Wider Bandwidth, Deeper Insights

New ALMA GPU Spectrometer Advances to Next Phase

The Atacama Large Millimeter/submillimeter Array (ALMA) hsgas reached an important milestone in its Wideband Sensitivity Upgrade (WSU) program: the Total Power GPU Spectrometer (TPGS) has successfully passed its Preliminary Design Review (PDR). This achievement marks a significant step toward expanding ALMA's spectral capabilities and enabling new scientific opportunities across a broad range of astrophysical studies.

The TPGS is a next-generation spectrometer designed for the Total Power antennas of the Atacama Compact Array (ACA), also known as the Morita Array. Once implemented, it will replace the current spectrometer system, delivering wider bandwidth and improved spectral performance. These enhancements will allow astronomers to observe more efficiently across larger frequency ranges, opening new possibilities for studies of molecular clouds, star formation, galaxy evolution, and the chemical complexity of the universe.

Developed as a major East Asian contribution to the WSU program, the project is being carried out by the Korea Astronomy and Space Science Institute (KASI) and the National Astronomical Observatory of Japan (NAOJ), in close collaboration with the Joint ALMA Observatory (JAO) and its international partnership.

The Preliminary Design Review is a key stage in developing new ALMA instrumentation, assessing system requirements, external interfaces, technical feasibility, and potential risks. After submitting detailed design documentation in early December, the development team conducted an extensive external review with an international panel of experts from JAO, NAOJ, the European Southern Observatory (ESO), the National Radio Astronomy Observatory (NRAO) of the United States of America, the National Research Council (NRC) of Canada, ASTRON (Netherlands), and the Kitami Institute of Technology (Japan). Over the following weeks, reviewers provided detailed technical feedback that guided refinements to the baseline design.

The final review meeting took place on 28–29 January 2026 in Daejeon, Republic of Korea, where engineers, scientists, and project representatives gathered to discuss remaining open items and define action plans for the next phase. The review panel expressed strong confidence in the design's maturity and overall coherence, while also offering constructive guidance to support continued development.

As a key technological upgrade within the Wideband Sensitivity Upgrade program, the TPGS will help ensure that ALMA remains at the forefront of millimeter- and submillimeter astronomy. By increasing bandwidth and enhancing spectral capabilities, the new spectrometer will strengthen ALMA's ability to conduct large spectral surveys, study faint signals across wide frequency ranges, and support stable long-term operations.

The successful completion of the Preliminary Design Review represents an important milestone on the path toward implementing the next generation of ALMA instrumentation, reinforcing the observatory's role as a global platform for cutting-edge astronomical discovery.

Additional Information

ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSTC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.