Scientists Are Tracking the Aromatic PAH Molecules of the Early Universe

During the post-Big bang period, the space between planet and stars are occupied with a lot of chemical molecules formed as a dust. Polycyclic aromatic hydrocarbon or PAH is one of those chemical molecules.

Polycyclic aromatic hydrocarbon or PAH is an environmentally persistent organic compound. It consists of two or more single or fused aromatic rings with a pair of carbon atoms shared between rings in their molecules.

On Earth, PAH is found in different natural as well as anthropogenic sources.Primarily it can be produced by volcanoes, production of coke, carbon black, coal tar, petroleum, internal combustion engines etc.

According to Astrophysical Journal, it has been concluded that the different galaxies are emitting PAH at different rates. It has major implications for the astronomical studies of distant galaxies. During the exploration, absorption and emission of energy by dust particles can change astronomer’s observation of distant galaxies.

This whole research conducted by the Astronomy, as a part of the ongoing MOSDEF survey organized by the University of California. According to the survey, they observe the content of about 1,500 galaxies when the universe was 1.5 to 4.5 billion years old using Keck telescope in Hawaii.

In addition, the researchers incorporated infrared imaging data from the NASA’s Spitzer Space Telescope and the ESA operated Herschel Space Observatory. Both are exploring the space to trace the PAH emission in mid-infrared bands and the thermal dust emission in far-infrared wavelengths.

During the study, researchers have been discovered that the low-mass with the lower rate of metal contained galaxies are emitting PAH at very low rate. These results indicate that the PAH molecules are likely to be destroyed in the harsh environment of low mass and metal-poor galaxies with intense radiation.

Moreover, researchers also found that PAH radiation is comparably much weaker in young galaxies. It seems that young galaxies are produced the lesser amount of PAH molecules compare to older one.

Scientists emphasize about the study of the properties of PAH molecule through mid-infrared emission bands in the distant universe. It gives fundamental info for the detailed study of the evolution of chemical compounds and dust particles through the cosmic timeline.