The World’s Largest Telescope at the Highest Altitude – MACE
Major Atmospheric
Cerenkov Experiment Telescope or MACE Hanle, is the world's largest
telescope at the highest altitude being established at Hanle, Ladakh. It
is being built by ECIL, Hyderabad for BARC. It will be built in Hyderabad and
will be assembled at the campus of Indian Astronomical Observatory at Hanle. It
will be remotely operated and will run on Solar Power.
It will help to explore
the exciting energy range of gamma ray energy region in between satellite and
the traditional Atmospheric Cerenkov experiments. The telescope is named after
the Russian scientist Cerenkov who predicted that charged particles moving at
high speeds in a medium, emit light.
According to Dr Tushar P Prabhu,
Professor in-charge at Hanle, Indian Institute of Astrophysics, Bangalore will
conduct experiments. IIA in collaboration with Tata Fundamental Research
Institute (TIFR), demonstrated the advantages of high altitude by installing
High Altitude Energy Gamma Ray (HAGAR) Telescope.
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.
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.
The advantage of high
altitude is that the Cerenkov radiation due to gamma-rayswhich 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. Telescopes of
HAGAR were fabricated in Bangalore and the detectors in the focal plane were
built in TFIR laboratories at Mumbai. In 2008 HAGAR saw the first light, and
observations are continuing thereafter.
One of the important
observations was of a galaxy with an active nucleus where the activity
increases occasionally due to processes in matter falling on the black hole.
The Himalayan Chandra
Telescope (HCT) at Hanle, has discovered three galaxies with super
massive black holes out of observation of 10 galaxies. The other important
discoveries of the telescope include subtle differences between different
supernovae explosions and new variable stars forming in our galaxy. The HCT
also successfully discovered a number of low metallicity stars.
The 2-m aperture
optical-infrared telescope, HCT, was installed in 2000 and started
its operation remotely since 2001.The telescope is equipped
with 3 science instruments which are mounted on an instrument cube at the cassegrain focus
of the telescope. The instruments available are the Himalayan Faint Object
Spectrograph (HFOSC), the near-IR image, and the optical CCD imager. The remote
operations make easy for astronomers to work without travelling to the remote
high altitude site. Astronomers from all over the world and from other
countries are using this.
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