Astronomers announce the discovery of supermassive black holes

Two supermassive black holes orbit each other in a binary system. They are 10 times closer to each other than the black holes in the only other known binary supermassive black hole system. Credit: Caltech / R. Hurt (IPAC)

A team of researchers from Purdue University and other institutions has discovered a massive mass[{” attribute=””>black hole binary system, one of only two known such systems. The two black holes, which orbit each other, likely weigh the equivalent of 100 million suns each. One of the black holes powers a massive jet that moves outward at nearly the speed of light. The system is so far away that the visible light seen from Earth today was emitted 8.8 billion years ago.

The two are only between 200 AU and 2,000 AU apart, at least 10 times closer than the only other known supermassive binary black hole system. One AU is the distance from the Earth to the sun, which is about 150 million kilometers (93 million miles) or 8.3 light minutes.

The close separation is significant because such systems are expected to merge eventually. That event will release a massive amount of energy in the form of gravitational waves, causing ripples in space in every direction (and oscillations in matter) as the waves pass through.

Finding systems like this is also important for understanding the processes by which galaxies formed and how they ended up with massive black holes at their centers.

Brief summary of the methods

The researchers discovered the system by chance when they noticed a recurring sinusoidal pattern in radio brightness emission differences over time, based on data taken after 2008. A subsequent search of historical data revealed that the system was also changing in the same way in the late 1970s to early 1980s. This kind of variance is exactly what researchers would expect if a stream emission from one black hole was affected by the Doppler effect due to its orbital motion as it oscillated around the other black hole. Matthew Lister of Purdue University’s School of Science and his team imaged the system from 2002 to 2012, but the team’s radio telescope lacks the resolution needed to resolve individual black holes at such a large distance. Its imaging data supports the binary black hole scenario and also provides the directional angle of the outflow outflow, which is an important component of the leaf model for Doppler-induced changes.

Two supermassive black holes are seen orbiting each other in this artist’s loopable animation. The most massive black hole, hundreds of millions of times the mass of our Sun, releases jets that change in apparent brightness as the duo orbit each other. Astronomers found evidence of this scenario at a quasar called PKS 2131-021 after analyzing 45 years of radio observations showing the system periodically dimming and brightening. The observed periodic pattern is believed to result from the orbital motion of the jet. Credit: Caltech / R. Hurt (IPAC)

Experience of Purdue University Professor

Matthew Lister, Professor of Physics and Astronomy, Purdue University School of Science, specializes in his research in the following areas: active galactic cores, astrophysical jets and shocks, quasars and BL Lacertae objects, narrow-striped Seyfert I galaxies, and very long fundamental interferometry.

For more information about this study:

Reference: “Unexpected phenomena of Blazar PKS 2131–021: a unique candidate for a supermassive black hole” by S.O’Neill, S. Kiehlmann, ACS Readhead, MF Aller, RD Blandford, I. Liodakis, ML Lister, P . Mróz, C. P. O’Dea, T. J. Pearson, V. Ravi, M. Vallisneri, K. A. Cleary, M. J. Graham, K. B. Grainge, M. W. Hodges, T. Hovatta, A. Lähteenmäki, J. W. Lamb, T. J. W. Lazio, W. Max-Moerbeck, V. Pavlido, T. Prince, R. A., Reeves, M. Astrophysical Journal Letters.
DOI: 10.3847 / 2041-8213 / ac504b

Funding: includes support for the MOJAVE program[{” attribute=””>NASA-Fermi grants 80NSSC19K1579, NNX15AU76G and NNX12A087G.