The Ministry of Science & Technology announced a significant astronomical research achievement involving a decade-long study of the binary black hole system OJ 287. An international team of 106 scientists from 18 countries, coordinated by scientists from Aryabhatta Research Institute of Observational Sciences (ARIES), conducted optical observations of the blazar between 2015 and 2025 using two dozen telescopes.
OJ 287 is a rare astronomical object located approximately 4 billion light years from Earth that contains two supermassive black holes orbiting each other in a twelve-year cycle, forming a binary system. The blazar produces powerful jets of plasma moving at nearly light speed directed toward Earth and shows a distinctive double-peaked pattern in brightness over time, a periodic behavior first discovered in 1988 using optical observations dating back to 1880.
The study produced the most extensive and densely sampled optical time-series data of OJ 287 obtained over the past 150 years, tracking how the object evolved across different timescales from long-term changes spanning years to rapid variations occurring over shorter periods. Using eight optical spectra taken during low-flux states from October 21 to November 22, 2017, from Steward Observatory in the USA, the research team estimated the central black hole mass to be at least 3.89 billion solar masses based on the [O III] emission line width.
The findings provide insights into the emission mechanism of this binary black hole system and expand the scientific scope of OJ 287 beyond the study of its binary nature, contributing to multimessenger astronomy which involves coordinated simultaneous observations across different electromagnetic bands. The research strengthens understanding of OJ 287 as a dynamic cosmic laboratory for studying relativistic jets, supermassive binary black hole behavior, and potential connections between electromagnetic and gravitational-wave signals.