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

Astronomy & Astrophysics 59 MEGA SCIENCE VISION-2035 antennas, each of 45 m diameter, spread out over a region of about 30 km diameter, centred at Khodad which is about 80 km from Pune. It operates in a set of frequency bands in the range 110 MHz to 1450 MHz, and supports both an interferometric aperture synthesis mode and a phased array beamformer mode, that can also be used simultaneously. Following the recently completed upgrade in 2019, the GMRT now provides almost seamless frequency coverage from 110 MHz to 1450 MHz, with a maximum instantaneous bandwidth of 400 MHz, offering an increase in sensitivity of three times over the original legacyGMRT. Since it was commissioned, the GMRT has been used by astronomers from more than 40 countries, for a large and diverse range of studies. Every year more than 150 observing proposals are received, involving more than 500 astronomers. About half of the principal investigators for GMRT proposals are fromwithin India while the remaining are from overseas. Over the last 10 years, the average over-subscription factor for the GMRT has been around 2.0. The GMRT represents one of the finest open access research facilities in India that is much sought after by the international research community. The GMRTdata archive which hosts all interferometric observations made with the GMRT since its release as a public research facility in 2002, now houses over 300 TB of data. The archive is publicly accessible through an advanced, searchable web-based interface. More than a hundred download requests are received every month and data are made available to users automatically. Hundreds of gigabytes of data are served to users via a high speed internet link. The GMRT has provided unique contributions to the following areas: (i) statistical detection of H I emission from distant galaxies, (ii) detection of H I 21-cm absorption over a large redshift range, (iii) detection of diffuse radio emission from distant galaxy clusters, (iv) low-frequency detection of pulsars and a wide range of transient sources, (v) discovery of several largest radio sources and (vi) TGSS survey. The upgraded GMRT (uGMRT) is recognized as one of the SKApath finders and is nowbeen part of International Pulsar TimingArray project. In addition to the above, Indian institutions have been involved in some international projects. The RRI has participated in the construction of theMWAobservatory inAustralia, where the RRI team designed and developed the digital receiver system, and astronomers continue to be involved in carrying out key science experiments with the facility. More recently, India (via a set of more than 20 institutions across the country who are members of the SKA India Consortium) is also significantly involved in the upcoming Square KilometreArray (SKA) project as described in detail in a later section. 4.2.2 Optical and InfraredAstronomy Observations in the optical domain have traditionally been pursued in the country, and there have been several important results and discoveries made by Indian astronomers, some of which are highlighted earlier in this document. A suite of 1–4-meter class telescopes are available in the country for observations in the optical and NIR wavelength regions. These are located at the Vainu Bappu Observatory (VBO), Kavalur and the IndianAstronomical Observatory (IAO), Hanle, operated by the IIA; the Naintal and Devasthal Observatories operated by ARIES; Gurushikhar Observatory operated by PRL and the Girawali Observatory operated by IUCAA. Together, these telescopes enable direct imaging and spectroscopic observations over the wavelength range of ~ 3700 Å to 4.0 m, and polarimetric μ