High-resolution imaging for advances in astronomy

Two physical phenomena, (i) diameter of the collecting area of a telescope and (ii) turbulence in the atmosphere which introduces fluctuations in the index of refraction along the light beam, limit the minimum resolvable angle at optical and infrared wavelengths. Sharpness of astronomical images thus obtained can be significantly enhanced by using a back end adaptive optics system which reduces the incoming wavefront distortion by suitably deforming a mirror in real-time, and speckle interferometry which is a post-processing technique. The Nobel prize-2020 in physics award to astronomers has recognised the efforts of using these techniques. After a short description of the black hole, this article elucidates the methodology employed to identify such an object having a mass of about 4 million solar masses.