QhX: A Python package for periodicity detection in red noise

QhX is a Python package for detecting periodicity in red noise time series, developed as an in-kind contribution to the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST, Ivezić et al., 2019).Traditional Fourier-based methods often struggle with red noise, which is common in quasar light curves and other accreting objects.QhX addresses these challenges with its core 2-dimensional (2D) hybrid method (Kovačević et al., 2018).Input data are mapped into a time-period plane via wavelet transforms, which are (auto)correlated to produce a correlation density map in a "period-period" plane.Statistical vetting incorporates significance, upper and lower error bounds, and the novel intersection over union (IoU) metric to evaluate the proximity and overlap of detected periods across bands and objects.In addition to a vetted numerical catalog, QhX dynamically visualizes periodicity across photometric bands and objects.