It's Cosmic Dawn! When Stars Were Formed 250 Million to 350 Million Years After Beginning of Universe

A new study led by University College London and the University of Cambridge researchers specified that cosmic dawn, when, for the first time, stars formed, took place 250 million to 350 million years following the beginning of the universe.

According to a SciTechDaily report, the study suggests that the NASA James Webb Space Telescope, scheduled for launch in November, "will be sensitive enough" to directly observe the birth of galaxies.

The UK-led research team investigated six of the most distant galaxies presently known, whose light has taken the majority of the lifetime of the universe to reach us.

They discovered that the galaxies' distance, away from this planet, to "lookback time" of over 13 billion years ago, when the age of the universe was only 550 million years old.

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Galaxies' Age Calculated

Researchers of the study, "Probing cosmic dawn: Ages and star formation histories of candidate z ≥ 9 galaxies", published in the Monthly Notices of the Royal Astronomical Society, analyzed images from the Hubble and Spitzer Space Telescopes.

Using the device, the study authors calculated these galaxies' age as ranging from 200 to 300 million years, enabling an estimate of when their stars initially formed.

According to University of Cambridge's Dr. Nicolas Laporte, the study's lead author who started the project while at UCL, theorists are speculating that the universe "was a dark place for the first few hundred million years," prior to the formation of the first stars and galaxies.

Witnessing the moment, explained Laporte, when the universe was initially bathed in starlight, is a major mission in the field of astronomy.

He added, their observations specify that cosmic dawn took place between 250 million and 350 million years following the beginning of the universe, and during the time of their formation, galaxies like the ones the researchers studied would have been adequately luminous to be observed with the JWST.

Starlight Analyzed

Essentially, the study investigators analyzed starlight from the galaxies as the Hubble and Spitzer Space Telescope recorded, studying a marker in their distribution of energy suggestive of the atomic hydrogen's presence in their stellar atmosphere. This provides an approximate of the age of stars they comprise.

The hydrogen signature increases in strength as the cosmological population ages although diminishes when the galaxy is older than one billion years.

The age-reliance arises since the more massive stars that add to the signal are burning their nuclear fuel faster and thus, die first.

The age indicator, explained co-author Dr. Romain, from the UCL Physics & Astronomy and the Max Planck Institute for Astronomy in Heidelberg, Germany, is used to date stars in the Milky Way although it can be used as well, to date tremendously remote galaxies, observed at such an early period of the universe.

Using such an indicator, the co-author added, they can infer that even in the early times, the galaxies are aged from 200 million to 300 million years old.

'Redshift'

In a similar report, University of California news specified, in examining the data from Hubble and Spitzer, the study authors needed to approximate each galaxy's so-called "redshift" which specifies their cosmological distance and therefore, the lookback time of their observation.

To achieve this, they carried out spectroscopic measurements through the use of the full armory of powerful ground-based telescopes, specifically the Chilean Atacama Large Millimetre Array or ALMA, Gemini-South telescope, European Very Large Telescope, and the twin Keck Telescopes in Hawaii.

Such measurements allowed the team to verify that looking at these galaxies corresponded to looking back to when the universe's age was 550 million years old.

Related information about stars' formation is shown on Launch Pad Astronomy's YouTube video below: