Hubble solves puzzle about loner starburst galaxy

November 21st, 2008 - 2:03 pm ICT by ANI  

Washington, Nov 21 (ANI): Astronomers, using NASAs Hubble space telescope, have resolved a long standing puzzle about why a small, nearby, isolated galaxy is pumping out new stars faster than any galaxy in our local neighborhood.

Now, the Hubble has helped astronomers solve the mystery of the loner starburst galaxy, called NGC 1569, by showing that it is one and a half times farther away than astronomers thought.

The extra distance places the galaxy in the middle of a group of about 10 galaxies centered on the spiral galaxy IC 342.

Gravitational interactions among the groups galaxies may be compressing gas in NGC 1569 and igniting the star-birthing frenzy.

Now, the starburst activity seen in NGC 1569 makes sense, because the galaxy is probably interacting with other galaxies in the group, said the studys leader, Alessandra Aloisi of the Space Telescope Science Institute in Baltimore, Maryland, and the European Space Agency.

Those interactions are probably fueling the star birth, Aloisi added.

The farther distance not only means that the galaxy is intrinsically brighter, but also that it is producing stars two times faster than first thought.

The galaxy is forming stars at a rate more than 100 times higher than the Milky Way. This high star-formation rate has been almost continuous for the past 100 million years.

The Hubble study observed both the galaxys cluttered core and its sparsely populated outer fringes.

The sharpness of Hubbles Advanced Camera pinpointed individual red giants, which led to a precise distance to the galaxy.

Astronomers measured the galaxys distance at nearly 11 million light-years away, about 4 million light-years farther than the old distance.

According to Aloisi, by capturing the entire population of the brightest red giant stars, the team was able to calculate a precise distance to NGC 1569 and resolve the puzzle about the galaxys extreme starburst activity.

This is a prime example of the type of massive starbursts that drive the evolution of galaxies in the distant and young universe, said team member Roeland van der Marel of the Space Telescope Science Institute.

Starburst galaxies can only be studied in detail in the nearby universe, where they are much rarer. Hubble observations of our galactic neighborhood, including this study, are helping astronomers put together a complete picture of the galaxies in our local universe, he added. (ANI)

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