ionizing photons tagged posts

The Cosmic Horseshoe, as photographed by the Hubble Space Telescope. Credit: ESA/Hubble & NASA

Astronomers use observations of gravitationally lensed galaxy to measure properties of early universe. Although the universe started out with a bang it quickly evolved to a relatively cool, dark place. After a few hundred thousand years the lights came back on and scientists are still trying to figure out why. Astronomers know that reionization made the universe transparent by allowing light from distant galaxies to travel almost freely through the cosmos to reach us. However, astronomers don’t fully understand the escape rate of ionizing photons from early galaxies...

This is a Hubble Space Telescope image of the compact green pea galaxy J0925+1403. The diameter of the galaxy is approximately 6,000 light years, and it is about twenty times smaller than the Milky Way. Credit: NASA

Astronomers gain a new understanding of the re-ionization of the universe by studying a nearby dwarf ‘green pea’ galaxy. Newly formed dwarf galaxies were likely the reason that the universe heated up about 13 billion years ago. The finding opens an avenue for better understanding the early period of the universe’s 14 billion year history.

In the period of several hundred thousand yrs after the Big Bang, the universe was so hot and dense that matter was ionized instead of being in a neutral form...