Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have detected over 100 molecular species in the center of the starburst galaxy NGC 253 — far more than previously observed in galaxies beyond the Milky Way.
In the Universe, some galaxies form stars much faster than our Milky Way Galaxy. These galaxies are called starburst galaxies.
It is still a mystery how exactly such a highly prolific formation of stars can occur and how it ends.
The chance for stars to form depends on the properties of the raw material from which stars are born, such as molecular gas, a gaseous material of various molecules.
For example, stars form in dense regions within molecular clouds where gravity can act more effectively.
Sometime after the active formation of stars, existing stars and explosions of dead stars impart energy to the surrounding medium, which could hinder future star formation.
These physical processes impact the chemistry of the galaxy and imprint a signature in the strengths of signals from molecules.
Because each molecule emits at specific frequencies, observations over a wide frequency range enable us to analyze the physical properties and give us insights into the mechanism of starbursts.
As part of the ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI), Dr. Nanase Harada of the National Astronomical Observatory of Japan observed NGC 253, a starburst galaxy 11.5 million light-years away in the constellation of Sculptor.
They were able to detect more than one hundred molecular species in the galaxy’s central molecular zone.
This chemical feedstock is the richest found outside the Milky Way, and it includes molecules that have been detected for the first time beyond the Milky Way, such as ethanol and the phosphorus-bearing species PN.
First, the astronomers found that high-density molecular gas will likely promote active star formation in this galaxy.
Each molecule emits at multiple frequencies, and their…
Read the full article here