The Major Atmospheric Cherenkov Experiment Telescope (MACE) is one of the world’s largest gamma-ray telescopes, designed to study high-energy cosmic gamma-ray sources. Read here to learn more.
Located near Leh in Hanle, Ladakh, India, at an altitude of about 4,300 meters, MACE detects Cherenkov radiation, which is emitted when gamma rays interact with the Earth’s atmosphere.
The Department of Atomic Energy has installed (on 4th October 2024) the Major Atmospheric Cherenkov Experiment (MACE) Observatory in Ladakh.
MACE telescope will observe high-energy gamma rays such as supernovae, black holes, and gamma-ray bursts.
This newly installed facility will complement global observatories and is an important feature in strengthening India’s position in the field of multi-messenger astronomy.
Major Atmospheric Cherenkov Experiment (MACE) Observatory
MACE, which is installed at Hanley in eastern Ladakh is considered the largest imaging Cherenkov telescope in Asia as well as the highest in the world for being installed at an altitude of 4,300 metres.
It is indigenously built by Baba Atomic Research Centre with support from the Electronic Corporation of India and other Indian industry partners.
Key Features of MACE:
- Cherenkov Detection Mechanism: MACE observes Cherenkov radiation produced when high-energy gamma rays from cosmic sources enter the Earth’s atmosphere, generating particle showers. These particle interactions emit Cherenkov light, which the telescope collects and analyzes.
- Scientific Objectives:
- Study of Gamma-ray Sources: MACE helps investigate gamma-ray sources such as supernova remnants, pulsars, and active galactic nuclei. These sources are critical in understanding high-energy astrophysical processes.
- Understanding Cosmic Ray Origins: By studying gamma rays, MACE contributes to the study of cosmic rays’ origins and their propagation through the universe.
- Dark Matter Research: The telescope also plays a role in probing potential signals related to dark matter and other exotic phenomena.
Technological Advances
MACE boasts a large mirror of 21 meters in diameter, making it one of the largest telescopes of its kind, enhancing its sensitivity to high-energy gamma rays.
Its location in the high-altitude, dry region of Ladakh ensures minimal atmospheric interference, crucial for accurate Cherenkov radiation detection.
- The MACE Telescope consists of a large-area tessellated light collector of 356 m², made up of 356 mirror panels.
- A high-resolution imaging camera weighing about 1200 kg, for detection and characterization of the atmospheric Cherenkov events, forms the focal plane instrumentation of the telescope.
- The elevation over azimuth mounted telescope basket structure has two axes movement capability of ± 270° in azimuth and -26° to +165° in elevation for pointing towards any source in the sky and tracking it.
- The telescope, which weighs about 180 tons, is supported on six wheels that move on a 27-metre-diameter track.
- The telescope has an integrated imaging camera, which contains 1088 photo multiplier-based pixels and all the signal processing and data acquisition electronics.
- The camera communicates the acquired data to the computer system in the control room over optical fibre.
Significance of MACE
- The MACE telescope is expected to play a very important role in studying the sources of cosmic gamma radiation like Active Galactic Nuclei (AGNs), Gamma Ray Bursts (GRBs), Pulsars, Binary Star Systems, Remnants of Supernova explosions (SNR), Giant Molecular Clouds (GMC), Star Burst Galaxies and other objects in our Milky-Way Galaxy through observations of gamma rays with energies above 20 GeV.
- Beyond probing the non-thermal Universe and cosmic accelerators, the MACE telescope is also expected to address a range of cosmological topics such as constraining the intensity of Extragalactic Background Light (EBL) and strength of Intergalactic Magnetic Field (IGMF), cosmic ray electron spectrum, search for Dark Matter (DM) particles.
- MACE will also probe some fundamental physics problems like Lorentz Invariance Violation (LIV), anomaly in photon-photon pair production and photon-Axion Particle (ALP) oscillations.
The fundamental questions that can be addressed using the MACE telescope
- Origin of cosmic rays, i.e. how cosmic rays are energized and where?
- Characterize the extra-galactic background light (EBL). This has immense importance in understanding the evolution of the Universe.
- Detection of dark matter through gamma rays produced in the decay or annihilation of dark matter.
- Signatures of quantum gravity by measuring the time delay between two photons of the highest energies.
International Collaboration
MACE is part of India’s broader initiative in high-energy astrophysics, and it works in conjunction with other international gamma-ray observatories, contributing to global astrophysical research efforts.
Cosmic rays
Cosmic rays were discovered by Victor Hess in 1912. Even after one hundred years of their discovery, it is not known how and where cosmic rays are originated.
- Some hints indicate that Supernova Remnants (SNR), Pulsar Wind Nebulae (PWN), Active Galactic Nuclei (AGNs) etc., are the possible sites where cosmic rays can be produced.
- As cosmic rays are charged particles they get deflected in interstellar and intergalactic magnetic fields therefore from the direct detection of cosmic-ray particles on the Earth one can’t trace back to their site of origin. However, an alternative path was suggested by astrophysicists.
- Cosmic rays can interact with the ambient medium at the site of their origin and can produce gamma rays.
- This gamma ray can reach the Earth without any deviation in its path.
- Therefore, if one can detect such gamma rays from the astrophysical sources then one can trace back their origin.
- In fact in the early 80’s the first gamma-ray satellite Cos-B sent by NASA detected 25 sources in million electronvolts (MeV, 1 MeV = 106 eV) energy range.
- This detection gave birth to gamma-ray astronomy and it became the most favorable path to study cosmic-ray origin.
- With time the field of gamma-ray astronomy evolved a more sensitive technique called the Imaging Atmospheric Cherenkov Technique (IACT), which works in the giga electronvolt (GeV, 1 GeV = 109 eV) to tera electronvolt (TeV, 1 TeV = 1012 eV) energy range.
In India, the first IACT telescope TACTIC (TeV Atmospheric Cherenkov Telescope with Imaging Camera) started operating in the year 1997 at Mount Abu, Rajasthan.
- Now a more sensitive telescope the MACE is installed at Hanle to study the gamma-ray sky in the energy range 20 GeV – 10 TeV.
- The higher photon density along with the low background light level at this site helps in lowering the energy threshold of the Cherenkov telescope.
Conclusion
MACE enhances India’s contribution to gamma-ray astronomy and helps place it among the global leaders in astrophysical research, adding to the understanding of cosmic phenomena like black holes, neutron stars, and dark matter.
One can study different types of astrophysical sources with the MACE telescope such as supernova remnants, pulsar wind nebula, active galactic nuclei, gamma-ray bursts, pulsars, starburst galaxies, gamma-ray binary and dark matter.
Frequently Asked Questions (FAQs)
Q. Which is the largest telescope in Asia Ladakh?
Ans: Ladakh now hosts the Major Atmospheric Cherenkov Experiment observatory, the world’s highest imaging Cherenkov telescope, inaugurated by Dr Ajit Kumar Mohanty. Built by BARC with Indian partners, MACE is Asia’s largest telescope.
Q. Where is India’s largest telescope?
Ans: The 3.6m Devasthal Optical Telescope is a custom-built instrument of great complexity. This telescope has the distinction of being the largest telescope in India for the study of celestial objects at optical wavelengths. It is a national facility installed at Devasthal in the district of Nainital, India.
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-Article by Swathi Satish
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