By | Syed Safa Chishti
Srinagar: A new discovery has led Indian scientists to reveal astonishing details over detecting radio signals emitted by neutral atomic hydrogen gas that now can show distant galaxies in the universe from such emissions, as announced by Director at National Centre for Radio Astrophysics (NCRA), Pune Yashwant Gupta.
With the data taken from Giant Metrewave Radio Telescope (GMRT) at Pune, scientists from the Indian Institute of Science (IISc), Bengaluru, and McGill University, Canada, detected a radio signal emitted by the atomic hydrogen in the Milky Way at redshift (z= 1.29), in extremely distant galaxy. Insights from the findings show that the astronomical distance where the signal was detected has been the farthest ever been detected. This revelation confirmed a strong lensing of 21 cm emission from a galaxy. These findings are published in the Monthly Notices of the Royal Astronomical Society.
“The detection of neutral hydrogen in emissions from the distant universe is extremely challenging and has been one of the major science goals of the Giant Metrewave Radio Telescope (GMRT). We can now catch a glimpse of the galaxy that existed billions of years ago. It will enable one to look back in time. It allows us to reconstruct the history of the universe,” Gupta added.
The findings revealed how the detected signal tuned in shifting back into time through source of 8.8 billion years. Later when the signal travelled from the source to the telescope, the 21 cm emission line had red shifted to 48 cm. This detection came into function through a phenomenon termed as ‘gravitational lensing’, in which the light emitted by a source emerged out bent due to the gravitational force of another intervening massive body between the target galaxy and the observer. The process resulted into the ‘magnification’ of the signal.
Assistant Professor, Department of Physics, IISc, Nirupam Roy highlighted the significance of the case by stating the magnification of the signal as attained to be about a factor of 30, which has allowed to see through the high redshift universe.
The research was funded by McGill and IISc and a Giant Meterwave Radio Telescope is built and operated by NCRA-TIFR.