Max Planck Institute for Radio Astronomy

Blazar Jet Variability probes precession caused by orbiting black holes in the centers of galaxies

New observations reveal how a powerful jet forms around a black hole

Large-scale observational campaign provides new insights into an assumed black hole binary at the centre of the active galaxy OJ 287

First detection of the heavy ¹⁸O isotope both in the upper and lower atmosphere of Earth

International team observes innermost structure of quasar 3C 273

The active nuclei of galaxies are among the mightiest powerhouses in the cosmos. They derive their energy from black holes at their centers, which sometimes occur in pairs. In a large-scale campaign, a group led by Stefanie Komossa from the Max Planck Institute for Radio Astronomy in Bonn used several telescopes to peer into the heart of one such energy slingshot.

Sitting deep in the heart of the Milky Way, it is 27,000 light years from Earth and resembles a donut: this is how the black hole at the center of our galaxy looks in the image obtained by researchers using the Event Horizon Telescope (EHT).

Centaurus is one of the most famous constellations in the southern sky. Take a closer look at the constellation through binoculars and you’ll see a pale nebula known as Centaurus A – it is in fact a distant galaxy in which a supermassive black hole resides. Michael Janssen from the Max Planck Institute for Radio Astronomy in Bonn and Radboud University Nijmegen led an Event Horizon Telescope team that has now come closer than ever before to understanding the nature of this gravity trap.

A cosmic lightning storm is playing out all around us. At any given moment, somewhere in the sky, a burst of radiation flashes and then fades away. Only observable with radio telescopes, these bursts last one-thousandth of a second and are one of astrophysics’ greatest mysteries. Scientists rather doubt this is evidence of warlike aliens fighting “star wars” in the vastness of space. Experts have named them “fast radio bursts” – but where do they come from?

Black holes swallow all light, making them invisible. That’s what you’d think anyway, but astronomers thankfully know that this isn’t quite the case. They are, in fact, surrounded by a glowing disc of gas, which makes them visible against this bright background, like a black cat on a white sofa. And that’s how the Event Horizon Telescope has now succeeded in taking the first picture of a black hole. Researchers from the Max Planck Institute for Radio Astronomy in Bonn and the Institute for Radio Astronomy in the Millimeter Range (IRAM) in Grenoble, France, were among those making the observations.

This year, we were able to present the first image of the "shadow" of the black hole at the center of our own galaxy, the Milky Way. It is the result of years of data analysis, which began in 2017 with the Event Horizon Telescope and resulted in the first image of such a black hole in the galaxy Messier 87 in 2019. Once again, over 30 employees from all departments of the institute were involved. This image is also a scientific breakthrough. But what makes it special? Why was the data analysis much more challenging than in the case of M87?

2021 marked the fiftieth anniversary of the inauguration of the radio telescope in Effelsberg. In the past decades, the telescope, whose construction broke new technical ground, has produced numerous important observational results. Thanks to constant improvements and renewals it is still state-of-the-art. Selected current observational projects are presented here.

Extremely precise measurements of the motion of a fast-spinning pulsar in a triple star system provide one of the strongest tests ever of a simple, but fundamental prediction of general relativity: that gravity affects all objects with the same acceleration, without regard for their composition, density or the strength of their own gravitational field. General relativity has again survived this test, one of the most stringent ever, which strongly constrains many alternative theories of gravity.

On April 10, 2019, the first image of a black hole was published by a team of 347 international scientists from 59 institutes in 18 countries. Theoretical work and indirect evidence for the existence of black holes has been around for a long time. Only now did the observations provide the necessary resolution for an image made possible by a combination of seven radio telescopes scattered across the Earth, observing the centre of the galaxy M87. More than 30 scientists and engineers of the Max Planck Institute for Radio Astronomy in Bonn are involved in this success.

The airborne observatory SOFIA allows astronomical observations in the Far-Infrared, which is not accessible from the ground.  It covers the most important cooling lines of the interstellar medium. Velocity-resolved observations of these lines are crucial for our understanding of the star formation process. Here we present observations of the ionized carbon finestructure line in the Lagoon Nebula, which for the first time reveals the gas motions in the immediate environment of the nebula.