Einstein Cross reveals young galaxy with surprisingly old stars

Astronomers used a rare Einstein Cross gravitational lens to study elliptical galaxy J1453g as it appeared about 8 billion years ago and found its central stars have compositions similar to the Milky Way. The research was published April 2 in Nature Astronomy.

Astronomers have used a rare Einstein Cross gravitational lens to study the elliptical galaxy J1453g as it appeared about 8 billion years ago. The lensing magnified and produced multiple images of a more distant quasar, allowing detailed measurements. That geometry let the team determine the mass distribution of stars in J1453g with unusual precision. The measurements show the galaxy's central stars have compositions similar to those in the Milky Way, which surprised the researchers and bears on models of galaxy formation and evolution. Key facts: - J1453g is an elliptical galaxy observed as it was around 8 billion years ago, when the universe was less than 6 billion years old. - J1453g acts as a gravitational lens that produces an Einstein Cross by magnifying light from a background quasar powered by a supermassive black hole. - The lens geometry enabled the team to measure the mass distribution of stars in the galaxy's centre with unprecedented precision. - The central stars' composition closely resembles that of the Milky Way despite the galaxy's youth. - The team's results were published April 2 in the journal Nature Astronomy. Summary: The findings suggest some massive galaxies in the early universe may have central stellar populations similar to those in mature galaxies, which could complicate existing models of galaxy formation. The observation provides a new empirical constraint for theoretical work and model development. Undetermined at this time.