MSV-2035 Astronomy Document - Inside Design - FINAL - FINAL

Astronomy & Astrophysics 49 Analysis of large scale structures using archival observations has been used to demonstrate the existence of a supercluster, named the Saraswati supercluster. This has been shown to be made up of a large number of clusters of galaxies and is one of the largest concentrations of galaxies of this size known till date. Apart from the usual statistical indicators of amplitude of clustering to characterize the large scale structure, topological constructs such as Minkowski functionals have been used to compare different models with observations. Similar techniques have been applied to study the distribution of radio sources in the sky and the cosmicmicrowave background radiation. Indian astronomers have also made significant progress in developing and deploying methods that can be used for intensity mapping: a technique for tracking mass distribution using emission lines from atomic or molecular gas as a tracer. 4.1.10 CosmicMicrowave BackgroundRadiation The CMBR was predicted by George Gamow in the context of the Big Bang model of cosmology. This was observed by Penzias and Wilson who went on to get the Nobel prize for this discovery. Anisotropies in CMBR were predicted early on and detailed predictions were made in the context of inflationary models. These were detected observationally by COBE (COsmic Background Explorer) in 1992. Theoretical predictions and comparison with observations is based on a robust mathematical foundation. Indian scientists have contributed considerably to ideas and models, as well as detailed programs of comparison of theoretical models with observations to test fundamental aspects as well as detailed constraints on parameters of models. Fundamental aspects here refer to assumptions of isotropy, as well as statistical isotropy of perturbations. Whereas the program to constrain parameters focuses on the description of the Universe as well as the characteristics of perturbations that go on to give rise to the large scale structure and galaxies. Indian astronomers have made significant progress inmeasuring the spectrumof radiation backgrounds, including the cosmic microwave background radiation. This requires development of broad-band receivers and detectors that have a uniform angular response over a wide range of frequencies. These are being used tomeasure that spectrum as this can yield considerable information about the epoch of recombination and the epoch of reionization, leading to an improved knowledge of various cosmological parameters and scenarios of galaxy formation. Indian astronomers played a key role in confirming one of the fundamental predictions of Big Bang, that of increasing temperature of CMBR with redshift. Using the limits on the deviation of CMBR spectrum from a perfect blackbody (the so called “spectral distortions”), interesting constraints on cosmological parameters and contributions to CMBR from sources like decaying darkmatter etc., were placed. 4.1.11 Cosmology and the EarlyUniverse Observational evidence indicates that the Universe is undergoing an accelerated expansion at present. This is believed to be driven by dark energy, a component with unusual properties like an effective negative pressure. This component dominates the Universe at present. Considerable work has been done on modelling dark energy and its observable properties by groups in many different universities and institutes. Many groups have used a wide variety of observations and statistical tools to constrain properties of dark energy. A key question of whether observations can differentiate between different classes of models has also been addressed recently. Observations also suggest that the MEGA SCIENCE VISION-2035