Mystery of Black hole X-ray binary systems

The AstroSat observatory has been instrumental in uncovering mysteries surrounding black hole X-ray binary systems, shedding light on the complex processes occurring within these enigmatic cosmic phenomena. Here’s an overview of the significance of this discovery:

1. AstroSat Observatory: AstroSat is India’s first dedicated multi-wavelength space observatory, launched in September 2015. It is designed to observe celestial objects in various wavelengths, including ultraviolet, optical, and X-ray.
2. Black Hole X-ray Binary Systems: These systems consist of a stellar-mass black hole and a companion star. Material from the companion star gets accreted onto the black hole, releasing vast amounts of energy in the form of X-rays, which can be detected by telescopes like AstroSat.
3. Unraveling Mysteries: By observing black hole X-ray binaries across different wavelengths, AstroSat has provided valuable insights into the physics of these systems. It has helped astronomers understand the processes involved in the accretion of matter onto black holes and the emission of X-rays.
4. Understanding Black Hole Properties: Studying X-ray emissions from black hole X-ray binaries allows astronomers to infer properties such as the mass of the black hole, the rate of accretion, and the geometry of the accretion disk. These observations contribute to our broader understanding of black hole physics and the evolution of binary star systems.
5. Contributions to Astrophysics: The discoveries made by AstroSat in the realm of black hole X-ray binaries have broader implications for astrophysics. They provide insights into the mechanisms driving the high-energy processes observed in compact stellar-mass black holes, as well as their role in shaping the dynamics of galaxies and the universe at large.

The recent study conducted by an international team of scientists, facilitated by India’s AstroSat observatory, sheds light on the enigmatic nature of the X-ray binary system MAXI J1820+070, which is home to a black hole. Here’s a summary of the key findings and contributions of the study:

1. MAXI J1820+070 X-ray Binary System: MAXI J1820+070 is identified as a low-mass X-ray binary system housing a black hole as its compact entity. X-ray binaries consist of a normal star and a collapsed star, emitting X-rays due to accretion processes.
2. Study Title and International Collaboration: The study, titled “A Multi-Wavelength Spectral Study of MAXI J1820+070 in the Soft and Hard States,” involved collaboration among researchers from India, the United Kingdom, Abu Dhabi, and Poland. It was spearheaded by scientists from the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune.
3. Data Acquisition: The study utilized data obtained from AstroSat’s three X-ray payloads and UV telescope, capturing soft and hard X-ray emissions as well as far ultraviolet radiation from MAXI J1820+070. Additionally, optical data from the Las Cumbres Observatory and soft X-ray data from NASA’s NICER mission were incorporated.
4. Proximity and Luminosity: MAXI J1820+070 is positioned at a distance of 9,800 light-years from Earth. It gained significant attention within the astronomy community due to its remarkable luminosity during its 2018 outburst, becoming the second brightest object in the X-ray sky.
5. Accretion States and Black Hole Spin: The study provides insights into the accretion states of MAXI J1820+070 throughout its outburst. By employing advanced techniques, the researchers were able to discern the spin of the black hole, thereby revealing fundamental properties of the system.
6. AstroSat’s Contribution: The study underscores the pivotal role of AstroSat in advancing the understanding of transient black hole X-ray binaries. Its multi-wavelength capabilities allowed for a comprehensive analysis of MAXI J1820+070, contributing to a deeper understanding of such systems.

Overall, this study exemplifies the collaborative efforts of international scientists facilitated by AstroSat, leading to significant insights into the dynamics and properties of black hole X-ray binary systems like MAXI J1820+070.