A groundbreaking discovery by a team of international physicists, including researchers from Washington University in St. Louis, has revolutionized our understanding of black holes. The team’s innovative use of a high-altitude telescope, known as XL-Calibur, has provided unprecedented insights into the behavior of black holes and their interaction with surrounding matter.
In a recent study, the team focused on Cygnus X-1, a well-studied black hole located approximately 7,000 light-years away. By measuring the polarization of light near the black hole, scientists can gather crucial information about the shape and behavior of the hot gas and debris swirling around it at extreme speeds. This technique allows them to study the black hole’s accretion process and the emission of radiation and energy.
The findings, published in The Astrophysical Journal, include the most accurate measurement to date of the black hole’s hard X-ray polarization. Graduate student Ephraim Gau and postdoctoral research associate Kun Hu, both from WashU, played a significant role in the study. They emphasized the challenge of detecting Cyg X-1 due to its minuscule X-ray light point in the sky, making polarization a valuable tool for understanding the surrounding environment.
The data was collected during a remarkable balloon flight across the Northern Hemisphere in July 2024, which also included measurements of the Crab pulsar and its wind nebula. This flight set multiple technical milestones, showcasing the XL-Calibur’s capabilities. Collaborating with colleagues at WashU and other institutions, including KTH Royal Institute of Technology in Sweden, has been instrumental in these achievements.
Looking ahead, the team plans to expand their research by observing additional black holes and neutron stars during the telescope’s next launch from Antarctica in 2027. By studying a broader range of objects, they aim to create a comprehensive understanding of matter behavior in extreme environments. With the support of NASA grants and the McDonnell Center for the Space Sciences, the team is optimistic about solving longstanding questions in black hole physics in the near future.
This groundbreaking research highlights the power of international collaboration in scientific discovery, pushing the boundaries of our knowledge about the universe and black holes.