Something appears to be peering through a shiny red mask, in this new
false-colored image from NASA's Spitzer Space Telescope. The mysterious
blue eyes are actually starlight from the cores of two merging galaxies,
called NGC 2207 and IC 2163. The mask is the galaxies' dusty spiral arms.
NGC 2207 and IC 2163 recently met and began a sort of gravitational tango
about 40 million years ago. The two galaxies are tugging at each other,
stimulating new stars to form. Eventually, this cosmic ball will come to
an end, when the galaxies meld into one. The dancing duo is located 140
million light-years away in the Canis Major constellation.
The Spitzer image reveals that the galactic mask is adorned with strings
of pearl-like beads. These dusty clusters of newborn stars, called "beads
on a string" by astronomers, appear as white balls throughout the arms of
both galaxies. They were formed when the galaxies first interacted,
forcing dust and gas to clump together into colonies of stars.
This type of beading has been seen before in other galaxies, but it took
Spitzer's infrared eyes to identify them in NGC 2207 and IC 2163. Spitzer
was able to see the beads because the stars inside heat up surrounding
dust, which then radiates with infrared light.
The biggest bead lighting up the left side of the mask is also the
densest. In fact, some of its central stars might have merged to form a
black hole. (Now, that would be quite the Mardi Gras mask!)
This picture, taken by Spitzer's infrared array camera, is a four-channel
composite. It shows light with wavelengths of 3.6 microns (blue); 4.5
microns (green); and 5.8 and 8.0 microns (red). The contribution from
starlight (measured at 3.6 microns) has been subtracted from the 5.8- and
8-micron channels to enhance the visibility of the dust features.
