Radio astronomy images of the 3C 273 jet. The close-up view on the left is the deepest look yet into the plasma jet of the quasar 3C 273. The image in the center shows the extended structure of the jet. The image on the right is a visible light image of the quasar taken by the Hubble Space Telescope. The radio observations were made by the Global Millimeter VLBI Array (GMVA) joined by the Atacama Large Millimeter/submillimeter Array (ALMA) and the High Sensitivity Array (HSA). Credit: Hiroki Okino and Kazunori Akiyama; GMVA+ALMA and HSA images: Okino et al.; HST Image: ESA/Hubble & NASA
A group of scientists used a network of radio telescopes to observe the narrowing of a quasar jet for the first time. The results show that the narrowing of the jet is not related to the activity of the galaxy which launched it.
Every galaxy has a black hole. A phenomenon known as a quasar is created when huge amounts of energy are released by gas falling towards a black hole. Quasars emit jets of material that are close to the light. How and where quasar jets are collimated has been a mystery for a long time.
Hiroki Okino, a graduate student at the University of Tokyo, is the leader of the international team.
Multifrequency images of 3C 273 jets with the HSA at 43, 22, and 15 GHz and the VLBA at 1.7 GHz. Each panel shows the mean top-set image at each frequency restored by the circular Gaussian beam with the beam solid angle of the uniform-weighting beam size in Table 1. The lowest contour levels are 6.5 mJy beam−1 at 43 GHz, 8.2 mJy beam−1 at 22 GHz, 7.1 mJy beam−1 at 15 GHz, and 11.6 mJy beam−1 at 1.7 GHz. The contours for all images are multiplied by a factor of 2. The lowest contour level of each image is estimated from the mean residual image rms of the top-set reconstructions. Credit: The Astrophysical Journal (2022). DOI: 10.3847/1538-4357/ac97e5
The team found that the jet flowing from the quasar narrows down over a very long distance. This narrowing part of the jet continues incredibly far, well beyond the area where the black hole's gravity dominates. The results show that the structure of the jet is similar to jets launched from nearby galaxies with a low luminosity active nucleus. This would indicate that the collimation of the jet is independent of the activity level in the host galaxy, providing an important clue to unraveling the inner workings of jets.
The results were published in The Astrophysical Journal.
The Astrophysical Journal has more information on Hiroki Okino and his team's work. There is a document titled "10847/1538-4357/ac97e5".
