A Fast Chi-squared Technique For Period Search of Irregularly Sampled Data

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/227314A new, computationally- and statistically-efficient algorithm, the Fast $χ^2$ algorithm, can find a periodic signal with harmonic content in irregularly-sampled data with non-uniform errors. The algorithm calculates the minimized $χ^2$ as a function of frequency at the desired number of harmonics, using Fast Fourier Transforms to provide $O (N \log N)$ performance. The code for a reference implementation is provided.Source code for the reference implementation is available at http://public.lanl.gov/palmer/fastchi.html . Accepted by ApJ. 24 pages, 4 figuresData Analysis, Statistics and ProbabilityInstrumentation and Methods for AstrophysicsA Fast Chi-squared Technique For Period Search of Irregularly Sampled Datatext