In the realm of astrophysics and energy research, a team of scientists led by Dr. C. Pinto from the University of Southampton, along with colleagues from various institutions including the National Institute for Astrophysics in Italy and the University of Toulouse in France, has been investigating the properties of winds in ultra-luminous X-ray sources (ULXs). These sources are fascinating astronomical objects that emit an enormous amount of X-rays, often powered by the accretion of matter onto a compact object like a black hole or a neutron star.
The researchers conducted a multi-year campaign using the XMM-Newton space observatory to study NGC 55 ULX-1, a variable ULX located in the galaxy NGC 55. By performing high-resolution X-ray spectroscopy, they aimed to understand the properties of the winds in this system and their connection to the source’s spectral and temporal behavior. The study, published in the journal Astronomy & Astrophysics, provides valuable insights into the dynamics of these powerful cosmic winds and their role in regulating the accretion process.
The team confirmed the presence of outflows in NGC 55 ULX-1 and characterized the wind using optically-thin plasma models. Their analysis revealed that the emission lines originate from classical X-ray binary disc winds, with low-to-moderate densities and a photoionisation balance. The researchers also identified a slowly moving, cool, and variable plasma associated with a thermal wind. Additionally, they detected mildly-relativistic Doppler shifts in the absorption lines, indicating the presence of powerful, radiatively-driven winds.
One of the most significant findings of this study is the response of the wind to the variability of the underlying continuum. By comparing results obtained at different epochs, the researchers demonstrated that the wind’s behavior can be used to understand the actual accretion regime and the nature of the source. This information is crucial for developing accurate models of accretion processes in X-ray binaries and ULXs.
While this research primarily focuses on astrophysical phenomena, the insights gained from studying these powerful cosmic winds can have practical applications in the energy sector. Understanding the dynamics of accretion and outflows can help improve models of energy generation and transfer in extreme environments, which may, in turn, contribute to the development of more efficient and sustainable energy technologies on Earth. Furthermore, the advanced spectroscopic techniques employed in this study can be adapted for use in various industrial applications, such as monitoring and optimizing energy production processes.
This article is based on research available at arXiv.