Astronomers have utilized spectral data from the Hobby-Eberly Telescope at McDonald Observatory to construct the most intricate 3D map of faint cosmic structures dating back 9 to 11 billion years, unveiling galaxies and intergalactic gas previously undetectable by telescopes.
A line intensity map showcasing the distribution of excited hydrogen in the universe approximately 10 billion years ago. The stars denote areas where HETDEX has identified galaxies. The inset simulates the structure after optimizing the data by reducing background noise. Image credit: Maja Lujan Niemeyer / Max Planck Institute for Astrophysics / HETDEX / Chris Byrohl / Stanford University.
“Studying the early Universe reveals how galaxies have evolved into their current forms and the role that intergalactic gas plays in this transformation,” stated Dr. Maya Lujan Niemeyer, an astronomer at the Max Planck Institute for Astrophysics and Ludwig Maximilian University of Munich, and a key member of the Hobby-Eberly Telescope’s Dark Energy Experiment (HETDEX).
“Many objects from this epoch are faint and challenging to observe due to their vast distances,” she continued.
“Through a technique known as line intensity mapping, this innovative map enhances our understanding of these objects, adding complexity and depth to this crucial era of cosmic history.”
Although line intensity mapping is not a novel methodology, this is the first instance it has been employed to visualize Lyman alpha emissions with such exceptional precision across an extensive dataset.
The HETDEX project harnesses the capabilities of the Hobby-Eberly Telescope to catalog over 1 million luminous galaxies to decode the mysteries of dark energy.
What differentiates this project is its extensive measurement scope, equivalent to observing more than 2,000 full moons and amassing a colossal dataset of over 600 million spectra across an expansive area of the sky.
“We leverage only a fraction of our data—approximately 5%,” remarked Dr. Karl Gebhardt, principal investigator of HETDEX and an astronomer at the University of Texas at Austin.
“This leaves significant potential for future research utilizing the remaining data.”
“While HETDEX captures images of the entire sky, only a small subset of the collected data comprises sufficiently bright galaxies for our research,” noted Dr. Lujan Niemeyer.
“These galaxies are merely the beginning. In the vast expanses in between, lies an entire ocean of light awaiting discovery.”
To construct this groundbreaking map, astronomers employed a supercomputer at the Texas Advanced Computing Center to meticulously analyze approximately half a petabyte of HETDEX data.
Using the coordinates of luminous galaxies already detected by HETDEX, they inferred the positions of fainter galaxies and adjacent glowing gas.
Due to the gravitational forces that cause matter to cluster, the existence of one bright galaxy implies the presence of nearby celestial objects.
“This allows us to utilize known galaxy positions as reference points to ascertain distances to fainter celestial entities,” explained Dr. Eiichiro Komatsu, HETDEX scientist and astronomer at the Max Planck Institute for Astrophysics.
“The resultant map emphasizes regions surrounding bright galaxies while providing intricate details of the areas in between.”
“Simulation models exist for this cosmic era, yet they remain hypothetical; they do not represent the actual universe.”
“We now possess a foundational understanding that allows us to verify whether the astrophysics underlying these simulations holds true.”
For more on these remarkable findings, published on March 3, 2026, in the Astrophysical Journal.
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Maya Lujan Niemeyer and others, 2026. Lyα intensity mapping in HETDEX: Galaxy-Lyα intensity cross-power spectrum. APJ 999, 177; doi: 10.3847/1538-4357/ae3a98
Source: www.sci.news
