Hubble reveals a galaxy fit to burst

[Ann]

Hubble reveals a galaxy fit to burst

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NGC 3125. Image credit: ESA/Hubble & NASA.
Acknowledgement: Judy Schmidt.

This NASA/ESA Hubble Space Telescope image reveals the vibrant core of the galaxy NGC 3125. Discovered by John Herschel in 1835, NGC 3125 is a great example of a starburst galaxy — a galaxy in which unusually high numbers of new stars are forming, springing to life within intensely hot clouds of gas.

Located approximately 50 million light-years away in the constellation of Antlia (The Air Pump), NGC 3125 is similar to, but unfathomably brighter and more energetic than, one of the Magellanic Clouds. Spanning 15,000 light-years, the galaxy displays massive and violent bursts of star formation, as shown by the hot, young, and blue stars scattered throughout the galaxy’s rose-tinted core. Some of these clumps of stars are notable — one of the most extreme Wolf–Rayet star clusters in the local universe, NGC 3125-A1, resides within NGC 3125.

Despite their appearance, the fuzzy white blobs dotted around the edge of this galaxy are not stars, but globular clusters. Found within a galaxy’s halo, globular clusters are ancient collections of hundreds of thousands of stars. They orbit around galactic centres like satellites — the Milky Way, for example, hosts over 150 of them.

Ann

[Ann]

My software, Guide, quotes the NGC-IC Project from 1993 to call NGC 3125 an elliptical galaxy. However, Principal Galaxies Catalog had color information on NGC 3125 already in 1989, which proved without a doubt that NGC 3125 is not an elliptical galaxy. The B-V index of NGC 3125 is 0.490, which is blue, and the U-B index of the same galaxy is -0.470, which is tremendously ultraviolet! And the galaxy's far infrared magnitude is almost two magnitudes brighter than its B magnitude. Only a starbursting galaxy would have colors like that, and elliptical galaxies are not starforming - certainly not starbursting.

Ann