A black hole is stirring up excitement in the astronomy world. This particular black hole, called IGR J17091-3624, is located about 28,000 light-years away. Its unusual “heartbeat,” marked by rhythmic brightness pulses, is prompting scientists to rethink how black holes behave.
NASA’s Imaging X-ray Polarimetry Explorer (IXPE) has been observing this black hole. IGR J17091-3624 pulls in material from a nearby star, creating a swirling disk of superheated plasma around it. The high temperatures in this disk and its surrounding region, known as the corona, produce bright X-ray emissions.
In a recent study, IXPE measured the polarization of the black hole’s X-rays—this gives scientists clues about how the X-rays are aligned and the physical structure of the area around the black hole. Surprisingly, IXPE recorded a polarization degree of 9.1%, significantly higher than what scientists expected. This unexpected data has caught the attention of researchers who study black holes.
Understanding polarization helps in seeking details about the black hole’s environment. A high polarization degree usually implies that the corona’s structure is seen from an edge-on perspective. However, other data from IGR J17091-3624 don’t support this idea, leading to a puzzling contradiction.
Researchers are exploring two popular theories to solve this mystery. The first theory suggests that winds from the accretion disk might scatter the X-rays, creating higher polarization without needing an edge-on view. The second theory proposes that the corona itself is moving outward at incredible speeds, which could amplify the polarization through relativistic effects. Both theories, while complicated, question longstanding beliefs about black holes.
Maxime Parra from Ehime University, who co-authored the study, emphasized that understanding these winds is crucial for grasping how black holes grow. He believes future observations might bring even more surprising data.
These findings were published on May 27 in the Monthly Notices of the Royal Astronomical Society. As we continue to learn more about black holes, studies like this help clear up the mysteries of our universe.
For further information, you can visit NASA’s official statement on IXPE.
