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Hubble Spots a Grand Spiral of Starbursts
The sparkling scene depicted in this NASA/ESA Hubble Space Telescope image is of the spiral galaxy NGC 5248, located 42 million light-years from Earth in the constellation Boötes. It is also known as Caldwell 45 . The Caldwell catalog holds visually interesting celestial objects that are not as commonly observed by amateur astronomers as the more famous Messier objects.
NGC 5248 is one of the so-called ‘grand design’ spirals, with prominent spiral arms that reach from near the core out through the disk. It also has a faint bar structure at its center, between the inner ends of the spiral arms, which is not quite so obvious in this visible-light portrait from Hubble. Features like these which break the rotational symmetry of a galaxy have a huge influence on how matter moves through it, and eventually its evolution through time. They feed gas from a galaxy’s outer reaches to inner star-forming regions, and even to a galaxy’s central black hole where it can kick-start an active galactic nucleus.
These flows of gas have shaped NGC 5248 in a big way; it has many bright ‘starburst regions’ of intense star formation spread across its disk, which a population of young stars dominates. The galaxy even has two very active, ring-shaped starburst regions around its nucleus, filled with young clusters of stars. These ‘nuclear rings’ are remarkable enough, but normally a nuclear ring tends to block gas from getting further into the core of a galaxy. NGC 5248 having a second ring inside the first is a marker of just how forceful its flows of matter and energy are! Because the galaxy is relatively nearby, its highly visible starburst regions make the galaxy a target for professional and amateur astronomers alike.
Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center
, Greenbelt, MD
claire.andreoli@nasa.gov
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