Astronomers have recently observed a previously unknown extreme star formation in "Medusa merger," a luminous collision of two galaxies at more than 100 million light years from Earth.
The observations, conducted by IRAM using the new NOEMA (Northern Extended Millimeter Array) observatory in the French Alps, reveal a giant region (about 500 light years across) of recently formed massive stars at the center of the "Eye of Medusa," the central gas-rich region of the Medusa merger. The stars are still wrapped in their dusty birth clouds and completely hidden from view in visible light.
Other observatories have previously mapped the Medusa merger but none had detected the existence of this region of high-density gas in the "Eye" until now. The new discovery has not only proven its existence, but also has implications for our understanding of the origins of the Universe and will influence future investigative techniques.
Previous exploration of the Medusa merger had involved carbon monoxide (CO) - the most common molecule used in radio observations at millimeter wavelengths.
Observations of this molecule had never before revealed any detail of a potential "Eye" region. The IRAM team, led by Sabine Koenig, tried a new way in, tuning the NOEMA antennas to detect hydrogen cyanide (HCN) and formylium (HCO+) molecules.
The discovery demonstrated that star development can be probed in stages of formation, which are currently not detectable by tracing carbon monoxide. By successfully detecting other molecules, the extreme star formation observed in the "Eye" demonstrates the existence of more complex chemical formulations than previously thought. This discovery means the understanding of the chemical formation of stars can be hugely expanded upon.
Studies on galaxy collisions and their impact on star formation are fundamental to understanding how galaxies have assembled throughout the history of the Universe.