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, how it is produced and how the data is formatted.
Photometric Data Products
TESS obtains time-series photometry at two different cadences with a baseline ranging from 3 weeks out to a year. An overview of the primary 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). Selected sections of sky are also downloaded at a 2-minute cadence. The the pixels at each time stamp are stored as arrays in target-pixel files. Aperture photometry is performed on each image creating an array of fluxes; these are stored in a light curve file. See the Science Product Handbook for more detailed information on file formats and content.
- Full Frame Images (FFI, ffi.fits): These files contain the long cadence time series of the entire field of view, both an uncalibrated and calibrated version are available.
- Target Pixel Files (TPF, .tp.fits): These files contain a time series of the raw and calibrated pixels downloaded at the 2-minute cadence.
- Light Curve Files (LCF, .lc.fits): These files contain the simple aperture photometry flux time series derived from the calibrated short-cadence pixels. It also contains a conditioned light curve that attempts to remove all signals except for astrophysical ones by co-trending against basis vectors derived from all stars observed in short cadence on the same camera.
Target Catalogs
- TESS Input Catalog (TIC): Catalog of stars used by the TESS mission to select targets to download at short cadence. The TIC is available through the MAST portal and via the API.
- Catalog Target List (CTL): Subset of the TIC containing each science groups priorities to obtain short cadence observations.
- Merged Target List:
Planet Search Products
The flux time series for each star observed in short cadence are then further detrended and searched for repeating signals consistent with a transiting planet, known as a Threshold Crossing Event (TCE). The following products are produced by the TESS Science Processing Pipeline for each target star that produces a TCE.
- DV Time Series Files (.dvt.fits): These files contain the sector-stitched, detrended and whitened light curves searched by the TESS Pipeline. All TCEs found on a star in one search are contained in the same file.
- DV Reports (.dvr.pdf): These pdf files contain plots and statistics for each TCE. For example, the reports contain plots of folded light curves and in- and out-of transit difference images.
- DV One-Page Summary (.dvs.pdf): This one page summary contains a quick overview of each TCE and much of the most important information about the TCE to determine if the signal is likely caused by a transit or shows evidence of being caused by an eclipsing binary or instrumental noise. Each TCE gets its own file, so if multiple TCEs are found on the same target star, there will be multiple pdf files.
Results Catalogs
As the diagram above indicates, there are several overlapping populations of signals found in the TESS data that are related to the search for transiting planets. The TCEs found in the short cadence time series by the SPOC pipeline (as well as signals found by searching light curves created from the TESS FFIs) are 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. The false positives are those with evidence of being an eclipsing binary. Once follow-up measurements reveal the planet's mass the planet and a paper is published, the planet is considered confirmed.
- Threshold Crossing Events (TCE): List of ephemerides (TIC number, Period, epoch) of signals that are highly correlated with a transit train. For each TCE, the project provides a highly detrended light curve file and a report showing relevant plots to evaluate whether the signal is a planet. These signals are not vetted and include false positives and instrumental false alarms.
- TESS Objects of Interest (TOI): Table containing the list of signals that are consistent being a transiting planet. This catalog provides a disposition of either planet candidate or false positive which can change as more information is gathered about a target from follow-up and additional analysis of the data.
- Confirmed Planets : Transiting planets found in the TESS data for which follow-up data provide a mass of the planet. See the exoFOP-TESS page for more information about what follow-up data are available.