An international research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has investigated blazars, accreting supermassive black holes in the centers of galaxies. An important member of the team was astrophysicist Michal Zajaček from the Faculty of Science of Masaryk University. Their findings are presented in the Astrophysical Journal.
Blazars show up when one of the emitted jets in the active galactic nucleus is pointing directly towards the Earth. The researchers present evidence that it is in fact the precession of the jet source, either caused by the presence of a second massive black hole close to the primary one or a warped accretion disk around a single black hole, that is responsible for the observed variability in blazars.
For details of the published study, including contacts and other background information, see the Max Planck Institute's press release HERE.
Original Paper in The Astrophysical Journal is available on:
Britzen et al.: “Precession-induced Variability in AGN Jets and OJ 287”, in The Astrophysical Journal, 951, 106. DOI: 0.3847/1538-4357/accbbc
Illustration showing a jet (yellow) precessing due to a supermassive binary black hole at the center of the galaxy. The larger supermassive black hole is shown in black at the center within the accretion disk, that contains both warmer (blue) and cooler (red) gas. The white arrow indicates the spin of the larger black hole. The second black hole is orbiting (orange) around the central supermassive black hole and the orange arrow shows the orientation of its orbital angular momentum. Due to the misalignment, the torque from the secondary drives the precession of the accretion disk as well as the launched jet (green circle and arrows). Radio emission is indicated with white curved lines. A radio telescope points the direction towards the observer on Earth. The two images visualize how the jet swirls around and produces the variations in radio emission. The jet in the image on the right is turning towards the observer and thus appears brighter in the sky – hence stronger radio emission is seen. Credits: Michal Zajaček, SCI MUNI
Further Information (Links):
MPIfR, Radio Astronomy / VLBI Research Department. https://www.mpifr-bonn.mpg.de/research/vlbi
Monitoring Of Jets in Active galactic nuclei with VLBA Experiments (MOJAVE). https://www.cv.nrao.edu/MOJAVE/
Event Horizon Telescope (EHT). https://eventhorizontelescope.org/
International Pulsar Timing Array (IPTA). https://ipta4gw.org/
Honorary doctorates were awarded, by decision of the Scientific Council of Masaryk University, to Professor Thomas Robert Cech, who made a significant contribution to the formation of the field of biological sciences; and Professor Peter Wolfram Michor, who made a significant contribution to the development...
A team of botanists has revealed significant changes in the distribution of species in the Czech flora. Their study, published in the international scientific journal Biological Conservation, analyzed the decline and increase of individual plant species in the Czech Republic since 1960.
