Enlarge / Artist’s impression of a progenitor of galaxies like the Milky Way, seen when the Universe was only 1.5 billion years old. New observations reveal that these galaxies are surrounded by massive halos of hydrogen gas. (credit: A. Angelich (NRAO/AUI/NSF))
The early Universe can be studied by looking at light coming from distant galaxies. The farther away the galaxy is, the longer its light takes to reach us, so we can see extremely distant galaxies as they were billions of years ago. However, the further back in time we look through this method, the more difficult it becomes to clearly resolve any features about the galaxies we’re looking at.
An easier task, and one researchers have been doing for decades, is to study the gas surrounding early galaxies. When light passes through this gas, certain wavelengths of light are absorbed, while others aren’t. The result is that there are certain gaps, or lines, in this light. But until now, that’s as far as researchers could go for the most part: they couldn’t learn much about the galaxies themselves.
In a new study, researchers have directly imaged two Milky Way-like galaxies through observations from ALMA (the Atacama Large Millimeter/submillimeter Array). The galaxies seem to have the properties of massive, star-forming galaxies.
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Source: Ars Technica – Millimeter telescope array spots early galaxies in “super halos” of gas