Spiral Survey

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March 22, 1999
Web posted at: 4:40 p.m. EST (2140 GMT)

(CNN) -- The Hubble Space Telescope has provided scientists with a "photo essay" of six spiral galaxies, offering fresh views of star birth.

To capture the images, part of a survey of about 100 spiral galaxies, scientists used the telescope's infrared vision to penetrate the dust clouds swirling around the centers of the galaxies.

The pictures showcase different views of spiral galaxies, including a face-on image of an entire galaxy and a close-up of a core.

In the images, red corresponds to glowing hydrogen, the raw material for star birth. The red knots outlining the curving spiral arms in NGC 5653 and NGC 3593, for example, pinpoint rich star-forming regions where the surrounding hydrogen gas is heated by intense ultraviolet radiation from young, massive stars.

In visible light, many of these regions can be hidden from view by the clouds of gas and dust in which they were born, the Space Telescope Science Institute said in a statement.

The glowing hydrogen found inside the cores of these galaxies, as in NGC 6946, may be due to star birth; radiation from active galactic nuclei, which are powered by massive black holes; or a combination of both, astronomers said. Clusters of stars appear as white dots, as in NGC 2903.

The galaxy cores are mostly white because of their dense concentration of stars. The dark material seen in the images is dust.

The galaxies range in distance from Earth from 19 million light-years to 161 million light-years.

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