Giant Metrewave Radio Telescope in Pune helps detect atomic hydrogen from far-away galaxy

Subject :Science and Technology

Section :Space

Context:

A radio signal originating from atomic hydrogen in an extremely distant galaxy was detected by the Giant Metrewave Radio Telescope (GMRT) located in Pune. This is the largest astronomical distance over which such a signal has been picked up.

Giant Metrewave Radio Telescope (GMRT):

GMRT is a low-frequency radio telescope that helps investigate various radio astrophysical problems ranging from nearby solar systems to the edge of the observable universe.
GMRT is an array of thirty fully steerable parabolic radio telescopes of 45-meter diameter.
It is operated by the National Center for Radio Astrophysics of the Tata Institute of Fundamental Research (NCRA-TIFR).
GMRT is an indigenous project. Its design is based on the `SMART’ concept – for Stretch Mesh Attached to Rope Trusses.
It functions at the meter wavelength part of the radio spectrum because man-made radio interference is considerably lower in this part of the spectrum in India and there are many outstanding astrophysics problems which are best studied at metre wavelengths.
The location for GMRT, Pune meets several important criteria such as low man-made radio noise, availability of good communication, vicinity of industrial, educational and other infrastructure and, a geographical latitude sufficiently north of the geomagnetic equator in order to have a reasonable quiet ionosphere and yet be able to observe a good part of the southern sky as well.

Atomic Hydrogen:

Atomic hydrogen is the basic fuel required for star formation in a galaxy.
When hot ionised gas from the surrounding medium of a galaxy falls onto the universe, the gas cools and forms atomic hydrogen.
This then becomes molecular hydrogen and eventually leads to the formation of stars.

What information does atomic hydrogen hold about the source region?

Information about atomic gas content in nearby and distant galaxies.
Age of the universe, tracing the past events (events as old as 8.8 billion years old.)
Mass of the galaxies, mass of atomic hydrogen present in those galaxies.

Significance of this discovery:

These results demonstrate the feasibility of observing atomic gas from galaxies at cosmological distances in similar lensed systems with a modest amount of observing time.

What is Redshift?

Redshift represents the signal’s wavelength change depending on the object’s location and movement; a greater value of z indicates a farther object.