Italian astronomy enthusiasts Giuseppe Donatello He discovered a previously unknown dwarf galaxy in the outskirts of the giant Andromeda galaxy. Likely a mysterious fossil of the first galaxies.
Andromeda is the closest large galaxy to our Milky Way. It is a spiral galaxy roughly twice the size.
The new dwarf galaxy — seen as a smudge in old data from the 4-meter Victor M Blanco Telescope at Cerro Tololo International Observatory in Chile — is called Pegasus V. The Gemini Northern Telescope in Hawaii.
Pegasus V contains very few heavier elements, which means its stars are very old, hence its classification as a fossil of the first galaxies.
Michelle Collins, an astronomer at the University of Surrey in the UK and lead author of paper Announcing the discovery in Monthly Notices of the Royal Astronomical Society.
Why is it mysterious? Dim monumental galaxies like Pegasus V should be everywhere. Since they are remnants of the first galaxies that formed the universe, they are teeming with them.
It’s not – that means astronomers’ understanding of cosmology and dark matter may be wrong.
Fossil galaxies like Pegasus V are not easy to find. Even through a large telescope they look like a smudge from some very old stars. “They have very few bright stars that we normally use to identify and measure their distances,” said Emily Charles, a doctoral student at the University of Surrey who was also involved in the study. “Gemini’s 8.1-meter mirror allowed us to find faint old stars, enabling us to measure the distance to Pegasus V and determine that the number of stars there is very old.”
This galaxy fossil from the early universe may help astronomers understand how galaxies formed and whether theories about dark matter are correct.
Next is the James Webb Space Telescope, which will soon see the “first light” and begin the search for the first galaxies.
I wish you a clear sky and wide eyes.