The Giant Metrewave Radio Telescope (GMRT), located near
Narayangaon,
Pune in India, is an array of thirty fully steerable parabolic
radio telescopes of 45 metre diameter, observing at metre
wavelengths. It is the largest and most sensitive radio telescope array in the world at low frequencies.[1] It is operated by the National Centre for Radio Astrophysics (NCRA), a part of the
Tata Institute of Fundamental Research,
Mumbai. It was conceived and built under the direction of
Govind Swarup during 1984 to 1996.[2] It is an
interferometric array with baselines of up to 25 kilometres (16 mi).[3][4][5] It was recently upgraded with new receivers, after which it is also known as the upgraded Giant Metrewave Radio Telescope (uGMRT).[6]
GMRT has produced an all sky survey named
TIFR GMRT Sky Survey (TGSS). Nearly 90% of the sky has been imaged at the frequency of 150 MHz (wavelength 2m), with an angular resolution of 25 arc second and rms noise of 5 mili Jansky per beam. Source Catalogue and FITS image files for the scientific community are freely available.[31] General public and citizen scientists can see 150 MHz image of any, supernova remnant, spiral galaxy or radio galaxy with its name or position at the
RAD@home RGB-maker web-tool. Power and versatility of the GMRT has led to a renaissance in the field of low frequency radio astronomy.[32]
From this, TGSS survey, data, in August 2018, the most distant known radio galaxy : TGSS J1530+1049, located at a distance of 12 billion light years, was discovered by GMRT.[33][34]
In February 2020, it helped in the observation of evidence of the largest known explosion in the history of the universe, the
Ophiuchus Supercluster explosion.[35]
In January 2023, the telescope picked up a radio signal (21 cm line emission from neutral atomic hydrogen gas) which originated from 8.8 billion light years away.
[36]
Activities
Each year on
National Science Day the observatory invites the public and pupils from schools and colleges in the surrounding area to visit the site where they can listen to explanations of radio astronomy, receiver technology and astronomy from the engineers and astronomers who work there. Nearby schools/colleges are also invited to put their individual science experiments in exhibition and the best one in each level (primary, secondary school and Jr. college) are awarded.
Visitors are allowed into GMRT only on Fridays in two sessions - Morning (1100 hrs - 1300 hrs) and Evening (1500 hrs to 1700 hrs).
^Ishwara-Chandra, C H; Rao, A Pramesh; Pandey, Mamta; Manchanda, R K; Durouchoux, Philippe (2005). "Low Frequency Radio Observations of GRS1915+105 with GMRT". Chinese Journal of Astronomy and Astrophysics. 5 (S1): 87–92.
arXiv:astro-ph/0512061.
Bibcode:
2005ChJAS...5...87I.
doi:
10.1088/1009-9271/5/S1/87.
^Swarup, G., Ananthkrishnan, S., Kapahi, V.K., Rao, A.P., Subrahamanya, C.R., and Kulkarni, V.K. (1991) "The Giant Metrewave Radio Telescope", Current Science, vol. 60, pages 90-105.
^Ghosh, A.; Prasad, J.; Bharadwaj, S.; Ali, Sk. S.; Chengalur, J. N. (1 April 2013). "VizieR Online Data Catalog: Complete 150MHz GMRT source catalogue (Ghosh+, 2012)". VizieR On-line Data Catalog. 742.
Bibcode:
2013yCat..74263295G.
^Ali, Sk Saiyad; Ghosh, Abhik; Bharadwaj, Somnath; Choudhuri, Samir (21 December 2014). "Visibility-based angular power spectrum estimation in low-frequency radio interferometric observations". Monthly Notices of the Royal Astronomical Society. 445 (4): 4351–4365.
arXiv:1409.7789.
Bibcode:
2014MNRAS.445.4351C.
doi:
10.1093/mnras/stu2027.
ISSN0035-8711.
^Choudhuri, Samir; Bharadwaj, Somnath; Ali, Sk. Saiyad (2014). "Foreground simulation and power spectrum estimation for 610 MHz GMRT observations". Astronomical Society of India Conference Series. 13: 315–317.
Bibcode:
2014ASInC..13..315C.
^Chatterjee, Suman; Bharadwaj, Somnath (1 February 2019). "On the prospects of measuring the cosmic dawn 21-cm power spectrum using the upgraded Giant Metrewave Radio Telescope (uGMRT)". Monthly Notices of the Royal Astronomical Society. 483 (2): 2269–2274.
arXiv:1804.00515.
Bibcode:
2019MNRAS.483.2269C.
doi:
10.1093/mnras/sty3242.
ISSN0035-8711.
^Dutta, Prasun; Choudhuri, Samir; Pal, Srijita; Bharadwaj, Somnath (11 March 2019). "A Tapered Gridded Estimator (TGE) for the multifrequency angular power spectrum (MAPS) and the cosmological H i 21-cm power spectrum". Monthly Notices of the Royal Astronomical Society. 483 (4): 5694–5700.
arXiv:1812.08801.
Bibcode:
2019MNRAS.483.5694B.
doi:
10.1093/mnras/sty3501.
ISSN0035-8711.