This artist's conception shows the dust continuum, molecular lines and molecular structures of carbon monoxide (and water) seen in the pair known as SPT0311 and 58. ALMA data shows that there is abundant CO and H20 within the larger of these two galaxies. This indicates that the molecular Universe was still strong just a few years after the elements were first forged. Credit: ALMA (ESO/NAOJ/NRAO)./S. Dagnello (NRAO)
Water has been detected in the most massive galaxy in the early universe, according to new observations from the Atacama Large Millimeter/submillimeter Array (ALMA). Scientists who studied SPT031158 discovered H20 and carbon monoxide in this galaxy that is nearly 12.88 billion years from Earth. These two molecules were found in high numbers in the galaxy, which is located close to 12.88 billion light years from Earth. This suggests that the molecular universe was still strong just after the elements were formed in early stars. This new research includes the most comprehensive study to date of the molecular gas composition of a galaxy in early universe. It also contains the first detection of H20 in regular star-forming galaxies. The Astrophysical Journal published the research.
SPT031158 actually consists of two galaxies and was first spotted by ALMA scientists in 2017. Its location or time in the Epoch for Reionization is where it was first seen. The universe was only 780 million years old, or about 5-percent of its present age. This was also when the first stars and galaxies were born. Scientists think that the galaxies are merging and that their star-forming speed is not only consuming their gas but may also be transforming them into massive elliptical galaxyes, like those found in the Local universe.
"Using high-resolution ALMA observations, we found both water molecules and carbon monoxide molecules within the larger of two galaxies. Sreevani Jarugula is an astronomer at University of Illinois who was the principal investigator of the new research. This galaxy is the largest known galaxy at high redshift. It was formed when the universe was very young. It is more dense than other galaxies of the early universe. This gives us lots of opportunities to observe abundant molecules, and better understand how these life-creating elements affected the development of our universe.
These science images depict the molecular and dust continuums seen in ALMA observations of SPT0311-58, the pair of young massive galaxies. Left: A composite image that combines the dust continuum and molecular lines H20 and CO. Credit: ALMA/ESO/NAOJ/NRAO/S. Dagnello (NRAO)
This animated gif shows the dust continuum, as well as the molecular lines for carbon monoxide and water seen in ALMA observations. It is based on ALMA observations of two early massive galaxies called SPT0311-58. The gif starts with a composite of the dust continuum and molecular lines H20/CO. The dust continuum is shown in red, the molecular line for H20 in blue, and molecular links for carbon monoxide. CO(10-9) shown in pinks, deep blue, and CO(7) shown in magenta. CO(6) shown in purple. Credit: ALMA (ESO/NAOJ/NRAO)./S. Dagnello (NRAO)
Particularly water is the third most abundant molecule after carbon monoxide and molecular hydrogen in the universe. Studies of galaxies from the early and local universes have previously shown a correlation between water emission and far-infrared emissions from dust. Jarugula stated that dust absorbs ultraviolet radiation from stars in the galaxy, and then re-emits it to form far-infrared photosns. This further excites the water molecules and gives rise to the water emissions that scientists can observe. It allowed us to detect water emissions in the massive galaxy. This could be used to identify star formation and then applied to galaxies at a cosmological level.
Scientists can learn more about the evolution and birth of the universe by studying the formation of the first galaxies in the universe. Jarugula stated that early galaxies are creating stars at a rate many times greater than the Milky Way. "Studying the dust and gas content in these early galaxies gives us information about their properties such as how many stars are formed, the rate at gas conversion into stars, how galaxies interact and how interstellar medium works, and much more."
Jarugula says there is still much to be learned about SPT031158 and the galaxies in the early universe. This study provides information about water's location in the universe. It also raises a major question: How did so much gas and dust combine to form galaxies and stars so early in the universe's history? To find out the structure and evolution of early universe, we need to study these galaxies and others like them.
Joe Pesce (astrophysicist, and ALMA Program Director at The National Science Foundation) said, "This exciting result which shows the power ALMA adds to an increasing collection of observations of early universe,". These molecules are vital to life on Earth and their observation gives us insight into fundamental processes in a universe that is very different from ours.
More information: "Molecular Line Observations In Two Dusty Star-Forming Galaxies at z = 6.9," S. Jarugula et. al. 2021. The Astrophysical Journal, preprint: arXiv.2108.11319v1 (astro-ph.GA), Journal information: Astrophysical Journal: "Molecular Line Observations In Two Dusty Star Forming Galaxies at z= 6.9," S. Jarugula et.al. 2021 The, pre-print: arXiv:2108.11319v1 [astro-ph.GA], arxiv.org/abs/2108.11319
