The mystery of the Hanny object

2011/01/13 Kortabitarte Egiguren, Irati - Elhuyar Zientzia

• Astronomia

A bright green gas cloud appears in the image above the Hubble telescope. Hanny is an object. This object has aroused the curiosity of astronomers since its discovery in 2007. Why is this gas cloud so clear? Why is it green? The images of the Hubble telescope have revealed this.

The nearby galaxy IC 2497 illuminates the Hanny object. This galaxy, like many other galaxies, has a black hole in the nucleus. The matter ingested by this black hole (gases and stars) emits jets of hot gas and high energy radiation. This radiation when colliding with the gas cloud excites the oxygen atoms, which is the ionized oxygen that causes the green color of the brightness. Such galaxies are also known as quasars.

In the upper right of the object appears a group of young stars (in yellow). These young stars indicate that particle jets launched by the quasar have collided with the gas cloud. This collision produces the compression of gas and the birth of new stars.

Image courtesy of: ANDÉN, ESA, W. Keel (University of Alabama) and the Galaxy Zoo Team group.