As part of the CRISTAL (CII Resolved ISM in STar-forming galaxies with ALMA) survey, astronomers peered back to when the Universe was only about one billion years old.
This artist’s impression of the formation of a galaxy in the early Universe featuring clumps of star-forming galaxies, with carbon gas shown in red, and dark dust shown in black. This process is documented in detail throughout the many galaxies observed in ALMA’s CRISTAL survey. Image credit: NSF / AUI / NRAO / B. Saxton.
“ALMA’s incredible ability to see through dust and gas has allowed us to observe these distant galaxies in remarkable detail,” said Dr. Rodrigo Ignacio Herrera Camus, an astronomer at the Universidad de Concepción.
“We’re not just seeing blobs of light; we’re resolving the internal structures of these galaxies and learning about the processes happening within them.”
In the CRISTAL survey, the astronomers focused on a sample of star-forming galaxies that showed the typical relationship between a galaxy’s mass and its star formation rate.
The ALMA observations revealed that some galaxies showed signs of orderly rotation, suggesting the formation of early disks. Others displayed chaotic motions and disturbed shapes, indicative of galaxies colliding and merging.
ALMA also detected clouds of gas, revealed by their emission of a specific type of light from ionized carbon, extending far beyond the regions where stars formed. This suggested that galaxies are surrounded by vast gas reservoirs, potentially fueling future star formation or being expelled by powerful outflows.
Many galaxies exhibited star formation occurring in distinct clumps, providing insights into how stars are born in these early systems.
The family portrait of early galaxy formation created from the research of the CRISTAL survey. Image credit: CRISTAL Large Program.
One particularly intriguing finding is the discovery of an early galaxy named CRISTAL-10.
This galaxy exhibits an extreme deficit of ionized carbon emission relative to its far-infrared light, a ratio similar to that seen in Arp 220, one of the most luminous and obscured galaxies in the local Universe.
Further study of this galaxy could reveal the interstellar medium’s power source and physical state in the early Universe.
“CRISTAL provides the kind of detailed data that simply wasn’t possible before ALMA,” Dr. Herrera Camus said.
“We’ve got a new family portrait of early galaxy evolution.”
“These observations are challenging our existing models of galaxy formation and providing new avenues for research.”
“The CRISTAL survey demonstrates the power of ALMA for studying galaxy evolution in the early Universe.”
“By tracing the cold gas and dust that fuel star formation, ALMA is helping scientists piece together the story of how galaxies like our own Milky Way came to be.”