Here we show recent research results from the Radio Astronomy/Very-Long-Baseline Interferometry department.
How high-energy particles shape the appearance of M87: a new study
20 April 2022
An international team of astronomers led by Christian M. Fromm, affiliated to the MPI für Radioastronomie, as well as to the Universities of Würzburg and Frankfurt, presents a new study in the present issue of Astronomy & Astrophysics. Based on the previous work from the Event Horizon Telescope, which captured images of the innermost emission of the M87 galaxy, revealing a ring-like structure surrounding a supermassive black hole. However, at lower frequencies, the galaxy had a large-scale jet emitting non-thermal energy. To better understand these observations, the team led by Dr. Fromm used simulations to model the accretion of magnetized plasma onto black holes and jet launching. They were able to model the observed broad-band spectrum of M87 and fit the structure of the jet using simulations that included a mixture of thermal and non-thermal particle distributions. These results provide new insights into the behavior of black holes and the surrounding material.
More information is available at the original publication here.
The collimation in the twin jet of NGC 1052
09 February 2022
The radio galaxy NGC 1052 has been explored in the innermost regions of its dual jet by means of radio interferometr. An international team of radio astronomers led by Dr. Anne-Kathrin Baczko from our institut shows that the jet presents a clear transition in the collimation profile at 10 000 gravitational radii, with an upstream parabolic shape, which turns into conical downstream. At about 1 000 gravitational radii, the jet has an opening angle of about 30°. These results show that the approaching (eastern) and receding (western) show a somewhat different emission, for which the receding jet emission my be affected by an absorption cloud of gas in the line of sight. More information is available at the original publication in the journal Astronomy & Astrophysics, available here.
Blazar 0716+714 flaring from the radio through the gamma-ray sky
26 January 2022
An international team of astronomers led by DaeWon Kim from the MPI für Radioastronomie have studied blazar 0716+714, more specifically its jet. They used radio waves and gamma rays to create a picture of how the jet behaves. Over a period of ten years, they found that there were times when the radio and gamma rays were closely linked, and other times when they were not. They discovered that the gamma rays were being produced by multiple regions in the jet, upstream from where the radio waves were being produced. They were also able to identify different parts of the jet moving at different speeds, and they found that the brightness of the jet decreased as it got further from the center. Interestingly, the researchers noticed that the times when the radio and gamma rays were closely linked coincided with times when the jet was pointing in a specific direction. They suggest that a moving disturbance, like a shockwave, passing through the radio core and the direction of the jet could be causing the correlation between the radio and gamma rays. Overall, this study helps us understand how these distant objects behave and provides insight into the complex processes that create the emissions we observe.
More details on the work are presented in the present issue of The Astrophysical Journal, here.