27.04.2016 change 27.04.2016

Polish astronomers discovered alternating emissions of water and methanol in space

All research team members (from left): Dr. Anna Bartkiewicz, Mateusz Olech, Prof. Marian Szymczak, Dr. Paweł Wolak, Dr. Marcin Gawroński - all from Torun Centre for Astronomy of the Nicolas Copernicus University. Photo by Krzysztof Bartkiewicz (Torun Centre for Astronomy). All research team members (from left): Dr. Anna Bartkiewicz, Mateusz Olech, Prof. Marian Szymczak, Dr. Paweł Wolak, Dr. Marcin Gawroński - all from Torun Centre for Astronomy of the Nicolas Copernicus University. Photo by Krzysztof Bartkiewicz (Torun Centre for Astronomy).

A team of astronomers from Torun Centre for Astronomy of the Nicolas Copernicus University observed the hitherto unknown phenomenon of alternating emission of radio waves from molecules of methanol and water vapour around a young star. This is the only known object in the universe with such properties. Observations were carried out with the biggest Polish radio telescope operating near Toruń.

The research group led by Prof. Marian Szymczak from Torun Centre for Astronomy of the Nicolaus Copernicus University conducted observations of radio source designated G107.298+5.639, G107 in short. For the first time they could observe in space an alternating, linked maser emission of two types of masers, methanol and water. The two types of masers are often found together, but so far no theory proposed a relationship between their magnitudes.

Masers are emissions of radio waves, which are formed on a principle similar to the emission of light in lasers. In the clouds surrounding the emerging massive stars there are many different molecules, including the simplest alcohol: methanol, and water (in a gaseous stare). Both types of masers are driven by different processes. Methanol masers are affected by infrared dust and, in the case of water masers these are shock waves. Masers have their characteristic frequencies, emission of methanol molecules occurs at 6.7 GHz, and water molecules at 22 GHz, resulting respectively in 4.5 cm and 1.3 cm wavelengths.

Methanol and water masers occur in the formation areas of massive stars. Irradiance of masers is strongly dependent on the physical conditions prevailing in the environment, so based on their observations conclusions may be drawn about the processes taking place in areas around emerging stars.

"Maser emissions from space have been known for decades. Currently, about 1,000 of methanol masers are catalogued, of which 284 are monitored by our radio telescope. Of particular interest to radioastronomers are objects in which the variability of methanol masers is cyclical. Currently we know only 16 such periodic methanol masers, of which five were discovered by our team during observations with Torun radio telescope. One of the objects we study, called G107, turned out to be very special - you can figuratively say that it shows us a cosmic hide and seek" - explained Prof. Marian Szymczak in an interview with PAP.

Mateusz Olech, Prof. Szymczak\'s PhD student, focuses on variable masers. He said that the object G107 was known when Torun radio telescope observations began in August 2014. It was known that there was a periodic methanol maser, but there was no information about the cyclical variability in the case of the water maser. Dr. Paweł Wolak, who also took part in the research project, was not discouraged by the fact that in previous observations of the object, the source G107 did not show anything special in the emission of maser water and decided to carry out observations with the newly built receiver on the 32-meter radio telescope RT4 at the NCU\'s Centre for Astronomy.

After several days of observation it turned out that the object\'s emission shows periodicity, and in addition there is a never-before-observed phenomenon. Flares of methanol maser alternated with flares of water vapour maser. The maps obtained through radio interferometry showed that clouds of methanol and water are fairly close to each other in space.

"It looks as if the two phenomenon avoided coexistence at the same time. Methanol maser in G107 glows for several days, and then disappears for more than 20 days, while the water vapour maser appears. Then maser at 22 GHz disappears and the flare at 6.7 GHz reappears" explained Prof. Szymczak.

Polish astronomers have found a unique cosmic laboratory, the studies which will allow to verify theories that describe the processes associated with masers and areas of massive star formation.

The members of the research team were: Prof. Marian Szymczak, Mateusz Olech, Dr. Paweł Wolak, Dr. Anna Bartkiewicz, Dr. Marcin Gawronski (all from NCU\'s Centre for Astronomy). Article outlining the research results has been published in the "Monthly Notices of the Royal Astronomical Society Letters".

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