4C +37.11

Lore & Background

4C +37.11 is a radio galaxy and elliptical galaxy located about 750 million light years from Earth. Its most notable feature is a pair of supermassive black holes with a separation of 24 light-years (7.3 parsecs), the smallest directly measured separation for such a binary as of 2006. The two black holes have an orbital period of 30,000 years and a combined estimated mass of about 28 ± 8 billion solar masses.

Other candidate binary supermassive black hole systems, such as the quasar OJ 287, are inferred to have even smaller separations based on orbital periods of 12 years, but these have not been directly measured and require additional observation. The eventual collision of the pair in 4C +37.11 is expected to occur at least a few million years from now and would produce strong gravitational waves.

Reader's Guide

The significance of 4C +37.11 lies in its status as the host of the closest directly observed binary supermassive black hole system as of 2006, with a separation of 24 light-years. This direct measurement provides a unique laboratory for studying the dynamics of supermassive black hole pairs before they merge. The system's orbital period of 30,000 years and combined mass of about 28 ± 8 billion solar masses offer concrete data for models of black hole evolution and gravitational wave emission. While other candidates like OJ 287 suggest even closer separations, they remain unconfirmed, underscoring the importance of 4C +37.11 as a benchmark. The eventual merger of this pair, predicted to occur in at least a few million years, will generate strong gravitational waves, linking this system to future gravitational wave observatories. Its legacy is as a key observational anchor for understanding the final stages of supermassive black hole binary evolution.

Did You Know?

• The two supermassive black holes in 4C +37.11 are separated by 24 light-years (7.3 parsecs).
• Their orbital period is 30,000 years.
• The combined mass of the black holes is estimated at 28 ± 8 billion solar masses.
• The eventual collision of the pair is expected to produce strong gravitational waves.