To investigate the impact of radio jets on the interstellar medium (ISM) of galaxies with active galactic nuclei (AGN), an international scientific team led by researcher Anelise Audibert from the Instituto de Astrofísica de Canarias (IAC) discovered an ideal case: the teacup universe. They studied the radiojet’s interaction with the cold gas surrounding a huge quasar.
The Teacup is a radioquiet quasar 1.3 billion light-years away, so named because one of the expanding bubbles visible in optical and radio images resembles the handle of a teacup. In addition, the core region of the galaxy, which spans about 3,300 light-years, contains a compact, juvenile radiojet with a slight inclination toward the galactic disk.
To characterize the cold, dense gas in the central part of the teacup, the team used observations from the Atacama Large Millimeter/submillimeter Array (ALMA). They specifically identified emissions of carbon monoxide molecules that can only exist under certain conditions of density and temperature.
The observations also showed that despite its low power, the compact jet disrupts the distribution of the gas and heats it up, accelerating it unusually.
When the team looked at the results, they found that the cold gas was more turbulent and warmer in the directions perpendicular to the jet propagation, contrary to what they expected to be seen in the affected areas along the jet.
The IAC researcher Anelise Audibert said: “This is caused by the shocks caused by the jet-driven bubble, which heats up and blows the gas into its lateral expansion. Supported by the comparison with computer simulations, we believe that the orientation between the cold gas disk and the jet is a crucial factor in efficiently driving these crosswinds.”
Cristina Ramos Almeida, an IAC researcher and co-author of the study, said: “Low-powered jets used to be believed to have a negligible impact on the galaxy, but works like ours show that, even in the case of radioquiet galaxies, jets can redistribute and disrupt the surrounding gas, and this will have an impact on the galaxy’s ability to form new stars.”
- A. Audibert et al., Jet-induced molecular gas excitation and turbulence in the Teacup, Astronomy & Astrophysics (2023). DOI: 10.1051/0004-6361/202345964