Meet the AAS 248 Plenary Speakers: Dr. Carolyn Kierans

Key Takeaways

• Kierans leads ComPair balloon prototype proving MeV gap technology
• COSI balloon captured 511 keV positron glow after 46‑day flight
• NASA plans full COSI satellite launch in August 2027
• Early‑career prize highlights her impact on high‑energy astrophysics
• Emphasizes mentorship and diverse role models for aspiring physicists

Pulse Analysis

The medium‑energy gamma‑ray window, often called the MeV gap, sits between traditional X‑ray and high‑energy gamma observations. Because photons in the 100 keV‑100 MeV range cannot be focused with conventional optics, astronomers must rely on massive detector arrays aboard high‑altitude platforms. This technical hurdle has left a swath of the high‑energy universe—supernova nucleosynthesis, black‑hole coronae, and the Galactic positron annihilation line—poorly mapped, limiting theoretical models of particle acceleration and matter‑antimatter interactions.

Balloon missions like the Compton Spectrometer and Imager (COSI) have begun to bridge that gap. In 2016, COSI floated for 46 days over New Zealand, capturing the Galaxy’s 511 keV glow with unprecedented sensitivity. The success propelled COSI into a dedicated NASA satellite scheduled for launch in August 2027, where continuous sky coverage will refine source catalogs and test dark‑matter annihilation scenarios. Building on that momentum, Dr. Kierans’s ComPair prototype demonstrated key detector technologies during a 2023 flight from New Mexico, proving that scalable, low‑background instruments can operate reliably in the stratosphere.

Beyond the science, Kierans’s story underscores a workforce challenge: the MeV gap’s advancement hinges on skilled engineers, graduate students, and postdoctoral researchers who design, build, and calibrate these complex payloads. By championing mentorship and visible role models—especially for women and underrepresented groups—she is cultivating a pipeline of talent essential for future missions. As the community prepares for the next generation of MeV observatories, the blend of cutting‑edge instrumentation and inclusive training will determine how quickly the hidden high‑energy universe becomes accessible.