Using data from AstroSat1, India’s first dedicated space astronomy observatory, a group of astrophysicists has discovered aperiodic modulation of high-energy X-ray photons in Swift J1727.8-1613, a black hole binary source.
A black hole and companion star encased in gravitational attraction make up a black hole X-ray binary (BH-XRB) system. A bright accretion disk is created as matter from the star is drawn away by the black hole. High-energy X-rays are released and matter that is falling towards the black hole through the accretion disk comes into contact with temperatures in the millions of degrees.
In addition to detecting black holes, BH-XRBs also provide information about the processes involved in accretion, which is the increase in mass of celestial objects due to gravitational forces.
During a seven-day outburst phase of the BH-XRB, the observations showed that the Quasi-Periodic Oscillation (QPO) frequency of high-energy photons increased from 1.4 Hz to 2.6 Hz. The “unique phenomenon” was discovered for the first time in a BH-XRB, according to a Monday statement from the Indian Space Research Organization (ISRO).
QPOs shed light on the gravitational pull of black holes and contribute to a deeper understanding of their fundamental features and accretion dynamics.
Astrophysicists from the Indian Institute of Technology, Guwahati, University of Mumbai, U R Rao Satellite Centre/ISRO, and Tata Institute of Fundamental Research published their results in the globally journal Monthly Notices of the Royal Astronomical Society.
NASA’s Swift Burst Alert Telescope found Swift J1727.8-1613 in August 2023, and it was later determined to be one of the brightest sources. On September 2, AstroSat made the initial observation of the source; a week later, on September 8-14, observations were conducted.
According to ISRO, the astrophysicists examined the QPO variability at higher energies using the Large Area X-ray Proportional Counter onboard AstroSat. In order to better understand the source’s the spectrum energy distribution, they used observational data from the Neutron Star Interior Composition Explorer, an observatory on board the International Space Station.
