Featured Research

from universities, journals, and other organizations

Next-door Cosmic Encounter: Neighboring Galaxies Collided 2-3 Billion Years Ago

Date:
September 5, 2009
Source:
Queen's University
Summary:
An international team of astronomers has uncovered evidence of a nearby cosmic encounter. Their study indicates that the Andromeda and Triangulum galaxies, the two galaxies closest to our own, collided about two to three billion years ago.

The possible orbit of the Triangulum galaxy around Andromeda.
Credit: Image courtesy of Queen's University

An international team of astronomers, including Queen’s University physicist Larry Widrow, have uncovered evidence of a nearby cosmic encounter. Their study indicates that the Andromeda and Triangulum galaxies, the two galaxies closest to our own, collided about two to three billion years ago.

“The encounter forever changed the structure of the galaxies,” says Dr. Widrow, a professor of Physics, Engineering Physics and Astronomy at Queen’s. “The collision between the galaxies appears to have caused millions of stars to be ripped from the Triangulum disk to form a faint stream visible in the PAndAS data.”

Dr. Widrow, along with John Dubinsky of the University of Toronto, recreated this galactic encounter using a high performance computer and theoretical modeling. Their simulations illustrate how the strong gravitational field of Andromeda could have pulled stars away from the Triangulum disk creating a stream just as the team saw.

The Pan-Andromeda Archeological Survey (PAndAS), led by Alan McConnachie of the Herzberg Institute of Astrophysics in Victoria BC, is using the Canada-France-Hawaii telescope to map the Andromeda and Triangulum galaxies. This map, the largest of its kind, will allow astronomers to test the hypothesis that galaxies grow by “cannibalizing” other galaxies.

The findings from the first year of the survey are published this week in the journal Nature.

Galaxies are large collections of stars, often distributed in a disk-like pattern with spiral arms. Nearly 40 years ago, astronomers learned that galaxies are embedded in extended halos of dark matter.

“Our observations now show that stars also inhabit these outer halos,” says Dr. Widrow. “We believe that these stars are relics of small galaxies that were destroyed by the powerful tidal fields of a larger galaxy. Our observations also suggest that the Triangulum Galaxy is being ripped apart by Andromeda.”

Andromeda, and our own galaxy the Milky Way, are the two largest members of a small cluster of galaxies known as the Local Group. Triangulum, the third largest member of the Local Group, is about one-tenth the size of Andromeda.

“Within a few billion years Triangulum will be completely destroyed by Andromeda and its stars will be dispersed throughout the Andromeda halo,” says Dr. Widrow. “And a few billion years after that, Andromeda and the Milky Way will collide and merge together to form a giant elliptical galaxy.”

Dr. Widrow is funded by a Discovery Grant with the Natural Sciences and Engineering Research Council of Canada (NSERC).


Story Source:

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


Journal Reference:

  1. Alan W. McConnachie, Michael J. Irwin, Rodrigo A. Ibata, John Dubinski, Lawrence M. Widrow, Nicolas F. Martin, Patrick C๔t้, Aaron L. Dotter, Julio F. Navarro, Annette M. N. Ferguson, Thomas H. Puzia, Geraint F. Lewis, Arif Babul, Pauline Barmby, Olivier Bienaym้, Scott C. Chapman, Robert Cockcroft, Michelle L. M. Collins, Mark A. Fardal, William E. Harris, Avon Huxor, A. Dougal Mackey, Jorge Pe๑arrubia, R. Michael Rich, Harvey B. Richer, Arnaud Siebert, Nial Tanvir, David Valls-Gabaud & Kimberly A. Venn. The remnants of galaxy formation from a panoramic survey of the region around M31. Nature, 2009; 461 (7260): 66 DOI: 10.1038/nature08327

Cite This Page:

Queen's University. "Next-door Cosmic Encounter: Neighboring Galaxies Collided 2-3 Billion Years Ago." ScienceDaily. ScienceDaily, 5 September 2009. <www.sciencedaily.com/releases/2009/09/090904165246.htm>.
Queen's University. (2009, September 5). Next-door Cosmic Encounter: Neighboring Galaxies Collided 2-3 Billion Years Ago. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2009/09/090904165246.htm
Queen's University. "Next-door Cosmic Encounter: Neighboring Galaxies Collided 2-3 Billion Years Ago." ScienceDaily. www.sciencedaily.com/releases/2009/09/090904165246.htm (accessed April 16, 2014).

Share This



More Space & Time News

Wednesday, April 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Baby Moon 'Peggy' Spotted In Saturn's Rings

New Baby Moon 'Peggy' Spotted In Saturn's Rings

Newsy (Apr. 15, 2014) — A bump in the rings could be a half-mile-wide miniature moon. It was found by accident in Cassini probe images. Video provided by Newsy
Powered by NewsLook.com
Americas Glimpse Total Lunar Eclipse

Americas Glimpse Total Lunar Eclipse

AFP (Apr. 15, 2014) — A total lunar eclipse, the first since December 2011, took place early Tuesday morning with the Americas getting the best glimpse. Duration: 1:19 Video provided by AFP
Powered by NewsLook.com
NASA Showcases Lunar Eclipse

NASA Showcases Lunar Eclipse

AP (Apr. 15, 2014) — Star gazers in parts of North and South America got a rare treat early Tuesday morning - a total eclipse of the moon. (April 15) Video provided by AP
Powered by NewsLook.com
Spacecrafts Could Use Urine As Fuel Source

Spacecrafts Could Use Urine As Fuel Source

Newsy (Apr. 15, 2014) — New research says the urea from urine could be recycled for fuel. Urea is filtered out of wastewater when making drinking water. 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