A Detection Threshold in the Amplitude Spectra Calculated from TESS Time-Series Data

TL;DR

This paper investigates the detection threshold in amplitude spectra derived from TESS space-based photometry, providing a formula to estimate thresholds for various false alarm probabilities and data parameters.

Contribution

It introduces a method to estimate detection thresholds in TESS data, highlighting the need for higher S/N ratios in space-based photometry to prevent false detections.

Findings

Detection threshold depends on false alarm probability and data points

Higher S/N ratios are necessary for space-based photometry compared to ground-based

A formula for estimating detection thresholds is provided

Abstract

We present results of time-series data simulation. We aimed at estimating the threshold used for detecting signals in amplitude spectra, calculated from simulating TESS photometry of up to one year duration. We selected the threshold at a false alarm probability FAP=0.1% and derived S/N ratios between 4.6 and 5.7 depending on the data cadence and coverage. We also provide a formula to estimate the threshold for any FAP adopted and a given number of data points. Our result confirms that, to avoid spurious detection, space-based photometry may require substantially higher S/N than that typically being employed for ground-based data.