Hidden in Plain Sight: faint galaxy discovered in our local universe

What is the News?

Indian astronomers have discovered a Faint Galaxy named UVIT J2022 that remained hidden until now. 

What are Faint Galaxies?

Faint Galaxies are called low surface brightness galaxies or ultra-diffuse galaxies and have a surface brightness that is at least ten times fainter than the surrounding night sky. 

Such faint galaxies may account for up to 15 % of the mass of the universe. However, they are difficult to detect because of their inherent low luminosities.

What is UVIT J2022?

It is a faint galaxy. It was discovered while studying a known galaxy, NGC6902A. This faint galaxy is in the Milky Way’s neighbourhood situated 136 million light-years away.

It remained undetected because it lay in front of a much brighter galaxy that is further away. Moreover, it is extremely faint – about ten times fainter than the surrounding night sky.

What is the significance of this study?

Firstly, this study raises the possibility that there could be similar diffuse galaxies that have been wrongly interpreted as interacting galaxies due to their superposition with foreground or background galaxies.

Secondly, the material that the humans see around is known as baryonic matter. Studies suggest that baryonic matter makes up 5% of the Universe’s mass. The rest of the mass should be contributed by unknown forms such as dark matter and dark energy.

— However, humans still do not have a clear understanding about the 5% of the baryonic content present in the Universe. These faint galaxies can act as a link for understanding the origin of missing baryons in the universe, as they may contribute significantly to the baryonic mass in the universe.

Source: This post is based on the article “Hidden in Plain Sight: faint galaxy discovered in our local universe” published in PIB on 1st April 2022.