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Space Telescopes Find Hidden Cosmic Factories

Scientists reveal a universe buzzing with extreme energy. New observations are uncovering more sources of very high energy gamma-rays, linking them to cosmic ray origins.

The Hunt for Cosmic Rays

Researchers reviewed studies presented at a major cosmic-ray conference. They focused on ground-based telescopes that scan the sky for powerful gamma-rays. These rays are like tiny, super-fast bullets from space.

The team looked at data from telescopes like:

  • VERITAS
  • MAGIC
  • H.E.S.S.
  • FACT
  • HAWC

These instruments use different tricks to catch gamma-rays. Some, like Imaging Atmospheric Cherenkov Telescopes [IACTs], see fleeting flashes of light. Others, like air shower arrays, catch the actual tiny particles produced when gamma-rays hit Earth’s atmosphere. Think of it like seeing a lightning strike versus feeling the thunder.

Expanding the Map of Extreme Cosmic Events

The review found 198 known very high energy gamma-ray sources by mid-2017. HAWC alone recently found 39 of these sources, with 19 being brand new. This significantly expands our map of extreme cosmic events.

"After more than ten years of observations with the current generation’s IACTs, we are still finding large numbers of new VHE gamma-ray sources in the sky."

What are these Gamma-Ray Factories?

These cosmic factories include:

  • Exploding stars: known as supernova remnants.
  • Spinning neutron stars: called pulsar wind nebulae.
  • Supermassive black holes: located at the heart of faraway galaxies, known as active galactic nuclei.

Observing these helps scientists understand how cosmic rays — high-energy particles constantly bombarding Earth — are made.

The Future of Gamma-Ray Astronomy

However, some gamma-ray sources remain a mystery, as current telescopes have limits on what they can see clearly.

Upcoming projects, like the Cherenkov Telescope Array [CTA], promise sharper views and will likely reveal even more secrets of the gamma-ray universe. These discoveries continue to shed light on some of the universe's most powerful events.

Reference: Nahee Park, "Status of ground based gamma-ray observations," arXiv:1808.10495v1 [astro-ph.HE] 30 Aug 2018.