photon ring Archives

October 8, 2023October 8, 2023 by Brian Koberlein

Here's What it Would Take to See a Black Hole's Photon Ring

The EHT image of M87* compared to its photon ring. Credit: Left: EHT Collaboration, Right: A.E. Broderick et al, 2022

Supermassive black holes are elusive creatures. Massive gravitational beasts that can power immensely bright quasars, or can lurk quietly among the bright stars of a galactic core. We mostly study them indirectly through their bright accretion disks or powerful jets of plasma they create, but we have been able to observe them more directly, such as our images of M87* and Sag A*. But what still eludes us is capturing a direct image of the enigmatic photon ring. A new work in Acta Astronautica proposes how this might be done.

August 19, 2022August 19, 2022 by Brian Koberlein

Astronomers Have Revealed a Black Hole's Photon Ring for the First Time

The calculated photon ring of M87*. Credit: Broderick, et al

In 2019 the Event Horizon Telescope gave us our first direct image of a black hole. It was a powerful image, but not one with much detail. It looks like a blurry orange donut. To be fair, the real meat of the discovery was in the data, not the image. And as a recent study shows, there’s a great deal more in the data than what we’ve seen.

June 4, 2021June 4, 2021 by Brian Koberlein

What Comes After Photographing a Black Hole's Event Horizon? Could we see the Photon Ring?

Simulation of the photon ring for M87*. Credit: Andrew Chael, et al

In 2019 the Event Horizon Telescope (EHT) gave us the first direct image of a black hole. On one hand, the image it produced was rather unimpressive. Just a circular blur of light surrounding a dark central region. On the other hand, subtle characteristics of the image hold tremendous information about the size and rotation of the black hole. Most of the details of the black hole image are blurred by the limits of the EHT. But the next generation EHT should provide a sharper view, and could reveal the dark edge of a black hole’s event horizon.

March 24, 2020March 24, 2020 by Matt Williams

How Researchers Produce Sharp Images of a Black Hole

In April of 2019, the Event Horizon Telescope collaboration history made history when it released the first image of a black hole ever taken. This accomplishment was decades in the making and triggered an international media circus. The picture was the result of a technique known as interferometry, where observatories across the world combined light from their telescopes to create a composite image.

This image showed what astrophysicists have predicted for a long time, that extreme gravitational bending causes photons to fall in around the event horizon, contributing to the bright rings that surround them. Last week, on March 18th, a team of researchers from the Harvard-Smithsonian Center for Astrophysics (CfA) announced new research that shows how black hole images could reveal an intricate substructure within them.