The Whale Galaxy (NGC 4631)

Posted by Michael Bakich
on Thursday, July 21, 2011

Photo by R. Jay GaBany

Space is an ocean populated with stellar-sized inhabitants engulfed by our most profound mysteries. About 25 million light-years from our location, toward the northern constellation of Canes Venatici, the 140,000 light-year-diameter Whale Galaxy (NGC 4631) plies the cosmic sea like a leviathan seen in profile. The visual impression of spouting water from the Whale’s blowhole is actually the close passing of a small companion galaxy. Its gravitational influence compressed vast clouds of gas and dust within the larger galaxy’s central region, thus inciting a riotous burst of hot, new stars. The radiation released from these new suns also created a superbubble of material that now surrounds the galaxy like an ever-expanding shell. Presumably, once the companion pulls further from the Whale, the starburst event will eventually quiet.

Data: 20-inch RC Optical Systems Ritchey-Chrétien reflector at f/8, Apogee Alta U16M CCD camera, LRGB image with exposures of 1065, 120,120, and 120 minutes, respectively

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