Adrienne Erickcek, an assistant professor in the UNC-CH Physics and Astronomy department, has been received an National Science Foundation (NSF) CAREER award to support her investigation of how the evolution of the Universe during its first second affects the distribution and annihilation rate of dark matter.   The Faculty Early Career Development (CAREER) Program aims to identify early-career faculty members who excel in both research and education, and these 5-year awards are among the most prestigious offered by the NSF.

Titled “CAREER: Illuminating the Early Universe with Dark Matter,” Prof. Erickcek’s award supports her use of dark matter annihilation signals to close a troubling gap in the cosmological record.  Observations of the cosmic microwave background indicate that the Universe experienced a period of accelerated expansion, called inflation, shortly after the Big Bang, but it is not known what drove inflation, why it ended, and how the Universe became hot enough for Big Bang nucleosynthesis to occur a few minutes after inflation.  Prof. Erickcek’s group at UNC has demonstrated that smallest clumps of dark matter provide a way to probe this gap because their abundance is affected by the amplitude of the density fluctuations created during the final stages inflation and the evolution of the Universe during immediately after inflation.   These dark matter microhalos are very dense, making it more likely that the dark matter particles within them will collide and annihilate.  Consequently, the absence of a detection of dark matter annihilation limits the microhalo population, which in turn constrains the evolution of the early Universe.  Prof. Erickcek aims to use these observational constraints to derive robust limits on small-scale primordial fluctuations that will improve our understanding of inflation and to narrow the field of potential dark-matter candidates by restricting their production mechanisms.

This CAREER award also supports a collaboration between Prof. Erickcek and educators at the Morehead Planetarium and Science Center to develop an inquiry-based curriculum module for high school students that will incorporate the evidence for dark matter into lessons on Newtonian mechanics, thereby exposing students to one of the great mysteries of cosmology. This module will be made publicly available, and Professor Erickcek will lead professional-development workshops at North Carolina teaching conferences to train high-school teachers to use this module in their classrooms.

Density projections of simulated Earth-mass microhalos; the scale of each image is 0.025 pc. The microhalo on the left formed in a cosmology with no early matter-dominated era (EMDE). The microhalo on the right formed following an EMDE; it contains far more substructure, which will boost the dark matter annihilation rate within the halo.

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