Precision Light Curves from TESS Full-Frame Images: A Difference Imaging Approach

Understand

The Transiting Exoplanet Survey Satellite (TESS) will observe $\sim$150~million stars brighter than $T_{\rm mag} \approx 16$, with photometric precision from 60~ppm to 3~percent, enabling an array of exoplanet and stellar astrophysics investigations.While light curves will be provided for $\sim$400,000 targets observed at 2-min cadence, observations of most stars will only be provided as full-frame images (FFIs) at 30~min cadence.

• The TESS image scale of $\sim21$''/pix is highly susceptible to crowding, blending, and source confusion, and the highly spatially variable point spread function (PSF) will challenge traditional techniques, such as aperture and Gaussian-kernel PSF photometry.
• We use official "End-to-End~6" TESS simulated FFIs to demonstrate a difference image analysis pipeline, using a $\delta$-function kernel,that achieves the mission specification noise floor of 60~ppm~hr$^{-1/2}$.
• We show that the pipeline performance does not depend on position across the field, and only $\sim$2\% of stars appear to exhibit residual systematics at the level of $\sim$5~ppt.