Canadian Hydrogen Intensity Mapping Experiment

It is a radio telescope designed to answer the major questions of cosmos and astronomy. It would also facilitate in knowing the mysteries of our universe.

Where is it located?

The CHIME telescope is located at the Dominion Radio AstrophysicalObservatory, a national facility for astronomy operated bythe National Research Council of Canada.

Why in news?

Scientists from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) have detected 535 Fast Radio Bursts (FRB). It is the largest collection of FRB till date.

Collaborating institutions

The project is co-led by –

  • TheUniversity of British Columbia
  • McGill University
  • University of Toronto
  • Tata Institute of Fundamental Research
  • National Centre for Radio Astrophysics(NCRA)

Working of telescope

  • The CHIME is a novel radio telescope and has no moving parts. It was originally conceived to map the most abundant element in the universehydrogen– over a good fraction of observable universe.
  • This telescope is optimized to have a high “mapping speed”, which requires a large instantaneous field of view(~200 square degrees) and broad frequency

coverage.

  • The digitized signals collected by CHIME will be processed to form a 3-dimensional map of hydrogen density, which will be used to measure the expansion history of the universe.
  • The CHIME telescope comprises four massive parabolic radio antennasand it receives radio signals each day from half of the sky as the Earth rotates.
  • It has a powerful digital signaling processor that works at about seven terabits per second – equivalent to a few percent of the world’s internet traffic.
  • The digital signal processor reconstructs and looks in thousands of directions simultaneously.This helps in detecting Fast Radio Bursts(FRBs)thousand times more often than the traditional telescope.

Significance of this experiment

CHIME will map the history of the expansion rate of the Universe by observing hydrogen gas in distant galaxies that were very strongly affected by Dark Energy. The experiment will measure the relic of Baryon Acoustic Oscillations(BAO), spherical shells of matter over-density in which galaxies and gas are more likely to be found today. What this means is that, for the past 13 billion years, this characteristic distance scale evolved solely due to the expansion of the Universe, and hence provides a standard ruler to measure the expansion rate.

It would also help in understanding the Expanding Universe Hypothesis given by Edwin Hubble. Also, it will shed light on understanding the working of dark energy and its role in cosmos.

FAST RADIO BURSTS(FRBs)

What are they?

Fast radio bursts are intense bursts of radio emission that have durations ofmilliseconds and exhibit the characteristic dispersion sweep of radio pulsars.

When was it first discovered?

They were discovered in 2007 by American astronomer Duncan Lorimer led to the term ‘Lorimer Bursts’. Since then just a few dozen similar events have been observed in data collected by radio telescopes around the world, building evidence that points to a variety of potential causes.

What is the source of Fast Radio Bursts?

Source of FRBs could be Magnetars.

What is a Magnetar?

As per NASA, a magnetar is a neutron star, “the crushed, city-size remains of a star many times more massive than our Sun.” The magnetic field of such a star is very powerful, which can be over 10 trillion times stronger than a refrigerator magnet and up to a thousand times stronger than a typical neutron star’s.

What is a Neutron star?

Neutron stars are formed when the core of a massive star undergoes gravitationalcollapse when it reaches the end of its life. This results in thematter being so tightly packed that even a sugar-cube sized amount of material taken from such a star weighs more than 1 billion tons, which is about the same as the weight of Mount Everest, according to NASA.

Magnetars are a subclass of these neutrons and sometimes release flares withmore energy in a fraction of a second than the Sun is capable of emitting in tens of thousands of years.

Newly discovered Fast Radio Bursts

Discovered by the CHIME experiment.

Location of FRBs

When the scientists mapped their locations, they found the FRBs were evenly distributed in space, seeming to arise from any and all parts of the sky.

What are the types of FRBs detected?

They fall in two distinct classes

  • Those which repeat
  • Those that didn’t repeat

The repeater FRBs looked different. Each burst lasted slightly longer and emitted more focused radio frequencies than bursts from non-repeating FRBs.

The differences suggest that emission from repeaters and non-repeaters is either generated by different astrophysical mechanisms or in different astrophysical environments.

What is the significance of Fast Radio Bursts and their detection?

  • To study the cosmos- Fast radio bursts can be used to study the three–dimensional structure of matter in the universe.
  • Some theorists believe that the most distant bursts could be used to learn about poorly understood early moments in the evolution of the universe.
  • Astronomers are also of the opinion that such FRB events could be used to map out the structure of the universe.
  • The detection would also help in realizing the full potential of such experiments and pave a way for new technological interventions inspace research and development.

What lies ahead?

CHIME and other telescopes are detecting more fast radio bursts every day, but researchers are just scratching the surface of what can be learned about – and done with – these mysterious and powerful cosmic events.

Finding host galaxies is very challenging, though – only 14 galaxies that host fastradio bursts have been found so far. But other telescopes, like the AustralianSquare KilometreArray Pathfinder, have successfully detected and pinpointed a small number of nonrepeating bursts to their host galaxies. Next-generationtelescopes are being designed to combine the high-detection capability of CHIME with the high-resolution imaging of the Australian telescope.

Canadian Hydrogen Intensity Mapping Experiment

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