In a recent study published in the journal Nature, an international team of researchers led by Zuobin Zhang from the University of Southampton, along with collaborators from various institutions including the University of Amsterdam, the University of Cambridge, and the University of California, Berkeley, has shed new light on the behavior of black hole X-ray binaries. These systems, where a black hole feeds off a companion star, often emit powerful outflows that can influence their surroundings. The researchers have identified a previously unknown relationship between two primary types of these outflows: X-ray disk winds and relativistic jets.
Accretion onto black holes often leads to the launch of outflows that significantly influence their surrounding environments. The two primary forms of these outflows are X-ray disk winds—hot, ionized gases ejected from the accretion disk—and relativistic jets, which are collimated streams of particles often expelled along the rotational axis of the black hole. While previous studies have revealed a general association between spectral states and different types of outflows, the physical mechanisms governing wind and jet formation remain debated.
The team used coordinated observations from the Neutron Star Interior Composition Explorer (NICER) and the MeerKAT radio telescope to study the recurrent black hole X-ray binary 4U 1630-472. During three recent outbursts, they observed that only one type of outflow was detected at a time, indicating a clear anti-correlation between X-ray disk winds and jets. This exclusivity occurred even as the overall accretion luminosity remained within the range expected for a standard thin disk, characteristic of the canonical soft state.
The researchers suggest that this competition between outflow channels may depend on how the accretion energy is partitioned between the disk and the corona. The corona is a hot, diffuse region of plasma that surrounds the accretion disk. Understanding this interplay could provide new insights into the mechanisms driving these powerful outflows.
For the energy sector, this research could have implications for understanding the behavior of accreting black holes in other contexts, such as active galactic nuclei, which can influence the energy output and feedback processes in galaxies. Additionally, the study highlights the importance of multi-wavelength observations in studying these complex systems, which could inform the development of future observational strategies and technologies.
This article is based on research available at arXiv.