Featured Research

from universities, journals, and other organizations

Cosmic Collisions -- European HST Scientists Catch Merging Galaxies In The Act

Date:
July 16, 1999
Source:
Space Telescope Science Institute
Summary:
Exciting new images of more than a dozen very distant colliding galaxies have been obtained by a European-led team of astronomers using the NASA/ESA Hubble Space Telescope. These colliding objects are part of a large concentration of galaxies, a galaxy cluster. Though collisions have been observed in other clusters, this particular cluster displays by far the largest number ever seen.

Exciting new images of more than a dozen very distant colliding galaxies have been obtained by a European-led team of astronomers using the NASA/ESA Hubble Space Telescope. These colliding objects are part of a large concentration of galaxies, a galaxy cluster. Though collisions have been observed in other clusters, this particular cluster displays by far the largest number ever seen. To astronomers, the finding indicates that, at least in some cases, big massive galaxies form through collisions between smaller ones, in a "generation after generation" never-ending story.

The Hubble Space Telescope studied 81 galaxies in the galaxy cluster MS1054-03, 13 of which are remnants of recent collisions or pairs of colliding galaxies. The 10-meter W.M. Keck Telescope was used to select these 81 cluster galaxies.

The cluster is 8 billion light-years away, one of the most distant known so far and thus a key target for astronomers facing the problem of how galaxies formed when the universe was young. The cluster's light has taken so long to reach us that astronomers see it now as it was when the universe was less than half its present age.

"It has been a real surprise," says team leader Pieter van Dokkum, from Groningen and Leiden universities (The Netherlands). "Collisions had never been observed before at this frequency. Many of the collisions involve very massive galaxies, and the end result will be even more massive galaxies."

Although during the collision the stars in the galaxies do not run into each other, their orbits are strongly disturbed by huge tidal forces caused by the gravitational pull. As a result, the "parent" galaxies lose their shape and smoother galaxies are formed. Clearly defined spiral galaxies, for instance, produce large featureless elliptical galaxies. The whole merging process can take less than a billion years, a relatively short time scale in astronomy.

"The Hubble image shows the paired galaxies very close together, with distorted morphologies," explains Marijn Franx, from the University of Leiden. "We can even see streams of stars being pulled out of the galaxies. They are old stars in a young galaxy."

The finding will appear in the August 1 issue of Astrophysical Journal Letters. To the authors it strongly supports a Big Bang model prediction that says that large galaxies were formed from smaller ones in many generations of mergers. It contradicts the idea that there was, in the past, a kind of 'galaxy boom' event in which all big massive galaxies were born at the same time.

As Franx states, "the evidence for the theories of galaxy formation through collisions had been strong, but circumstantial. Here we finally see a large number of galaxies caught in the act. If observed in other distant clusters, it would represent a general confirmation for a crucial aspect of our galaxy formation theories."

Collisions are much rarer today than they were in the past, but not impossible. Our own spiral galaxy, the Milky Way, is currently "eating up" several small satellite galaxies. Within 5 to 10 billion years -- some computer simulations show -- the Milky Way may collide with the Andromeda galaxy, and the result would be an elliptical galaxy.


Story Source:

The above story is based on materials provided by Space Telescope Science Institute. Note: Materials may be edited for content and length.


Cite This Page:

Space Telescope Science Institute. "Cosmic Collisions -- European HST Scientists Catch Merging Galaxies In The Act." ScienceDaily. ScienceDaily, 16 July 1999. <www.sciencedaily.com/releases/1999/07/990716072231.htm>.
Space Telescope Science Institute. (1999, July 16). Cosmic Collisions -- European HST Scientists Catch Merging Galaxies In The Act. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/1999/07/990716072231.htm
Space Telescope Science Institute. "Cosmic Collisions -- European HST Scientists Catch Merging Galaxies In The Act." ScienceDaily. www.sciencedaily.com/releases/1999/07/990716072231.htm (accessed July 25, 2014).

Share This




More Space & Time News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

This Week @ NASA, July 25, 2014

This Week @ NASA, July 25, 2014

NASA (July 25, 2014) Apollo 11 celebration, Next Giant Leap anticipation, ISS astronauts appear in the House and more... Video provided by NASA
Powered by NewsLook.com
Space to Ground: Coming and Going

Space to Ground: Coming and Going

NASA (July 25, 2014) One station cargo ship leaves, another arrives, aquatic research and commercial spinoffs. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com
How A Solar Flare Could Have Wrecked Earth's Electronics

How A Solar Flare Could Have Wrecked Earth's Electronics

Newsy (July 25, 2014) Researchers say if Earth had been a week earlier in its orbit around the sun, it would have taken a direct hit from a 2012 coronal mass ejection. Video provided by Newsy
Powered by NewsLook.com
Raw: ISS Cargo Ship Launches in Kazakhstan

Raw: ISS Cargo Ship Launches in Kazakhstan

AP (July 23, 2014) The Progress 56 cargo ship launched from the Baikonur Cosmodrome in Kazakhstan Wednesday. NASA says it will deliver cargo and crew supplies to the International Space Station. (July 23) 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