Galaxies' Spiral Arms Helped Create Stars in the Early Universe

Topic: Space

Astronomers have discovered that spiral arms and bars in galaxies helped create stars at a faster rate than today. This was during a time called cosmic noon, about 2-3 billion years after the Big Bang.

Peak star formation took place during cosmic noon, between 2–3 billion years after the Big Bang. The star formation rate (SFR) back then was up to 100 times greater than it is today.

Astronomers have struggled with this fact because early galaxies were thought to be messy and chaotic due to mergers and turbulence. But new research reveals something different. It shows that massive disk galaxies with bars and spiral arms moved cold gas around efficiently, driving their high SFRs.

Stars can form only from cold gas. If gas is heated by something like an active galactic nucleus or is turbulent because of a merger, then star formation suffers. Only cold, dense gas can collapse to form stars. Inside galaxies, this means that cold gas has to flow from the outer disk into the central regions, where stars form.

The two new papers are based on NOEMA3D, a survey of how cold gas moves around in star-forming galaxies during cosmic noon. NOEMA3D examined massive main-sequence galaxies with JWST and NOEMA, the Northern Extended Millimeter Array, to generate a high-resolution study of molecular gas kinematics.

Why It Matters

This discovery helps us understand how stars were formed in the early universe, which is important for understanding our own galaxy's history and evolution. It also shows that galaxies can be more organized and efficient than we thought, which has implications for our understanding of galaxy evolution.

Key Facts

• Peak star formation took place during cosmic noon, between 2–3 billion years after the Big Bang.
• The star formation rate (SFR) back then was up to 100 times greater than it is today.
• Massive disk galaxies with bars and spiral arms moved cold gas around efficiently, driving their high SFRs.
• NOEMA3D is a survey of how cold gas moves around in star-forming galaxies during cosmic noon.
• The research is based on observations from JWST (James Webb Space Telescope) and NOEMA (Northern Extended Millimeter Array).

Key Terms

SFR

Star formation rate, which measures how many stars are formed in a given time period.

Cosmic noon

A time about 2-3 billion years after the Big Bang when star formation was at its peak.

NOEMA3D

A survey of how cold gas moves around in star-forming galaxies during cosmic noon.

Implications

This discovery helps us understand how stars were formed in the early universe, which is important for understanding our own galaxy's history and evolution. It also shows that galaxies can be more organized and efficient than we thought, which has implications for our understanding of galaxy evolution.