Indian astronomy would soon find a new push and aid in the form of the world’s highest and India’s largest gamma-ray telescope, that is going to come up in Ladakh this year. Astronomers would soon be able to observe and monitor spectacular celestial events like explosion of stars, falling of matter into black holes and collision of extraterrestrial objects better, India Science Wire reported.
The new gamma ray telescope is called Major Atmospheric Cherenkov Experiment Telescope (MACE).
The project is a collaboration of scientists from BARC, Tata Institute of Fundamental Research (TIFR) and the Indian Institute of Astrophysics, along with the Electronics Corporation of India Limited.
Placed at 4,300 m above sea level in Hanle, Ladakh, MACE is also the world’s second largest, ground-based gamma-ray telescope with a 21-metre-diameter dish. The largest telescope of the same class is the 28-metre-diameter telescope, which is part of the High Energy Stereoscopic System (HESS) in Namibia.
According to reports, the installation of the telescope is now complete and trial runs are being carried out and will go live later this year.
MACE is equipped with 356 mirror panels and over 1,000 cameras and will detect very short flashes — lasting just a few nanoseconds — of the Cherenkov radiation. All the components of the telescope have been developed in India.
The four-metre telescope will be able to operate in bright environment like twilight hours and moon-lit nights, unlike traditional ones that operate only in dark hours of the night. It will be the second such telescope to be available globally. The first one is in La Palma in Canary Islands set up jointly by Switzerland and Germany in 2011.
What does MACE signify in the field of Astronomy
MACE is named after Russian scientist Pavel Cherenkov, who discovered that charged particles glow when they pass through a non-conducting medium under certain conditions. This phenomenon known as the Cherenkov radiation causes the characteristic blue glow in underwater nuclear reactors. Cherenkov shared the Nobel Prize in Physics in 1958 with Ilya Frank and Igor Tamm for this discovery.
According to some researchers,“The telescope will study different astrophysical sources in energies of 20 GeV to 10 TeV range”.This range will allow scientists to study high-energy processes in the universe. It may also aid the search for dark matter — the mysterious substance that is believed to account for over 80 per cent of the universe’s mass.
Role of Gamma rays
The gamma rays are high energy processes in the universe. Their study will help to understand study of high energy physics close to black holes, compact objects, dark matter and high gravitational fields.
High energy gamma rays emitted from black hole or centers of galaxies, compact objects like pulsars in our galaxy get absorbed in the atmosphere and do not reach the land. But when these rays interact with the atmosphere, the photons give rise to electron–positron pairs and there is a cascade of particles. When the particles move in the atmosphere at very high speed, they give rise to Cerenkov radiation. The blue and ultraviolet Cerenkov light is observed to infer the number of gamma rays hitting the atmosphere.
Gamma rays also provide the best window to study what are called the non-thermal universe. Cosmic rays form an important component of the non-thermal universe. It is thought that remnants of supernova explosions accelerate cosmic rays with energies at the lower end of the cosmic ray spectrum and that higher energy cosmic rays could be accelerated in active galactic nuclei. Gamma rays are also produced when charged particles are accelerated to such high energies through different processes.
Thus the study of the gamma ray emissions from various celestial objects is expected to give a clue regarding the origin of cosmic rays and insights into the emission regions and emission processes in these sources. The details of the new telescope have been discussed in a recent paper published in Journal of Astrophysics and Astronomy.
Moreover, the Earth’s atmosphere blocks most of the incoming gamma rays from space, at a height of 10 kilometres from the surface, which makes it difficult for ground-based telescopes to detect them.
Therefore the telescope is being placed at such a high altitude. Placing the telescope at higher altitudes gives them a significant advantage to observe the Cherenkov radiation, which is produced when cosmic gamma rays strike the Earth’s upper atmosphere.
The advantage of high altitude is that the Cerenkov radiation due to gamma-rays which normally occurs at 10 km altitude above sea level, will be at 5.5 km above ground, almost half the distance from the telescope. The intensity of radiation on the ground will be four times higher. A smaller facility in such place will be sufficient to achieve what a bigger facility will do closer to sea level.
