Unlocking the mystery of the Cosmic Infrared Background

Published: 26th April, 2024, Academia Sinica, Institute of Astronomy & Astrophysics (ASIAA), Taiwan

Utilizing the SCUBA-2 camera mounted on the James Clerk Maxwell Telescope in Hawaii, an international team led by graduate student Qi-Ning Hsu and Dr. Chian-Chou Chen from the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) has successfully resolved the cosmic infrared background (CIB) at 450 μm and confirmed its origin from galaxies beyond the Milky Way. The result has published in the Astrophysical Journal Letters in March, 2024.

ASIAA is thrilled to announce a groundbreaking achievement in astronomy, marking a significant leap forward in our understanding of the universe. A research team from National Tsing Hua University, ASIAA, University of Hawaii at Manoa, and University of Wisconsin-Madison, has successfully resolved the cosmic infrared background light at 450 μm, thanks to the extraordinary capabilities of the SCUBA-2 camera mounted on the James Clerk Maxwell Telescope and the profound effects of strong gravitational lensing.

“The achievement underscores the exceptional observational conditions provided by the summit of Mauna Kea, which enable breakthrough discoveries like this to occur in only a handful of locations worldwide,” said Dr. Lennox Cowie, an astronomer at the University of Hawaii at Manoa. 

The cosmic infrared background is a faint glow of light that permeates the universe, likely originating from the cumulative emissions of stars and galaxies throughout cosmic history. Despite its importance in deciphering cosmic evolution, confirming the origin of CIB remains an open question, and accurately measuring the CIB has posed challenges due to its low intensity and the difficulty in accessing the appropriate atmospheric windows from the ground.

Through the innovative utilization of strong gravitational lensing provided by foreground massive galaxy clusters, the research team has achieved a breakthrough in resolving the CIB at 450 μm with unprecedentedly sensitive observations. Gravitational lensing, a phenomenon predicted by Einstein's theory of general relativity, magnifies and distorts light from distant sources, amplifying their faint signals and enabling us to probe deeper into the cosmos than ever before.

"The complete resolution of the cosmic infrared background at 450 μm represents a monumental advancement in our comprehension of the universe's evolution,” said Dr. Chian-Chou Chen, an assistant research fellow at ASIAA. "By harnessing the power of strong gravitational lensing in conjunction with the state-of-the-art SCUBA-2 camera, we have unlocked new insights into the early stages of cosmic history,” said the lead author Qi-Ning Hsu, a PhD student at the National Tsing Hua University.

Furthermore, their analysis has confirmed that the origin of the CIB is unequivocally extragalactic, originating from galaxies beyond our own Milky Way. This confirmation not only enhances our understanding of the cosmic infrared background but also sheds light on the distribution and evolution of galaxies throughout the universe. This achievement not only deepens our understanding of astrophysical phenomena but also has far-reaching implications across various scientific disciplines, including cosmology and galaxy formation. By unraveling the mysteries of the cosmic infrared background, astronomers take significant strides toward unraveling the complex tapestry of the cosmos.

(Background) Illustration of cosmic background radiation taken by the COBE satellite. The origin of the background light in infrared remains an open question. (Right panel) An example 450 μm image taken by the SCUBA-2 camera where the red circles show the detected galaxies. This groundbreaking observations clearly show that these galaxies are the origin of the 450 μm background light. Image Credit: COBE/Hsu et al.

More Information:

This research presented in a paper "A Full Resolution of the 450 μm Extragalactic Background Light,” by Hsu et al. has appeared in the Astrophysical Journal Letters on March 28th, 2024.

Media Contact:

Dr. Chian-Chou Chen, Email: ccchen@asiaa.sinica.edu.tw, Tel: +886 2 2366 5451