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

Astronomy & Astrophysics 27 Major technological developments that helped the 10-meter class telescopes to achieve their success include: segmented mirror technology, adaptive optics, integral field spectroscopy and optical interferometry. In order for the extremely large telescopes to be successful, it is important to (1) obtain suitable segmented mirror technology to operate a coherent 30-meter aperture, (2) be able to produce sharp images over a large field of view and (3) build highly multiplexed instruments to utilise every photon collected by the telescope. It is expected that, in the era of the extremely large telescopes, the 10-meter class telescopes will play an important role as survey instruments and instruments for followup studies. The Indian astronomy community has limited access to the existing 10-meter class telescopes either through competitive international time allocation process or through archival data. This has prevented the Indian community in getting early access to some discovery space. However, this is expected to change in the coming decade as India is now one of the partners of the TMT observatory with ~10% share in the project. Our participation in this project has enabled us to participate in the development of some of the major science projects and technologies (as detailed later in this document). However, to achieve maximum benefits it is also important for the Indian community to have access to a 10-meter class telescope fitted with a range of state-of-the-art instruments. 3.1.2 SpaceObservatories Hubble Space Telescope: The Hubble Space Telescope (HST) is a 2.4-meter telescope in space performing observations in the far-UV (i.e. ~1200Å) to near-IR (2.2 µ m). Despite its small size and in operation for nearly three decades, the HST consistently outperforms many of the most advanced ground-based telescopes (thanks to its high resolution imaging capabilities without being affected by the atmospheric blurring) and is still considered the pinnacle of optical and ultraviolet astronomy, with a heavy demand for its use, greatly exceeding the available observing time each year. HST played an important role in measuring the expansion rate (or Hubble constant) of the Universe at an unprecedented 2.2% accuracy. This measured expansion rate corresponds to an age for the Universe of 13.8 billion years. HST observations played an important role in creating a robust “distance ladder” based on nearby parallax, Cepheid variables, and distant supernovae. All these observations led to the discovery of the accelerated expansion of the Universe and the idea of “Dark Energy”. Interestingly, the Hubble constant estimates from cosmic microwave background experiments do not agree with those based on HST and other ground based observations. Resolution of this so called “Hubble-Tension” is an important endeavour in the coming years. Dedicated deep field observations using HST (Hubble Deep Field, Hubble Ultra Deep Field, Hubble Deep UV Legacy Survey and Frontier fields) unveiled the details of the evolving universe, tracked the star formation in galaxies over billions of years, and documented the period over which star formation activity in our Universe had a peak, which was about 3 billion years after the Big Bang. Using the gravitational lensing effects, “the frontier field” observations pushed our ability to detect fainter objects which enabled us to gain insights into the contents of the Universe at farther and farther distances (earlier and earlier in cosmic history). Programmes such as Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) have allowed one to investigate the distribution and evolution of galaxy morphology, galaxy clustering andmergers in the early Universe. Data collected from these observations • • MEGA SCIENCE VISION-2035