IUCAA Brochure 2024

A unique method has also been used to probe coherence in metal absorption towards multiple images of strong gravitationally lensed quasars. Two of the few currently known quasars with multiple images due to strong gravitational lensing by galaxy clusters at redshift z~0.5-0.6 were studied. The integral field spectroscopic observations of these quasar fields using Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT) facilitated the study of the galaxies associated with the absorbing gas. The results indicate that the metal-enriched gaseous structures around galaxies become less coherent with distance, with a likely coherence length scale of ~10 kpc. A recent work also involves a tomographic analysis of the structure of metal-enriched cool gas in the halos around galaxies at, z<2. Diffuse gas is detected in absorption in the spectra of two background quasars at z~2-3 with angular separations between different pairs of quasar multiple images, enabling us to probe the absorption over transverse physical separations of ~0.4-150 kpc. Further cutting-edge research in this and several other observational challenges will be possible with advanced instruments on the upcoming Thirty Meter Telescope (TMT). From India, IUCAA is playing an important role in this international partnership as part of the India-TMT collaboration. It is leading the development of the Telescope Control System for TMT consisting of several independent software subsystems for running the observatory.