Powerful Galactic Winds Empty Out Galaxy Cores And Regulate Star Formation

Ionized and molecular gases driven out from the centre of a galaxy during the active phase of a black hole's formation can affect star formation in a major way, a study has found.

When a black hole is growing swiftly by consuming material in its galaxy, the galaxy will have what is known as an Active Galactic Nucleus, or AGN. One of the AGN's effect is the galactic winds, which play a role in star formation.

A team of astronomers used an EMIR infrared spectrograph and developed at the Instituto de Astrofisica de Canarias (IAC) to study the coolest and most distant objects in the universe by analyzing infrared light. The device was installed in June 2016 after an exhaustive test phase in the workshops of the instrument division of the IAC headquarters in La Laguna.

The astronomers found that ionized winds reach velocities of up to 1,200 km/s. But it is the molecular wind that is emptying the gas reservoirs of the galaxy, up to 176 solar masses per year, and probably impeding star formation. Co-author of the study and researcher at IAC, Jose Pulido, said new observations with ALMA will let them confirm the estimate.

IAC researcher Cristina Ramos Almeida said the EMIR allowed the research team to use the infrared range to study the winds of ionized and molecular gas from the quasar J1509+0434. “This analysis is very important because they don’t always show similar properties, which tells us a great deal about how these winds are produced and how they affect their host galaxies,” she said.

Almeida explained that the study of other quasars will allow the team to understand what was happening in galaxies when they were younger and when they were forming their structures.

In 2018, the Nature Magazine published an article about the discovery of a galaxy that lacked dark matter. The findings of the researchers at IAC seems to have solved this mystery. Galaxies with no dark matter are impossible to understand in the framework in the current theory of galaxy formation. Dark matter is fundamental in causing the collapse of the gas to form stars.