Chandrasekhar Hall

Probing the Universe at Radio Wavelengths: from the GMRT to the SKA

Yashwant Gupta

NCRA-TIFR

Today, one can study the Universe in different parts of the electromagnetic spectrum,
from radio to gamma rays. We will see how radio astronomy, which started in the 1940s,
has become an integral part of the astronomer's tool-kit. We will look at how a
radio telescope functions, and the basic ideas and techniques that are important in
this field. We will also explore what kind of exotic objects and secrets of the Universe can be explored with radio astronomy.

As a case study that illustrates many of the above concepts, we will take a close
look at our own Giant Metrewave Radio Telescope (GMRT) -- one of the largest metre
wavelength radio telescopes in the world today. The GMRT, which works in five
discrete bands in the frequency range of 150 MHz to 1500 MHz, with a maximum
instantaneous bandwidth of 32 MHz, has been in successful operation for the last 13
years, and has produced many new and interesting science results and discoveries.
We will look at the engineering complexities behind the working of this major
facility, and also highlight some of the important and interesting new results
it has produced. The GMRT is presently undergoing a major upgrade that will
significantly improve its capability and keep it on the forefront of international
research in astrophysics; we will look at the promises this holds out, as well as
some of the technological challenges it poses.

Looking further into the future, we will also talk briefly about the SKA (Square
Kilometre Array) project -- a next generation international radio telescope -- and
Indian participation in this mega-project.