A team of researchers have revealed an incredible photo of the molecular zone of our galaxy, the Milky Way, an area with incredibly low levels of star formation compared to other galaxies.
Compared to other galaxies in our universe, the Milky Way is a fairly subtle character. There are in the cosmos far more luminous galaxies, because of the presence of gas in their Central Molecular Zones (CMZ). The CMZ is heated by massive explosions during the formation of the stars that surround the supermassive black hole at the core of a galaxy. The heart of the Milky Way also has a supermassive black hole, and all the gas needed to form new stars. But for some strange reason, the formation of stars in our galaxy is below average.
In addressing the question of why, an international team of astronomers, led by Daniel Walker of the National Astronomical Observatory of Japan, turned their attentions to the “heart” of our galaxy. The researchers analysed a sample of thirteen high-mass cores which are potentially young stars in the initial stage of development. These cores have masses ranging between 50 and 2,150 solar masses, and radii of 0.1 to 0.25 parsecs (between 0.326 and 0.815 light years). After having compared these cores with high mass cores in the galactic disc (the plane in which the spirals, bars and discs of disc galaxies exist), they discovered that they were fairly similar in mass and in size, despite being subjected to varying external pressure.
In order to determine that the external pressure in the Central Molecular Zone was higher, the team observed the spectral lines on formaldehyde and methyl cyanide molecules in order to measure the temperature and kinetics of the gas. The information they gathered indicated that the gaseous environment was highly turbulent, leading them to the conclusion that the agitated environment in this area is responsible for inhibiting star formation.
All in all, the levels of star formation in the Central Molecular Zone (the central area of our galaxy) depends not only on the quantity of gas and dust, but also on the nature of the gas environment itself. These results could inform future research, not only regarding the Milky Way, but also other galaxies -especially in terms of the relationship between supermassive black holes, star formation and the evolution of galaxies.
This study also allows us to show you this incredible photo taken by Spitzer, NASA’s spatial telescope: an infrared image of the centre of the Milky Way, where the supermassive black hole of our galaxy (Saggitarius) is found.