Washington, November 1: Dark galaxies – galaxies with few if any stars and made predominately of dense gas – have been impossible to detect directly- until now.
An international team of astronomers, using the European Southern Observatory’s 8.2-meter Very Large Telescope (VLT) in Chile, has now detected several dark galaxies by observing the fluorescent glow of their hydrogen gas illuminated by the ultraviolet light of a nearby quasar.
The galaxies detected by the team are nearly 11 billion light years away, which means they existed at an early time in the 13.7 billion-year-old Universe.
Dark galaxies are thought to be the building blocks of modern-day star-forming galaxies, either through mergers with star-forming galaxies, or by feeding them gas along filaments that connect the Universe’s galaxies in a kind of cosmic web.
Three members of the team that made the detection spoke recently with The Kavli Foundation in a roundtable discussion about how they made the discovery, what it means, what questions are still unanswered, and what they plan next.
They are Sebastiano Cantalupo – Postdoctoral Fellow at the University of California, Santa Cruz, the Astronomy and Astrophysics Department, Martin Haehnelt – Professor of Cosmology and Astrophysics, Institute of Astronomy and the Kavli Institute for Cosmology, University of Cambridge and Simon Lilly – Professor of Observational Cosmology, Institute for Astronomy at the Swiss Federal Institute of Technology in Zurich, Switzerland. (ANI)