Researchers have achieved a significant milestone in the field of astrophysics by obtaining the first astronomical spectrum using skipper charge-coupled devices (CCDs) on the 4.1-meter Southern Astrophysical Research Telescope. The results, presented by Edgar Marrufo Villalpando, a physics PhD candidate at the University of Chicago and a Fermilab DOE Graduate Instrumentation Research Award Fellow, mark a major step forward for skipper-CCD technology and its potential applications in cosmology.
Alex Drlica-Wagner, a cosmologist at Fermilab who led the project, emphasized the importance of this achievement, stating, “This is a major milestone for skipper-CCD technology. It helps to retire the perceived risks for using this technology in the future, which is vitally important for future DOE cosmology projects.”
The Need for Advanced Technology in Cosmology
Cosmologists aim to unravel the mysteries of dark matter and dark energy by studying the distributions of stars and galaxies. To accomplish this, they require advanced technology capable of detecting fainter, more distant astronomical objects with minimal noise. While existing CCD technology can make these measurements, it is either time-consuming or less efficient.
Skipper CCDs, introduced in 1990, offer a solution by reducing electronic noise to levels that allow the measurement of individual photons. By taking multiple measurements of interesting pixels and skipping the rest, skipper CCDs increase the precision of measurements in specific regions of the image while reducing total readout time.
First Astronomical Observations with Skipper CCDs
On March 31 and April 9, researchers used skipper CCDs in the SOAR Integral Field Spectrograph to collect astronomical spectra from various celestial objects, including a galaxy cluster, two distant quasars, a galaxy with bright emission lines, and a star potentially associated with a dark-matter-dominated ultra-faint galaxy. This marked the first time skipper-CCD technology was used to observe the night sky and collect astronomical data, achieving sub-electron readout noise and counting individual photons at optical wavelengths.
“What’s incredible is that these photons traveled to our detectors from objects billions of light-years away, and we could measure each one individually,” said Marrufo Villalpando.
Jim Janesick, the inventor of the skipper CCD and a distinguished engineer at SRI International, expressed his surprise and excitement about the technology’s resurgence and the impressive noise results.
As researchers continue to analyze data from these first observations and plan for future runs, they are already working on improving skipper-CCD technology. The next generation of skipper CCDs, developed by Fermilab and Lawrence Berkeley National Laboratory, is 16 times faster than current devices, greatly reducing readout time. These new devices have been identified for use in future DOE cosmology efforts and are being considered by NASA for the forthcoming Habitable Worlds Observatory.
