The History of Gamma-Ray Astronomy at the Whipple Observatory

From humble beginnings just over three decades ago, the imaging atmospheric-Cherenkov technique (IACT) has evolved into an extremely powerful tool for studying gamma-rays emitted by the Universe’s most violent astrophysical objects at very high energies (VHE; >10¹⁰ eV). This technique complements lower-energy observations taken by satellites and ground-based telescopes, providing insight into the physical mechanisms powering these extreme astrophysical objects.

The Fred Lawrence Whipple Observatory, located in southern Arizona, pioneered this new branch of astronomy (VHE gamma-ray astronomy) and continues to be at the forefront of ongoing advancement of the IACT technique. This talk recounts the journey leading to, and beyond, the development of IACT at the Observatory. This commenced with the installation of the 10-meter gamma-ray telescope in 1968. Key milestones along the way were the first successful detection of VHE gamma rays from the Crab Nebula twenty years later in 1989 using Cherenkov imaging, stereoscopic imaging with the VERITAS array in 2007 and most recently, in 2019, deployment of the prototype Schwarzschild-Couder 9.7 m telescope in preparation for the next-generation VHE observatory CTA (Cherenkov Telescope Array). Current projects and developments at the Observatory will also be discussed.