Featured Research

from universities, journals, and other organizations

Astronomers Find Galactic Collisions More Common Than Previously Thought

Date:
January 6, 1999
Source:
Iowa State University
Summary:
Collisions between galaxies that include billions of stars like our Sun, have happened more frequently than previously thought, according to a team of Iowa State University astronomers. In addition, these galactic collisions apparently have helped shape the properties of the current universe, said Russ Lavery, an assistant professor of physics and astronomy and leader of the research team.

AMES, Iowa -- Collisions between galaxies that include billions of stars like our Sun, have happened more frequently than previously thought, according to a team of Iowa State University astronomers. In addition, these galactic collisions apparently have helped shape the properties of the current universe, said Russ Lavery, an assistant professor of physics and astronomy and leader of the research team.

Lavery and graduate students Michael Reed and Anthony Remijan (now at the University of Illinois) examined random images from the Hubble Space Telescope and looked for ring galaxies, a specific type of galaxy that is the product of galactic collisions. Collisional ring galaxies result when a small galaxy passes almost directly through the center of a spiral galaxy.

The result is a galaxy with a distinctive ring-like structure of intense star formation at its outer edges. A well-known example is the "Cartwheel" galaxy, located about 500-million light-years from Earth in the constellation of Sculptor. (A light year is the distance light travels in a year, about 6 trillion miles).

"We have looked at about 100 Hubble images and we expected to find maybe one ring galaxy among them," Lavery said. "Instead we've identified 20 ring galaxies."

Lavery presented the team's research results today (Jan. 6) at the annual meeting of the American Astronomical Society in Austin, Tex., (Jan. 5-9, 1999).

The ISU-lead project tries to identify distant ring galaxies in deep space images obtained with the fixed Wide Field/Planetary Camera (WFPC2) on the Hubble Space Telescope. These images are available through the Space Telescope Science Institute Archives program. The Hubble Space Telescope orbits Earth providing unprecedented views of astronomical objects. Hubble images have allowed these astronomers to identify ring galaxies out to a redshift of 1, equivalent to a distance of about 8-billion light-years.

Lavery plans to analyze more than 500 images from the Hubble to provide a more representative survey of the sky. But already the team is finding some surprising results.

"The images we examined were random, suggesting that galactic collisions have happened all around the Universe," Lavery explained. "This coupled with the fact that we see more of these types of galaxies the farther we look into space, and thus back into time, suggest that collisional galaxies have played a major role in determining the types of galaxies we observe around us today."

The Iowa State team's results support the earlier work of Alar Toomre of the Massachusetts Institute of Technology, Cambridge, and Francois Schweizer of the Carnegie Institution of Washington, D.C. Both have stressed the importance of mergers of galaxies in forming large elliptical galaxies. If interactions between galaxies were much more frequent, it is quite likely that the rate at which galaxies merged was also much more frequent and could have produced many of the large elliptical galaxies in the present day universe, Lavery explained.

The Iowa State astronomers focused on the distinctive ring galaxies for their studies because these galaxies are relatively easy to identify. Lavery adds that the powerful Hubble Space Telescope played a key role in obtaining images that are not possible from Earth-based telescopes.

The study of ring galaxies is also being undertaken by other Iowa State astronomical teams. Astronomers Phil Appleton and Curt Struck have for several years examined the Cartwheel galaxy and other ring galaxies searching for clues about how stars are born, how they evolve and how they die. The Hubble Space Telescope is operated for NASA by the Association of Universities for Research in Astronomy. Iowa State University is a member of AURA.

- 30 -

Editors: Some of the images Russ Lavery has obtained of collisional ring galaxies can be viewed at http://www.public.iastate.edu/~lavery/Researchstuff/dirRings/ringshst.html


Story Source:

The above story is based on materials provided by Iowa State University. Note: Materials may be edited for content and length.


Cite This Page:

Iowa State University. "Astronomers Find Galactic Collisions More Common Than Previously Thought." ScienceDaily. ScienceDaily, 6 January 1999. <www.sciencedaily.com/releases/1999/01/990106080913.htm>.
Iowa State University. (1999, January 6). Astronomers Find Galactic Collisions More Common Than Previously Thought. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/1999/01/990106080913.htm
Iowa State University. "Astronomers Find Galactic Collisions More Common Than Previously Thought." ScienceDaily. www.sciencedaily.com/releases/1999/01/990106080913.htm (accessed September 18, 2014).

Share This



More Space & Time News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boeing, SpaceX to Send Astronauts to Space Station

Boeing, SpaceX to Send Astronauts to Space Station

AFP (Sep. 17, 2014) — NASA selected Boeing and SpaceX on Tuesday to build America's next spacecraft to carry astronauts to the International Space Station (ISS) by 2017, opening the way to a new chapter in human spaceflight. Duration: 01:13 Video provided by AFP
Powered by NewsLook.com
East Coast Treated To Rare Meteor Sighting

East Coast Treated To Rare Meteor Sighting

Newsy (Sep. 16, 2014) — Numerous residents along the East Coast reported seeing a bright meteor flash through the sky Sunday night. Video provided by Newsy
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) — Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
NASA Picks Boeing and SpaceX to Ferry Astronauts

NASA Picks Boeing and SpaceX to Ferry Astronauts

AP (Sep. 16, 2014) — NASA is a giant step closer to launching Americans again from U.S. soil. It has announced it has picked Boeing and SpaceX to transport astronauts to the International Space Station in the next few years. (Sept. 16) Video provided by AP
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