Distant Colliding Galaxies
A number of us here at UVic are involved in a study of distant
galaxies. We have specifically targeted galaxies which are
several billion light years away from us. In order to obtain detailed
information about these galaxies, we have used the
Canada-France-Hawaii Telescope, which is located on the top of
Mauna Kea, on the Big Island of Hawaii. We have identified many
thousands of galaxies. Following is a colour-composite of one
of our images. To see more detail, please click on the image.
One of the many goals of this galaxy survey is to investigate the
importance of galaxy collisions in the universe.
Using these images, along with information obtained from taking
spectra of about 5,000 galaxies, we have identified many cases of
galaxies undergoing collisions. We find that galaxy collisions are
more common in the distant universe than nearby.
This means that collisions occurred more frequently when the
universe was younger. This is due, in part, to the fact that the
universe was more dense back then, and has been expanding ever since.
Some images of these distant galaxy collisions follow.
- This pair of spiral galaxies appear to be undergoing a close
encounter. These galaxies are approximately 1 billion light years
away from us. These galaxies were found on the big colour image near
the top of this page. Can you find them?
- This close galaxy pair is roughly 3 billion
light years away from us, and the galaxies are separated from each
other by about 30,000 light years. These galaxies were
found to be unusually blue, with strong spectral emission lines.
It appears that these galaxies are in the process of merging,
which may be triggering the formation of a new generation of stars.
-
Here is a mosaic of 12 additional close galaxy pairs. The images are
negatives, to aid in the identification of faint features. In each case, the
galaxies are known to lie at approximately the same distance from us.
This confirmation is only possible using galaxy spectra. This is
currently the largest sample of confirmed close pairs ever found in
the distant universe. We expect to find about 100 more close pairs
by the time our survey has been completed.
- Please see
my current webpage
for more information on this on-going investigation, including
follow-up observations with the
Hubble Space Telescope.
