PUNE: An international team of researchers has found evidence for a compact radio jet inducing turbulence and increasing gas temperature as it progresses through the interstellar medium of the Teacup galaxy. The study was led by Dr Anelise Audibert and Dr Cristina Ramos Almeida of the Instituto de Astrofísica de Canarias (IAC), Canary Islands, Spain, and involved co-authors Meenakshi and professor Dipanjan Mukherjee from the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, who, using results from their hydrodynamical simulations, provided the theoretical interpretation of the astronomical observations carried out using the Atacama Large millimetre or submillimetre Array (ALMA) telescope in Chile. The findings were published in the journal Astronomy & Astrophysics Letters (link) on Tuesday.
The IAC-led team discovered a perfect case to study the interaction of the radio jet with the cold gas around a massive quasar, named the Teacup galaxy. The Teacup is a radio-quiet quasar located 1.3 billion light years from the Earth and its nickname comes from the expanding bubbles seen in optical and radio images, which resembles the handle of a teacup. In addition, the central kiloparsec (around 3,300 light years) hosts a compact and young radio jet that has a small inclination relative to the galaxy disk.
The work led by Audibert was able to capture the emission from the dense and cold gas in the Teacup, traced by two carbon monoxide molecules. “Based on these observations, we find that the compact jet is clearly perturbing the gas distribution, clearing out the gas from the centre and pushing it away, despite the fact that it is a low-power jet,” said Audibert.
“Not only does the jet stir the gas in the Teacup, but also the motion of the cold gas is found to be accelerated by the jet in an unusual way. We expected to detect extreme conditions in the regions along the jet’s impact. However, when we looked at the observations, we found that the cold gas is turbulent and warmer in the directions perpendicular to the jet’s propagation. Although such phenomena have been detected in a handful of systems for hotter ionised gas, this is one of the first detections for a similar effect in cold, denser gas. This is caused by shocks from a bubble produced by the jet that heats up and blows the gas in its lateral expansion away from the jet,” said Mukherjee.
{{/usCountry}}“Not only does the jet stir the gas in the Teacup, but also the motion of the cold gas is found to be accelerated by the jet in an unusual way. We expected to detect extreme conditions in the regions along the jet’s impact. However, when we looked at the observations, we found that the cold gas is turbulent and warmer in the directions perpendicular to the jet’s propagation. Although such phenomena have been detected in a handful of systems for hotter ionised gas, this is one of the first detections for a similar effect in cold, denser gas. This is caused by shocks from a bubble produced by the jet that heats up and blows the gas in its lateral expansion away from the jet,” said Mukherjee.
{{/usCountry}}The findings were supported by comparing with high-resolution hydrodynamic simulations. The results from the simulations, when analysed by Meenakshi, showed an excellent match with the observations, thus confirming the theoretical models.
Co-author of the study, Almeida, said, “Low-power jets were once believed to have a negligible impact in the galaxy but our results show that even in the case of radio-quiet galaxies, the jet is redistributing mass, metals, and preventing further star formation.”