NASA’s Hubble spots giant gas halo encircling Andromeda Galaxy a million light-years away

Scientists have just discovered a massive halo of gas that has been encompassing the Andromeda galaxy which is the nearest major galaxy to our own Milky Way.

They have employed NASA’s Hubble Space Telescope for spotting this ring that extends out to about a million light-years away from Andromeda, which is about half the distance to the Milky Way.

In what is known as the Local Group, a collection of galaxies which includes the Milky Way along with 45 other galaxies, the Andromeda galaxy is the largest of them all. The Andromeda has about a trillion stars and is about 25% brighter than the Milky Way.

This discovery of a gas halo could assist astronomers in understanding the structure and formation of giant spiral galaxies and both Andromeda and the Milky Way are considered to be spiral galaxies.

This study has been published in the Astrophysical Journal and it has found that the halo has 100 times the diameter of the moon. The gas is invisible therefore scientists had to take help from quasars for making their observations. Quasars are distant star-like objects which shine very brightly because of gas falling into supermassive black hole.

The lead author of the study and an astrophysicist at the University of Notre Dame Ind. has said that, “Halos are the gaseous atmospheres of galaxies. The properties of these gaseous halos control the rate at which stars form in galaxies according to models of galaxy formation according to Tech Times

Co-investigator J. Christopher Howk, also of Notre Dame, said, “As the light from the quasars travels toward Hubble, the halo’s gas will absorb some of that light and make the quasar appear a little darker in just a very small wavelength range. By measuring the dip in brightness in that range, we can tell how much halo gas from M31 (Andromeda) there is between us and that quasar.”

The researchers have used five years of Hubble data as part of their research and have looked at the ultraviolet light to acquire details on the extent and nature of galaxy gas halos. The researchers says that if the Milky Way has a similar halo, the two halos could one day merge before the galaxies collide, making a giant elliptical galaxy in about another 4 billion years.