International group of scientists study quasar jets in ground breaking research

An international team of scientists has published observations about the deepest part of a quasar's plasma jet, discovering the inner workings of how the jets collimate.

According to a release by MIT News on November 22, the quasar is called 3C 273 and is located in the constellation Virgo. Quasars are also known as quasi-stellar objects and this one was the first ever discovered. They are the brightest and most active of the supermassive black holes. The discovery is the first of its kind and should lead to additional research and findings about these black holes.

“3C 273 has been studied for decades as the ideal closest laboratory for quasar jets,” Hiroki Okino, lead author of this paper and a PhD student at the University of Tokyo and National Astronomical Observatory of Japan, said in the MIT News report. “However, even though the quasar is a close neighbor, until recently, we didn’t have an eye sharp enough to see where this narrow powerful flow of plasma is shaped.”

The study was published in The Astrophysical Journal and discusses being able to see deepest into the black hole where a plasma flow is emitted that moves at about the speed of light. This stems from data gathered in 2017. While the jets have been studied for decades, there is still much for scientists to discover. One aspect that was unknown was how and where the jets collimated. This research involves setting up radio antennas around the world with the Global Millimeter Very Long Baseline Interferometry (VLBI) Array and the Atacama Large Millimeter/sub-millimeter Array (ALMA) located in Chili. Observations were also made with the High Sensitivity Array.

The new image of the jet is the first time scientists have been able to see where this collimation happens.

“It is striking to see that the shape of the powerful stream is slowly formed over a long distance in an extremely active quasar. This has also been discovered nearby in much fainter and less active supermassive black holes,” Kazunori Akiyama, research scientist at MIT Haystack Observatory and project lead, said in the MIT News report. “The results pose a new question: How does the jet collimation happen so consistently across such varied black hole systems?”

Lynn Matthews, MIT Haystack Observatory principal research scientist and commissioning scientist for the APP, added, “The ability to use ALMA as part of global VLBI networks has been a complete game-changer for black hole science. It enabled us to obtain the first-ever images of supermassive black holes, and now it is helping us to see for the first time incredible new details about how black holes power their jets.”

The research is leading to additional study of the jet collimation processes in other types of black holes. The data obtained at higher frequencies, such as 230 and 345 GHz with the Event Horizon Telescope (EHT), will be beneficial for scientists to further their discoveries.

According to Keiichi Asada, associate research fellow at the Academia Sinica, Institute of Astronomy and Astrophysics (ASIAA) in Taiwan, “This discovery sheds new light on jet collimation in the quasar jets. The sharper eyes of the EHT will enable access to similar regions in more distant quasar jets. We hope to be able to make progress on our new ‘homework’ from this study, which may allow us to finally answer the hundred-year-old problem of how jets are collimated.”