The first stars formed after 400 million years after the birth of our universe. A new light-filled era began after the dark ages ended. The process of making new stars took about 4 billion years after the Bigbang.
This time period can be observed by astronomer. Our universe is more than 13 billion years old and our telescopes can pick up light from the past. Most of the stars being formed are hidden by dust, so the details of this chapter in our universe's history are not clear.
The COMAP project will help answer questions about what caused the universe's rapid increase in the number of stars.
The project's principal investigator and the associate director of Caltech's Owens Valley Radio Observatory says that most instruments might see the tip of an iceberg. COMAP will be able to see what's hidden.
The current phase of the project uses a radio dish at OVRO to study the most common kinds of star-forming galaxies spread across space and time, including those that are too faint or hidden by dust. Cold hydrogen gas is traced by the radio observations. COMAP uses bright radio signals from carbon monoxide gas, which is always present along with the hydrogen, to measure this gas. The most powerful radio camera is built by COMAP.
Seven papers from the project have just been published in The Astrophysical Journal. COMAP set upper limits on the amount of cold gas that can be seen, including the ones that are too faint and dusty to see. The project has not yet made a direct detection of the CO signal, but the early results show that it is on track to do so by the end of the initial five year survey.
The technique will be used to look further and further back in time. We will push back time until we reach the first stars and galaxies a couple of billion years earlier.
Anthony Readhead is the co-principal investigator and the Robinson Professor of Astronomy. He says that they will watch star formation rise and fall like an ocean tide.
COMAP uses radio waves to capture blurry images of clusters of galaxies over time. This blurriness makes it possible for the astronomer to efficiently catch all the radio light coming from a larger pool of galaxies.
In this way, we can find the average properties of faint galaxies without knowing where they are located. It's like finding the temperature of a large volume of water using a thermometer, instead of analyzing the motions of the individual water molecule.
There is a summary in the Astrophysical Journal.
More information: Kieran A. Cleary et al, COMAP Early Science. I. Overview, The Astrophysical Journal (2022). DOI: 10.3847/1538-4357/ac63cc Journal information: Astrophysical Journal
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