In April of 2019 the Event Horizon Telescope (EHT) released the first image of the immediate environment around a black hole in M87. This image shows a ring-shaped “shadow,” predicted by General Relativity to be caused by the bending of light around the black hole. This image will usher in a new era of studying precision black hole physics on horizon scales. Given this and other developments, the focus of this study is on assessing how space-based approaches may address pressing questions in black hole science over the coming decade.
A goal of the KISS study will be to explore fundamental questions in black hole physics, and determine which new measurements, as well as new directions, will allow us to answer those questions. In particular, the study will review the science motivation for event horizon scale probes, assess and explore techniques to connect observations to the underlying black hole physics, and explore what ancillary science might be possible with future space-enhancements to Earth-based arrays like the EHT. This study will adopt a “Science Traceability Matrix” (STM) approach for future horizon scale black hole studies.
Once fundamental science goals have been identified, we will explore instrumental and algorithmic enhancements that will lead to the capabilities required to gain traction on these goals. As one example, we will evaluate the possibility of improving instrumentation and imaging algorithms to study black holes evolving on short timescales. Studying dynamical processes that govern black hole accretion, relativistic jets, and the magnetic field structures at an event horizon requires that we analyze measured data of a black hole with a time resolution finer than orbital period of its circling gas. Our Galactic Center supermassive black hole, SgrA*, is the prime candidate to study these processes as it is evolving on short time scales. However, since SgrA* varies dramatically over a night, imaging approaches that were used for M87 will perform poorly. In this KISS study, we will explore expanding the EHT with one or more orbiting antennas, which with short orbital periods would lead to a much improved VLBI array.
This study will join experts in data science, astronomy, and space science to explore innovative approaches for doing black hole science that tightly integrates novel sensor and algorithm design.