FINKER: Frequency Identification through Nonparametric KErnel Regression in astronomical time series

Astronomy and Astrophysics, vol. 686, pp. A158

Abstract

Context. Optimal frequency identification in astronomical datasets is crucial for variable star studies, exoplanet detection, and astero-seismology. Traditional period-finding methods often rely on specific parametric assumptions, employ binning procedures, or overlook the regression nature of the problem, limiting their applicability and precision. Aims. We introduce a universal- nonparametric kernel regression method for optimal frequency determination that is generalizable, efficient, and robust across various astronomical data types. Methods. FINKER uses nonparametric kernel regression on folded datasets at different frequencies, selecting the optimal frequency by minimising squared residuals. This technique inherently incorporates a weighting system that accounts for measurement uncertainties and facilitates multi-band data analysis. We evaluated our method’s performance across a range of frequencies pertinent to diverse data types and compared it with an established period-finding algorithm, conditional entropy. Results. The method demonstrates superior performance in accuracy and robustness compared to existing algorithms, requiring fewer observations to reliably identify significant frequencies. It exhibits resilience against noise and adapts well to datasets with varying complexity.

Authors 5

1. Fiorenzo Stoppa

   Radboud University Nijmegen

   Affiliation as printed

   Department of Astrophysics/IMAPP, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands

   Department of Mathematics/IMAPP, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands

2. C. Johnston

   Radboud University Nijmegen · Max Planck Institute for Astrophysics · KU Leuven

   Affiliation as printed

   Department of Astrophysics/IMAPP, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands

   Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium

   Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Straße 1, 85741 Garching bei München, Germany

   Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium

3. Eric Cator

   Radboud University Nijmegen

   Affiliation as printed

   Department of Mathematics/IMAPP, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands

4. Gijs Nelemans Aachen Netherlands Institute for Space Research

   Radboud University Nijmegen · Space Research Organisation Netherlands · KU Leuven

   Affiliation as printed

   Department of Astrophysics/IMAPP, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands

   Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium

   SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands

   Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium

   SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, NL-3584 CA Utrecht, The Netherlands

5. P. Groot

   Radboud University Nijmegen · University of Cape Town · Inter-university Institute for Data Intensive Astronomy · South African Astronomical Observatory

   Affiliation as printed

   Department of Astronomy and Inter-University Institute for Data Intensive Astronomy, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa

   Department of Astrophysics/IMAPP, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands

   South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa

   South African Astronomical Observatory, P.O. Box 9, Observatory, 7935, South Africa