New molecules can form in the winds of supermassive black holes

Computer model shows new molecules can form when gas caught up in these winds cools.
By Laurel Kornfeld | Feb 02, 2018
New molecules can form in the winds or energetic outflows from supermassive black holes at the centers of galaxies, according to a theory put forward in a study published in Monthly Notices of the Royal Astronomical Society.

The existence of black hole winds was confirmed by scientists in 2015 via the Herschel Space Observatory and the Atacama Large Millimeter Array (ALMA) radio telescope in Chile.

Extremely hot and energetic, these winds destroy everything in their paths, including the molecules that generate star formation.

Surprisingly, scientists detected molecules within these winds, a discovery completely unexpected, as molecules are usually found in the cold recesses of space, not in hot black hole winds, which are described as the universe's most energetic forces.

In 2017, they were even more surprised to find new stars moving quickly within the winds in an environment thought to completely suppress star formation.

While initial questions centered on how the molecules could survive such extreme environments, some astronomers theorized the molecules are not survivors but brand new, formed within the winds and capable of adapting to their extreme conditions.

Alexander Richings, Lindheimer post-doctoral fellow at Northwestern University's Center for Interdisciplinary Research and Exploration in Astrophysics (CIERA), created a computer model simulating the chemical processes that occur in interstellar gas accelerated by radiation from black hole winds. The model showed that gas swept up by the winds can form new molecules, such as hydrogen, carbon monoxide, and water.

"When a black hole wind sweeps up gas from its host galaxy, the gas is heated to high temperatures, which destroy any existing molecules," Richings explained.

"By modeling the molecular chemistry in computer simulations of black hole winds, we found that this swept-up gas can subsequently cool and form new molecules."

Molecular gas can generate new stars that might be more capable of adapting to extreme conditions.

Richings theorizes that molecules formed in black hole winds are likely to appear warmer and brighter in infrared wavelengths than existing molecules caught up in the winds, a proposition he plans to test with the James Webb Space Telescope (JWST), when it is launched in 2019.

JWST will be capable of mapping black hole winds in the infrared.

"This is the first time that the molecule formation process has been simulated in full detail, and in our view, it is a very compelling explanation for the observation that molecules are ubiquitous in supermassive black hole winds, which has been one of the major outstanding problems in the field," said study co-author Claude-Andre Faucher-Giguere of Northwestern's Weinberg College of Arts and Sciences.



We are dedicated to maintaining a respectful community that actively engages in lively discussions about news stories and blog posts. Please keep the following in mind when writing your comments.