Colour Movies of Black Holes: Understanding Black Hole Astrophysics from the Event Horizon to Galactic Scales

Introduction

Black holes (BHs) are icons of the fundamental nature of gravity, the mysterious force shaping the Universe. They are also the Universe’s most efficient powerhouses, turning infalling gas into energy and outflows that, together with gravity, mold galaxies and thus ultimately stars and planets.

The first image of a black hole by the Event Horizon Telescope (EHT), wherein we played a leading role, captured the imagination of scientists and the public alike. This picture of the immutable black hole is, however, blurred by the dynamic, still mysterious behavior of the surrounding gas. Our limited understanding of these turbulent, magnetized plasma in/outflows, producing the radiation and high-energy particles we observe, obstructs a straightforward interpretation of the black hole image for testing theories of gravity.

Challenges in Understanding Black Holes

The challenge in understanding the astrophysics of black holes and their impact on the cosmos is that they span:

1. More than 8 orders of magnitude in mass, size, and timescales.
2. Emit light over 15 orders of magnitude in frequency.

Our new approach overcomes this scale separation by simultaneously addressing the dynamics of large and small black holes, in color.

Innovative Methodology

We produce for the first time high-resolution multi-color movies with the EHT combined with new telescopes probing the variable extremes of the electromagnetic spectrum (e.g., CTA, MeerKAT/SKA1). The data are analyzed and interpreted with innovative models, finally combining micro- and macrophysics.

Collaborative Expertise

The PIs bring together complementary expertise over the entire black hole mass scale in:

• Radio imaging and multi-wavelength monitoring
• Astroparticle physics
• Theoretical modeling

This collaboration is accompanied by four major investments:

1. Construction of a new mm-wave telescope in Africa enabling full dynamical imaging of black holes with the EHT.
2. New model development.
3. Supercomputing hardware.
4. A vibrant team of young scientists to help develop a new, truly universal black hole paradigm.