OVERVIEW OF THE KEPLER SCIENCE PROCESSING PIPELINE

Abstract

The Kepler Mission Science Operations Center (SOC) performs several critical functions including managing the ∼156,000 target stars, associated target tables, science data compression tables and parameters, as well as processing the raw photometric data downlinked from the spacecraft each month. The raw data are first calibrated at the pixel level to correct for bias, smear induced by a shutterless readout, and other detector and electronic effects. A background sky flux is estimated from ∼4500 pixels on each of the 84 CCD readout channels, and simple aperture photometry is performed on an optimal aperture for each star. Ancillary engineering data and diagnostic information extracted from the science data are used to remove systematic errors in the flux time series that are correlated with these data prior to searching for signatures of transiting planets with a wavelet-based, adaptive matched filter. Stars with signatures exceeding 7.1σ are subjected to a suite of statistical tests including an examination of each star's centroid motion to reject false positives caused by background eclipsing binaries. Physical parameters for each planetary candidate are fitted to the transit signature, and signatures of additional transiting planets are sought in the residual light curve. The pipeline is operational, finding planetary signatures and providing robust eliminations of false positives.

Flagging and correction of pattern noise in the Kepler focal plane array

“…An undershoot correction is also included in the current calibration pipeline with a model accounting extending up to 20 pixels when they are included in the target table. 6 We have observed, and continue to expect the start-of-line ringing to be sufficiently stable over time to avoid photometric precision degradation.…”

“…These investigations determined that several did not require mitigation. The existing data processing pipeline 6 , or the algorithms described herein handle those with the largest impact. Those relevant to this paper are briefly described below and illustrated in Figure 2.…”

“…Previously, authors have described mission design and overall performance 2 , photometer design 3,4 , in-flight instrument performance 5,8 , and the overall data processing scheme 6 . Caldwell et al 4 describes several nonstationary image artifacts that are present in Kepler data and discusses their impact on photometric precision.…”

Study of the Time-Series of Microvariability in Kepler Blazar W2R 1926+42

“…In Quarter 14, the object was monitored in the short cadence mode for 100 days. In the automated Kepler data processing pipeline, the flux of the object is calculated by simple aperture photometry (SAP) [14]. The center of its observing wavelength is λ = 6600 Å [15,16].…”

Photometer performance assessment in Kepler science data processing

“…Photometer Performance Assessment (PPA) is one of the software components of the science data processing pipeline of the Kepler mission 3,4 . One task of PPA is to analyze the health and performance of the Kepler photometer.…”