In news: In a first-of-its-kind work, using data from SARAS 3, researchers from the Raman Research Institute (RRI), Bengaluru, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia, along with collaborators at the University of Cambridge and the University of Tel-Aviv, have estimated the energy output, luminosity, and masses of the first generation of galaxies that are bright in radio wavelengths.
- It is called Shaped Antenna measurement of the background Radio Spectrum 3 (SARAS) telescope.
- Indigenously designed and built at Raman Research Institute
- Deployed over Dandiganahalli Lake and Sharavati backwaters, located in Northern Karnataka, in early 2020.
- SARAS 2 was the first to inform the properties of earliest stars and galaxies.
- The results from the SARAS 3 telescope are the first time that radio observations of the averaged 21-centimeter line have been able to determine the properties of radio luminous galaxies formed just 200 million years post the Big Bang ( or Cosmic Dawn) and which are usually powered by supermassive black holes.
- SARAS 3 informs us that less than 3 percent of the gaseous matter within early galaxies was converted into stars, and that the earliest galaxies that were bright in radio emission were also strong in X-rays, which heated the cosmic gas in and around the early galaxies.
- It is used to reject claims of the detection of an anomalous 21-cm signal from Cosmic Dawn made by the EDGES radio telescope developed by researchers from Arizona State University (ASU) and MIT, USA.
- This refusal helped restore confidence in the concordant model of cosmology that was brought into question by the claimed detection.
- The analysis has shown that the 21-cm hydrogen signal can inform about the population of first stars and galaxies.
About the study:
- Scientists study the properties of very early galaxies by observing radiation from hydrogen atoms in and around the galaxies, emitted at a frequency of approximately 1420 MHz.
- The radiation is stretched by the expansion of the universe, as it travels to us across space and time, and arrives at Earth in lower frequency radio bands 50-200 MHz, also used by FM and TV transmissions.
- The cosmic signal is extremely faint, buried in orders of magnitude brighter radiation from our own Galaxy and man-made terrestrial interference.
- Therefore, detecting the signal, even using the most powerful existing radio telescopes, has remained a challenge for astronomers.
- Usage: Even non-detection of this line from the early Universe can allow astronomers to study the properties of the very first galaxies by reaching exceptional sensitivity.
Previous Year Question
Q.1) Consider the following statements: (2018)
- Light is affected by gravity.
- The Universe is constantly expanding.
- Matter warps its surrounding space-time.
Which of the above is/are the prediction/predictions of Albert Einstein’s General Theory of Relativity, often discussed in media?
- 1 and 2 only
- 3 only
- 1 and 3 only
- 1, 2 and 3