Astronomers Detect Methylidynium in Distant Star-Forming Galaxies | Astronomy

For the first time, astronomers have detected the presence of CH+ — an ion of the CH molecule known as methylidynium to chemists — in distant starburst galaxies.

This image shows how gas falling into distant starburst galaxies ends up in vast turbulent reservoirs of cool gas extending 30,000 light-years from the central regions. Image credit: L. Benassi / ESO.

Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers detected CH+ emission and absorption lines in the spectra of six lensed starburst galaxies at redshifts 2.1 to 2.5, including the Eyelash galaxy (also known as SMM J2135-0102).

“CH+ is a special molecule,” said Dr. Martin Zwaan, an astronomer at ESO.

“It needs a lot of energy to form and is very reactive, which means its lifetime is very short and it can’t be transported far. CH+ therefore traces how energy flows in the galaxies and their surroundings.”

How CH+ traces energy can be thought of by analogy to being on a boat in a tropical ocean on a dark, moonless night. When the conditions are right, fluorescent plankton can light up around the boat as it sails.

The turbulence caused by the boat sliding through the water excites the plankton to emit light, which reveals the existence of the turbulent regions in the underlying dark water.

Since CH+ forms exclusively in small areas where turbulent motions of gas dissipate, its detection in essence traces energy on a galactic scale.

This ALMA image shows the Eyelash galaxy, a remote starburst galaxy that appears double and brightened by gravitational lensing. ALMA has been used to detect turbulent reservoirs of cold gas surrounding this and other distant starburst galaxies. By detecting CH+ for the first time in the distant Universe, this research opens up a new window of exploration into a critical epoch of star formation. Image credit: ALMA / ESO / NAOJ / NRAO / E. Falgarone et al.

The observed CH+ reveals dense shock waves, powered by hot,…

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