Exposure-based Algorithm for Removing Systematics out of the CoRoT Light Curves

TL;DR

This paper introduces a simple, exposure-based algorithm that effectively removes instrumental systematics from CoRoT light curves by modeling effects based on CCD position and aperture, improving data quality.

Contribution

The novel algorithm accounts for instrumental effects using only exposure parameters, making it more robust and integrated into the CoRoT data processing pipeline.

Findings

Successfully detrended ~2% long-term variations in light curves

Algorithm is robust against stellar flux variations

Part of the official CoRoT data pipeline

Abstract

The CoRoT space mission was operating for almost 6 years, producing thousands of continuous photometric light curves. The temporal series of exposures are processed by the production pipeline, correcting the data for known instrumental effects. But even after these model-based corrections, some collective trends are still visible in the light curves. We propose here a simple exposure-based algorithm to remove instrumental effects. The effect of each exposure is a function of only two instrumental stellar parameters, position on the CCD and photometric aperture. The effect is not a function of the stellar flux, and therefore much more robust. As an example, we show that the $\sim2\%$ long-term variation of the early run LRc01 is nicely detrended on average. This systematics removal process is part of the CoRoT legacy data pipeline.