Big Bang, Big Data, Big Iron: Fifteen Years of Cosmic Microwave Background Data Analysis at NERSC

The cosmic microwave background (CMB) consists of photons created in the Big Bang and cooled by the subsequent expansion of the universe to an almost perfectly uniform 3-Kelvin sky signal today. These photons experience the entire history of the universe, and each epoch has left its imprint as tiny fluctuations in their temperature and polarization. Decoding these provides unique insight into the history of the universe, constraining the fundamental parameters of both cosmology and high-energy physics. The faintness of these fluctuations requires us "researchers" to gather huge datasets and analyze them on supercomputers. For 15 years, the National Energy Research Scientific Computing Center (NERSC) has provided the resources for the CMB community\´s most computationally challenging analyses. In this article, the authors describe how their analysis algorithms and implementations have evolved over this time, driven by both the growth in CMB data volumes and the changes in high-performance computing architectures.