The Lomb-Scargle Periodogram (after Lomb [1], and Scargle [2])
is a commonly-used statistical tool designed to detect periodic signals
in unevenly-spaced observations.
The lombscargle package contains a unified interface to several
implementations of the Lomb-Scargle periodogram, including a fast O[NlogN]
implementation following the algorithm presented by Press & Rybicki [3].
The code here is adapted from the gatspy package,
described in [4] and [5].
Scargle, J. D. “Studies in astronomical time series analysis. II -
Statistical aspects of spectral analysis of unevenly spaced data”.
ApJ 1:263 pp. 835-853 (1982)