eleanor FFI Light Curves From TESS (ELEANOR)
Primary Investigator: Benjamin Montet
HLSP Authors: Adina Feinstein, Benjamin Montet, Daniel Foreman-Mackey
Primary Reference(s): Feinstein et al. 2019
Citations: See ADS Statistics
The TESS mission has been providing the community with 30-minute Full-Frame Images, which contain about a million stars observed every sector. However, individual target pixel files (TPFs) and light curves (LCs) are not being released for these stars. The purpose of eleanor is to provide the community with systematics-corrected light curves for stars brighter than I = 16, for which the pipeline can achieve 1% precision photometry.
The eleanor pipeline is installable through the Python package index via pip and can also be found on GitHub. Users of the eleanor software and/or data products should cite Feinstein et al, 2019, https://zenodo.org/record/2597620#.XbnzkkVKjBI.
The first eleanor data product release contains time-stacked postcards as well as estimated 2D backgrounds per postcard for Sectors 1-13. The postcards, coupled with the eleanor software, can be used to create individual TPFs and LCs for a given TIC ID, set of coordinates, or Gaia ID. For a Quickstart tutorial on the software, please refer to the eleanor documentation (http://adina.feinste.in/eleanor/).
The postcards are 148 x 104 pixel time-stacked cutouts of the FFIs from each Sector. Consecutive postcards across the detector overlap by 50 pixels to avoid edge effects. The team also models a 2D background across each cadence of each postcard. These backgrounds are in the same format as the postcards, but are stored in the *_bkg.fits files. The pointing model files contain a 3x3 affine transformation for each cadence based on the (RA, Dec) vs. (x,y) coordinate position across the CCD. Each 9x1 row in the file is one cadence that requires reshaping before applying to a set of coordinates. The pointing model is used behind the scenes in the eleanor software. The documentation on using the pointing model outside of eleanor can be found here.
The postcards are sorted into sub-directories based on Sector (as a four-digit zero-padded integer) and camera-chip number, for instance, postcards from Sector 4, Camera 2, Chip 3 will be in a directory:
The data file naming convention is as follows for the postcards:
And the naming convention for the pointing model files are:
- <sector> = The 4-digit, zero-padded Sector number, e.g., "s0004"
- <cam-chip> = The camera and chip number this postcard belongs to, e.g., "2-3" for Camera 2, Chip #3
- <xpixel> = The x position of the lower left corner of the postcard in pixel coordinates
- <ypixel> = The y position of the lower left corner of the postcard in pixel coordinates
- <version> = A string denoting the version of the postcard file, e.g., "v2"
- <exten> = The file type
Data file types:
|_pc.fits||Postcard data file, background-subtracted.|
|_bkg.fits||Postcard background data file.|
|_pm.txt||Pointing model across the Camera and Chip.|
eleanor data products are available in the MAST Portal and astroquery.mast. For postcards, users are encouraged to use the cutout functionality of the eleanor software package, unless you need a small number of full-sized postcards. Note: there are more than 10,000 postcards per Sector, thus a request for all postcards from a given Sector might time out, dependent on internet bandwidth and traffic at MAST.