Distant Spiral Galaxy May Reveal Clues About Our Milky Way

/ Source: Space.com

A beautiful spiral galaxy 60 million light-years from Earth could help astronomers better understand our own Milky Way because of a trademark central bar-like structure.

The galaxy, NGC 1365, is one of the most-studied barred spiral galaxies. It is sometimes called the Great Barred Spiral Galaxy because of its strikingly perfect form.

Now, a new photo released by the European Southern Observatory today (Sept. 22) shows the galaxy in exacting detail, and may help astronomers who are trying to determine if our own Milky Way contains a central bar. [ New photo of the Great Barred Spiral Galaxy.]

Barred galaxies like NGC 1365 are actually quite common, scientists said. According to recent estimates, two thirds of spiral galaxies are barred, and recent observations have contributed evidence of a bar in the Milky Way.

Astronomers have used NGC 1365 to study how spiral galaxies form and evolve. By examining the complex flow of material within the galaxy, researchers can pinpoint how these processes affect the reservoirs of gas from which new stars can form.

Galaxy bar exam

The galaxy NGC 1365 has a straight bar packed with stars at its center, with two visible outer spiral arms. The entire galaxy is laced with delicate dust lanes, and close to the center is also a second spiral structure.

The new image of the galaxy was taken with the powerful HAWK-I camera on ESO's Very Large Telescope at the Paranal Observatory in Chile. It was captured in infrared light, which cuts through the dust that obscures parts of the galaxy when viewed in visible light.

The photo reveals a clear glow from the vast number of stars that are located in both the bar and spiral arms.

NGC 1365 is located within the constellation of Fornax (the Furnace). The entire galaxy, including its two huge outer spiral arms, spans approximately 200,000 light-years wide. One light year is the distance light travels in one year, or about 6 trillion miles (9.7 trillion km).

A bar in space

The huge bar structure within NGC 1365 disturbs the shape of the galaxy's gravitational field, which causes regions of gas to compress and trigger star formation. Many huge young star clusters trace out the main spiral arms and each contains anywhere from hundreds to thousands of bright young stars that are less than 10 million years old.

In the photo, most of the tiny clumps that are visible are actually star clusters, but the galaxy is too remote for single tars to be seen individually.

The galaxy's bar consists primarily of older stars long past their prime, but many new stars are born in the stellar nurseries of gas and dust in the inner spiral close to the nucleus.

The bar also funnels gas and dust gravitationally to the very center of the galaxy, where astronomers have found evidence to support the presence of a supermassive black hole, well hidden among myriads of intensely bright new stars.