The Tadpole, however, is not in the news today. But it does sort of relate
to the final chapter of a story told by another pair of galaxies in the image.
Astronomers found something interesting going on with the bright spiral galaxy
that sits, tilted at an angle, near the lower left of the image.
The spiral, which looks comparatively small here, is farther away than the
Tadpole and so is actually of a common, standard size. It, too, has a companion
galaxy, one called a dwarf that it has just begun consuming. Tethering the two
is a stream of stars pulled out from the dwarf companion by the spiral galaxy's
more powerful gravity.
You
can't see the faint stream of stars in the main image, but it's visible in this
close-up (in which the spiral galaxy has been tilted a different direction by
the researchers, perhaps just to confuse you). The stream was enhanced through
computer modeling to make it even more apparent (and you can see that stuff
here).
The scene is cited as evidence for galaxy gobbling, and it is one of the earliest
stages of the process ever photographed.
"Although long predicted, direct evidence for plumes of stars being ripped
from a dwarf galaxy as it is swallowed up by a giant galaxy has remained elusive,"
said Duncan Forbes, an astronomer at Swinburne University of Technology in Australia
who led the investigation. "This discovery provides the best evidence to date,"
Our own Milky Way Galaxy is thought to have built its bulk in part by swallowing
smaller galaxies, and it is still doing so. The new study was detailed yesterday
in the online version of the journal Science.
