Atacama Large Millimeter/submillimeter Array (ALMA) Telescope

Why in News?

Recently, astronomers have released the largest-ever ALMA image of the Milky Way’s central region under the ACES – ALMA Central Molecular Zone Exploration Survey.

• Location – It is located in the Atacama Desert, Chile.
• Located at an altitude of about 5,000 metres on the Chajnantor Plateau.
• The location is ideal for radio astronomy due to high altitude and extremely dry conditions.
• Purpose – Formation of stars and planets, Molecular clouds and protoplanetary disks, Early galaxies in the universe and Chemical composition of space.
• Operational Since – 2013.
• Collaboration – ALMA is a joint international venture–
  • Led by European Southern Observatory (Europe)
  • U.S. National Science Foundation (NSF)
  • National Institutes of Natural Sciences (Japan)
  • In cooperation with the Republic of Chile
• Core Specifications - It is not a single telescope but an interferometer—a network of 66 high-precision antennas that work together as one giant instrument.

• Technique - It uses a technique called interferometry. By combining the signals from multiple antennas, it mimics a single telescope with a diameter equal to the distance between the furthest antennas.

Key Findings Using ALMA

• Largest-Ever High-Resolution Map – First time the entire Central Molecular Zone (CMZ) has been mapped in such detail.
• Area Covered – Over 650 light-years across the CMZ.
• Size – Mosaic equivalent to 3 full Moons side-by-side in sky coverage.
• Discovery of Filamentary Gas Network – Long, thin streams of cold molecular gas detected.
• Gas flows along filaments feeding star-forming regions.
• Reveals how matter moves toward dense star-forming clumps.
• Hidden Astrochemistry Uncovered – Detection of dozens of molecules, including –
  • Simple molecules – Silicon monoxide (SiO)
  • Complex organic molecules – Methanol, Ethanol, Acetone.
• Indicates rich chemical complexity in extreme environments.
• Star Formation Paradox – Despite having very high gas density, the CMZ of the Milky Way forms stars at a much lower rate than predicted by standard star-formation models.

References

1. The Guardian | ALMA Telescope
2. ESO | Largest image of the heart of the Milky Way