The TESS mission has several data products ranging from the TESS input catalog to a catalog of planet candidates. Here we give an overview of what information is in each data product.
TESS obtains time-series photometry at two different cadences with a baseline ranging from ~27 days to a full year, depending on sector overlap. An overview of the primary pixel-level science products are shown above. The entire set of CCDs for each TESS sector are downloaded every 30-minutes, these are known as the Full Frame Images (FFIs). Certain groups of pixels are also downloaded at a 2-minute cadence in order to obtain a faster cadence for a subset of targets, these are known as Target Pixel (TP) files. The pixels around a selected star are stored as arrays in these target-pixel files, one image per time stamp. Aperture photometry is performed on each image creating an array of fluxes; these are known as Light Curve (LC) files. See the Science Product Handbook for more detailed information on file formats and content.
Cotrending Basis Vectors (CBV) (_cbv.fits): The cotending basis vectors represent the set of systematic trends present in the ensemble light curve data for each CCD and can be used to remove common instrumental systematics from the data. These vectors are created by the pipeline to produce the detrended flux time series (PDCSAP_FLUX) in the light curve files. The CBVs can be fit to individual aperture photometry light curves (known as SAP_FLUX) on the same channel in order to fine tune the detrending.
Quality Flags Table The TESS pipeline populates a series of quality flags to indicate when a cadence may have been taken during an anomalous event. These flags are available in the light curve files, the target pixel files, and a subset are available for the FFIs (via a logical AND across the short cadences). The following table describes the meaning of each flag.
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Aperture Mask Image Bit TableThe light curve files and target pixel files contain an image in the APERTURE FITS extension that describes how each pixel was used in the processing. The integer values of this image are the bit-wise OR of the bits described in the following table.
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TESS provides several catalogs of target stars in order to choose which stars will be observed at the 2-minute cadence.
The flux time series for each star observed in short cadence are then further detrended and searched for transits. The repeating signals that are identified in this way are known as Threshold Crossing Events (TCE). The following products are produced by the TESS Science Processing Pipeline for each target star that produces a TCE.
Exoplanet Result Catalogs
TESS produces several catalogs of possibly transit-like, periodic signals found in the TESS data. As signals are vetted they are can be included in the next catalog down. The catalog of signals with the least amount of vetting are the Threshold Crossing Events (TCEs) which are produced by the SPOC Pipeline. Other groups may also search the short cadence light curves, or the longer cadence FFIs for signals that may be consistent with transiting exoplanets. Since these signals have little-to-no vetting, the reliability can be quite low. Signals found in the data are then turned into TESS Objects of Interest (TOI) once the signal is vetted and determined to be sufficiently consistent with a transit or eclipse. The TOI list contains both planet candidates and false positives, but these are the signals that are worthy of follow-up observations. Once follow-up measurements, or additional analysis, reveal the mass of the transiting object, or remove all doubt that the signal could be caused by an eclipsing binary, the planet is considered confirmed.
Engineering Files