Introduction
Radio #Telescopes are used in the field of Astronomy to observe the electromagnetic waves emitted by celestial objects. As we all know, most astronomical objects cannot be viewed with bare eyes. The radiations emitted by the astronomical objects fall in the Radiofrequency range. Telescopes use optical lenses to get an image of the celestial objects whereas #Radiotelescopes use large antennas that absorb Radio frequencies emitted by the objects in the sky to study them.
#Radio telescopes have vast and wide antennas that help capture the radio energy emitted by celestial objects even at a very far distance. Telescopes can only be used in the day time as they require a light source that reflects on the object whose image we try to view through the lenses. Unlike normal telescopes, radio telescopes can be used for observations even during night time.
Given the basic introduction about Telescopes and Radio Telescopes, let us now focus on what a Giant Metre Wave #Radiotelescope is and how it differs from the previously described telescopes.
Giant Metre Wave Radiotelescope (GMRT)
As the name suggests, #GMRTs are Radio telescopes with larger antennas and wider range to cover for observation. Astrophysical principles are used to build these antennas. Devices like these require high angular precision so that we acquire a high-resolution image based on the radio frequencies absorbed. A set of Telescopes are built over a wide area and the number of telescopes/antennas are built based on the calculations done keeping in mind the #astrophysical principles.
Components and arrangement of the telescope.
There are over 30 antennas of 45m in diameter each. A land area for a baseline of 25km is allotted for building these antennas. Nearly half of the antennas are situated randomly in an area of one square kilometer. The rest of the #antennas as arranges in a Y-shape. This configuration of the antennas requires a larger area than the randomly arranged ones. The arrangement as discussed above enables the signals to be correlated and form an image synthesized by the radio #signals.
Working of the Telescope.
The GMRT is a combination of all the antennas/telescopes built. When the antennas receive the radio signals, the correlation of radio signals happens to form multiple pairs of #interferometers (an instrument that merges two light sources and forms interference patterns that can be measured and analyzed) that will take hours of time to generate an image of the celestial body emitting the radio energy/signals.
The telescopes connected thus work with six different frequencies which are approximately 50, 153, 233, 325, 610, and 1420 MHz. The design of the GMRT is called the `SMART' concept - for Stretch Mesh Attached to Rope Trusses.
Main objectives and applications of GMRT
Protoclusters are low-mass galaxies that have a relationship with high-redshift clusters using simulation models like Millenium Simulation with the semi-analytic model.
GMRT is used to recognize the highly redshifted spectral line of neutral hydrogen expected from the protoclusters or protogalaxies. These spectral lines need to be detected before they are condensed to form galaxies.
Pulsars are compact stars that emit electromagnetic radiation from magnetic poles. Pulsars are emitted from galaxies. GMRT is also used to study the pulsars in our galaxy.
GMRT Observatory in India
The Giant Metrewave Radio Telescope (GMRT) Observatory is set up by the National Center for Radio Astrophysics. It is a division of the Tata Institute of Fundamental Research, Mumbai. The GMRT Observatory is situated at Khodad which is around 80km north of Pune. The observatory is not situated far from the field where the telescopes/antennas are built.
Research related to GMRT
The pulsar research is going to take place at meter wavelengths which will help the Pulsars in the sky and study them. Currently, the research is taking place in Pune, India. The GMRT houses more digital equipment such as a correlator and a pulsar receiver to carry out the observation and research.
For more information and updates on the device, visit the official website of NCRA.
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