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Dwarf Galaxies Swimming in Tidal Tails December 1, 2005

Posted by jtintle in Spitzer Space Telescope (SST), Cornell Univ., Deep Space, Infrared Array Camera (IRAC), JPL, NASA, Space Fotos.
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Dwarf Galaxies Swimming in Tidal Tails

Mission: Spitzer Space Telescope (SST)
Spacecraft: Spitzer Space Telescope (SST)
Instrument: Infrared Array Camera (IRAC)
Product Size: 848 samples x 711 lines
Produced By: California Institute of Technology
Full-Res TIFF: PIA03605.tif (1.811 MB)
Full-Res JPEG: PIA03605.jpg (60.3 kB)

This false-color infrared image from NASA’s Spitzer Space Telescope shows little “dwarf galaxies” forming in the “tails” of two larger galaxies that are colliding together. The big galaxies are at the center of the picture, while the dwarfs can be seen as red dots in the red streamers, or tidal tails. The two blue dots above the big galaxies are stars in the foreground.

Galaxy mergers are common occurrences in the universe; for example, our own Milky Way galaxy will eventually smash into the nearby Andromeda galaxy. When two galaxies meet, they tend to rip each other apart, leaving a trail, called a tidal tail, of gas and dust in their wake. It is out of this galactic debris that new dwarf galaxies are born.

The new Spitzer picture demonstrates that these particular dwarfs are actively forming stars. The red color indicates the presence of dust produced in star-forming regions, including organic molecules called polycyclic aromatic hydrocarbons. These carbon-containing molecules are also found on Earth, in car exhaust and on burnt toast, among other places. Here, the molecules are being heated up by the young stars, and, as a result, shine in infrared light.

This image was taken by the infrared array camera on Spitzer. It is a 4-color composite of infrared light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8.0 microns (red). Starlight has been subtracted from the orange and red channels in order to enhance the dust features.
Image Credit: NASA/JPL-Caltech/Cornell Univ.

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