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arXiv · 2509.05527

The Schwarzschild-Couder Telescope for the Cherenkov Telescope Array Observatory

Luca Riitano·Justin Vandenbroucke·Zach Curtis-Ginsberg
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Abstract

The Cherenkov Telescope Array Observatory (CTAO) will greatly improve upon sensitivities in the field of very-high-energy gamma-ray astrophysics. The CTAO northern site (CTAO-North, La Palma, Spain) currently hosts LST-1 with the remaining three large-sized telescopes (LSTs) expected in mid-2026 and one medium-sized telescope (MST) expected in mid-2027. The CTAO southern site (CTAO-South, Paranal, Chile) expects the delivery of five small-sized telescopes (SSTs) and two MSTs in early 2026 with on-site construction beginning in mid-2026. The dual-mirrored Schwarzschild-Couder Telescope (SCT) is a candidate MST for CTAO-South and is capable of observations in the energy range of 100 GeV to 10 TeV, the core of CTAO's 20 GeV to 300 TeV energy range. Inaugurated in January 2019, the prototype SCT (pSCT) located at the Fred Lawrence Whipple Observatory in southern Arizona observed gamma-ray emission from the Crab Nebula at a significance of 8.6 sigma in 2020. The pSCT utilizes a novel dual-mirror optics design and a densely packed focal plane of silicon photomultipliers (SiPMs). An upgrade of the pSCT camera is underway to fully instrument the camera with 11,328 pixels and an 8-degree diameter FoV. In addition, upgraded electronics will lower the front-end electronics noise, allowing for a lower trigger threshold and improved event reconstruction and background rejection. This work will present the status of the upgrade of the pSCT and discuss the future of the SCT.

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Luca Riitano, Justin Vandenbroucke, Zach Curtis-Ginsberg. 2025-09-05. The Schwarzschild-Couder Telescope for the Cherenkov Telescope Array Observatory. https://arxiv.org/abs/2509.05527

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