Simulated Performance of Timescale Metrics for Aperiodic Light Curves

Abstract

Aperiodic variability is a characteristic feature of young stars, massive stars, and active galactic nuclei. With the recent proliferation of time domain surveys, it is increasingly essential to develop methods to quantify and analyze aperiodic variability. We develop three timescale metrics that have been little used in astronomy -- Δm-Δt plots, peak-finding, and Gaussian process regression -- and present simulations comparing their effectiveness across a range of aperiodic light curve shapes, characteristic timescales, observing cadences, and signal to noise ratios. We find that Gaussian process regression is easily confused by noise and by irregular sampling, even when the model being fit reflects the process underlying the light curve, but that Δm-Δt plots and peak-finding can coarsely characterize timescales across a broad region of parameter space. We make public the software we used for our simulations, both in the spirit of open research and to allow others to carry out analogous simulations for their own observing programs.

39 pages, 16 figures, 3 tables. To be published in The Astrophysical Journal. Simulation software is available online at http://ascl.net/1408.012

References in corpus (8)

• CSI 2264: Simultaneous optical and infrared light curves of young disk-bearing stars in NGC 2264 with CoRoT and Spitzer-- evidence for multiple origins of variability
• Results of the ROTOR-program. I. The long-term photometric variability of classical T Tauri stars
• Rotation and accretion of very low mass objects in the SigmaOri cluster
• A Correlation Between Pre-Main Sequence Stellar Rotation Rates and IRAC Excesses in Orion
• The Monitor project: Rotation of low-mass stars in NGC 2362 -- testing the disc regulation paradigm at 5 Myr
• Young Stellar Object Variability (YSOVAR): Long Timescale Variations in the Mid-Infrared
• On the reliability of microvariability tests in quasars
• Variability-based AGN selection using image subtraction in the SDSS and LSST era

Cited by in corpus (19)

• The many-faceted light curves of young disk-bearing stars in Upper Sco and $\rho$ Oph observed by $K2$ Campaign 2
• Comparative performance of selected variability detection techniques in photometric time series
• Photometric Variability of the Be Star Population
• A Simple Calculation in Service of Constraining the Rate of FU Orionis Outburst Events from Photometric Monitoring Surveys
• CSI 2264: Characterizing Young Stars in NGC 2264 with Stochastically Varying Light Curves
• Long-term variability of T Tauri stars using WASP
• The Many-Faceted Light Curves of Young Disk-bearing Stars in Taurus as Seen by K2
• Testing microvariability in quasar differential light curves using several field stars
• Spitzer Observations of Long Term Infrared Variability Among Young Stellar Objects in Chamaeleon I
• Characterising the i-band variability of YSOs over six orders of magnitude in timescale
• YSOVAR: mid-infrared variability of young stellar objects and their disks in the cluster IRAS 20050+2720
• How common is LBV S Dor variability at low metallicity?
• Variability, periodicity and contact binaries in WISE
• A ZTF Look at Optical Variability of Young Stellar Objects in the North America and Pelican Nebulae Complex
• A Method to Measure the Unbiased Decorrelation Timescale of the AGN Variable Signal from Structure Functions
• Outbursting Young Stellar Object PGIR 20dci in the Perseus Arm
• A survey for variable young stars with small telescopes: II -- Mapping a protoplanetary disk with stable structures at 0.15 AU
• Towards an understanding of YSO variability: A multi-wavelength analysis of bursting, dipping, and symmetrically varying light curves of disc-bearing YSOs
• Exploring Young Stellar Variability with Gaia DR3 light curves