Optimal Photon Counting with Fast, Low Noise Astronomical Imagers
Abstract
Measuring rapid astrophysical phenomena requires many short exposures, which suffer from repeated read noise. A variety of recent technologies are achieving sub-electron read noise, which enable rapid time-domain studies of faint sources. These data can be analyzed with traditional methods, but the ability to resolve individual electrons enables a new class of more precise, photon-counting techniques. We present a photon-counting method for sub-electron read noise detectors which delivers optimal statistical uncertainties. We focus on Complementary Metal-Oxide-Semiconductor (CMOS) detectors and demonstrate our method on optical data collected by CMOS instrument "proto-Lightspeed," recently commissioned at the Magellan Clay telescope at Las Campanas Observatory. The method can be applied to non-CMOS detectors as well, such as skipper CCDs and linear-mode avalanche photodiodes. The method substantially improves analysis of faint sources, increasing signal to noise ratios by up to ∼ 130%, which would require 5.3× more observing time to accomplish with data alone. As an example we show detections of four normal rotation-powered pulsars with confirmed optical pulses, achieved in under two hours of total exposure. We provide the lightspeedpy pipeline for reducing proto-Lightspeed data with both photon counting and standard techniques.
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BibTeX
@misc{dinsmore2026optimal,
title = {{Optimal Photon Counting with Fast, Low Noise Astronomical Imagers}},
author = {Jack T. Dinsmore and Christopher Layden and Roger W. Romani and Vera L. Berger and Kevin B. Burdge and Geoffrey Mo and Deepto Chakrabarty and Emma T. Chickles and Gabor Furesz and Juliana García-Mejía and Dave Osip and Jack Piotrowski},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.07137},
eprint = {2610.07137},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.07137},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Optimal Photon Counting with Fast, Low Noise Astronomical Imagers
AU - Jack T. Dinsmore
AU - Christopher Layden
AU - Roger W. Romani
AU - Vera L. Berger
AU - Kevin B. Burdge
AU - Geoffrey Mo
AU - Deepto Chakrabarty
AU - Emma T. Chickles
AU - Gabor Furesz
AU - Juliana García-Mejía
AU - Dave Osip
AU - Jack Piotrowski
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2610.07137
UR - https://arxiv.org/abs/2610.07137
AB - Measuring rapid astrophysical phenomena requires many short exposures, which suffer from repeated read noise. A variety of recent technologies are achieving sub-electron read noise, which enable rapid time-domain studies of faint sources. These data can be analyzed with traditional methods, but the ability to resolve individual electrons enables a new class of more precise, photon-counting techniques. We present a photon-counting method for sub-electron read noise detectors which delivers optimal statistical uncertainties. We focus on Complementary Metal-Oxide-Semiconductor (CMOS) detectors and demonstrate our method on optical data collected by CMOS instrument "proto-Lightspeed," recently commissioned at the Magellan Clay telescope at Las Campanas Observatory. The method can be applied to non-CMOS detectors as well, such as skipper CCDs and linear-mode avalanche photodiodes. The method substantially improves analysis of faint sources, increasing signal to noise ratios by up to ∼ 130%, which would require 5.3× more observing time to accomplish with data alone. As an example we show detections of four normal rotation-powered pulsars with confirmed optical pulses, achieved in under two hours of total exposure. We provide the lightspeedpy pipeline for reducing proto-Lightspeed data with both photon counting and standard techniques.
ER -