To do this, scientists have provided transformative observations of the black hole Cygnus X-1 which is about 7,000 light-years from Earth. Utilizing a balloon-borne telescope named XL-Calibur, the research team has captured the most precise measurement of hard X-ray polarization from this celestial body to date. This research has improved our understanding of the fundamental physical processes at work close to black holes. It has since been accepted for publication in The Astrophysical Journal.
Henric Krawczynski, a distinguished professor of physics at Washington University in St. Louis (WashU), is the team’s principal investigator. These were groundbreaking observations used to validate computer simulations of collisions that model particle infall, interaction, and emission in the extreme environments surrounding black holes. This collaborative work, with graduate student Ephraim Gau and postdoctoral research associate Kun Hu pairing up on it, has contributed conceptually and theoretically. Both were joint corresponding authors on the published paper.
Researchers used a novel combination of theory and observation to learn more about the polarization of X-rays emitted from Cygnus X-1. This information is a key piece of the puzzle to truly grasp this tumultuous black hole dance. Krawczynski emphasized the importance of these observations, stating, “The observations we made will be used by scientists to test increasingly realistic, state-of-the-art computer simulations of physical processes close to the black hole.”
Along with Ephraim Gau, he shed some light on the huge challenges of imaging such distant cosmic phenomena. “If we try to find Cyg X-1 in the sky, we’d be looking for a really tiny point of X-ray light,” he explained, highlighting the intricacies involved in astrophysical research.
The researchers emphasized the value of polarization for imaging regions around black holes. This is doubly important when direct imaging from Earth becomes impossible. “Polarization is thus useful for learning about all the stuff happening around the black hole when we can’t take normal pictures from Earth,” Gau remarked.
The team is looking forward to enriching their research with data from NASA satellites, including IXPE. They hope to find new answers to old questions surrounding black holes. Krawczynski expressed optimism for future research, stating, “Combined with the data from NASA satellites such as IXPE, we may soon have enough information to solve longstanding questions about black hole physics in the next few years.”
The XL-Calibur telescope’s next round of observations will take place in 2027 when it will be launched from Antarctica. The team is eager to catch light from many more black holes and neutron stars. This pioneering research will deepen our knowledge of these enigmatic cosmic objects.