region's clouds are, on average, twice as far above the Galaxy's plane.

The dramatic difference, they believe, is because the region with more clouds lies near the tip of the Galaxy's central "bar," where the bar merges with a major spiral arm. This is an area of intense star formation, containing many young stars whose strong winds can propel gas away from the region. The most massive stars also will explode as supernovae, blasting material outward. In the other region they studied, star formation activity is more sparse.

"The properties of these clouds show clearly that they originated as part of the Milky Way's disk, and are a major component of our Galaxy. Understanding these clouds is important in understanding how material moves between the Galaxy's disk and its halo, a critical process in the evolution of galaxies," Lockman said.

The clouds consist of neutral hydrogen gas, with an average mass equal to that of about 700 Suns. Their sizes vary greatly, but most are about 200 light-years across. The astronomers studied about 650 such clouds in the two widely-separated regions of the Galaxy.

The Parkes Radio Telescope is part of the Australia Telescope, which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.


Story Source:

The above story is based on materials provided by National Radio Astronomy Observatory. Note: Materials may be edited for content and length.


Cite This Page:

National Radio Astronomy Observatory. "Clue to origin of Milky Way gas clouds discovered." ScienceDaily. ScienceDaily, 29 May 2010. <www.sciencedaily.com/releases/2010/05/100526111230.htm>.
National Radio Astronomy Observatory. (2010, May 29). Clue to origin of Milky Way gas clouds discovered. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2010/05/100526111230.htm
National Radio Astronomy Observatory. "Clue to origin of Milky Way gas clouds discovered." ScienceDaily. www.sciencedaily.com/releases/2010/05/100526111230.htm (accessed September 1, 2014).

Share This




More Space & Time News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: NASA Captures Solar Flare

Raw: NASA Captures Solar Flare

AP (Sep. 1, 2014) NASA reported the sun emitted a mid-level solar flare, on August 24th. NASA's Solar Dynamics Observatory captured the images of the flare, which erupted on the left side of the sun. (Sept. 1) Video provided by AP
Powered by NewsLook.com
Space Shuttle Discovery's Legacy, 30 Years Later

Space Shuttle Discovery's Legacy, 30 Years Later

Newsy (Aug. 30, 2014) The space shuttle Discovery launched for the very first time 30 years ago. Here's a look back at its legacy. Video provided by Newsy
Powered by NewsLook.com
Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins