Image: NASA, William C. Keel (University of Alabama, Tuscaloosa)
Two galaxies in the constellation Taurus have locked horns: NGC 1409 and NGC 1410, bound by gravity, are spinning around each other at 670,000 miles an hour. And as this image taken by the Hubble Space Telescope reveals, a continuous intergalactic pipeline passes between them. Indeed, astronomers have found that a fine stream of gas and dust--appearing here as a dark thread--funnels from NGC 1410 (left) to NGC 1409 (right), traveling across more than 20,000 light-years of space. Although many images show colliding galaxies, this one offers possibly the clearest demonstration yet of how some galaxies dump material onto their companions. William Keel of the University of Alabama and his colleagues presented the finding yesterday at the 197th meeting of the American Astronomical Society in San Diego.
The researchers are not certain why the pipeline flows one way towards NGC 1409, nor why the incoming material has not fueled the birth of more stars there. They speculate that the gas entering NGC 1409 is too hot, and that the pipeline has not provided the galaxy with enough star-making material. In fact, the pipeline is only 500 light-years wide, and moves only 0.02 solar masses of matter a year. Of interest, the interaction between the two galaxies does appear to have kindled rapid star births in NGC 1410. This activity is plainly seen by the blue color in its arms. Astronomers expect that the two galaxies will continue to dance, bumping together and pulling apart, until they finally merge some 200 million years from now.