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Spitzer's coiled creature
of the night


Posted: July 24, 2009

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NASA’s Spitzer Space Telescope has captured a twisted galactic monster with an eye-shaped object glaring from its core.

NGC 1097 is a spiral galaxy, its spindly arms wrapped around its deadly “eye”, or black hole, and its presence betrayed by a bright ring of stars. Some of these stars will meet their fate in the jaws of the black hole, which weighs in at 100 million times the mass of our Sun, along with surrounding gas and dust that is also swept up by the monster’s dominating gravitational pull.

NGC 1097 is located 50 million light-years away. In this colour-coded image, infrared light with shorter wavelengths is blue, while longer-wavelength light is red. Image: NASA/JPL-Caltech/The SINGS Team (SSC/Caltech).

"The fate of this black hole and others like it is an active area of research," says George Helou, deputy director of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "Some theories hold that the black hole might quiet down and eventually enter a more dormant state like our Milky Way black hole." Our Milky Way's central black hole is tame by comparison, with a mass of just a few million suns.

The ring surrounding the black hole is also a focus of interest for astronomers studying this system. Glowing with newborn stars, this stellar factory is fuelled by the inflow of material toward the central bar of the galaxy. "The ring itself is a fascinating object worthy of study because it is forming stars at a very high rate," says Kartik Sheth, an astronomer at NASA's Spitzer Science Center.

Newborn stars light up the dust in the galaxy’s red spiral arms, while older blue members of the population punctuate the space in between. A fuzzy blue companion galaxy snuggles into the arms of NGC 1097 to the left in the new image. "The companion galaxy that looks as if it's playing peek-a-boo through the larger galaxy could have plunged through, poking a hole," says Helou. "But we don't know this for sure. It could also just happen to be aligned with a gap in the arms."

This image was taken during Spitzer's so-called cold mission, which lasted more than five and a half years. Since the telescope ran out of the coolant needed to chill some of its infrared instruments in mid-May this year, Spitzer will soon being its warm mission phase at a temperature of 30 Kelvin, with many more exciting discoveries expected in the near future.