Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Details of the eleanor Pipeline

Adina
December 10, 2020

Details of the eleanor Pipeline

These slides were presented virtually at the Earth 2.0 workshop I on December 10, 2020.

Adina

December 10, 2020
Tweet

More Decks by Adina

Other Decks in Science

Transcript

  1. Unpacking eleanor, a Python tool for TESS FFI light curve

    extraction Adina Feinstein, Benjamin Montet, Dan Foreman-Mackey, Megan Bedell, Nicholas Saunders, Jacob Bean, Jessie Christiansen, Christina Hedges, Rodrigo Luger, Daniel Scolnic, José Vinícius de Miranda Cardoso !1 December 10, 2020 ET Workshop @afeinstein20
  2. eleanor was really designed with the user in mind. !3

    • Flexibility • Durability • Open source • Well documented • Easy to integrate with other software
  3. What steps are taken to extract and create a light

    curve? !4 • Background estimation & subtraction • Aperture selection • Creation of quality flags • Detrending using co-trending basis vectors (CBVs) • Optimization of light curve for transit searches
  4. What steps are taken to extract and create a light

    curve? !5 • Background estimation & subtraction • Aperture selection • Creation of quality flags • Detrending using co-trending basis vectors (CBVs) • Optimization of light curve for transit searches
  5. The eleanor pipeline takes the FFIs and breaks them into

    smaller, more space manageable “postcards.” !6
  6. Background approach #1: We mask the stars and estimate a

    constant background from each cadence across the postcard. !7
  7. Background approach #2: After masking bright sources, we linearly interpolate

    across the postcard to model the expected background. !8
  8. Background approach #3: We estimate a constant background from each

    cadence from the Target Pixel File (TPF). !10
  9. There is a difference between the postcard and TPF estimated

    1D backgrounds, but both capture large features nicely. !11
  10. We store each of the three backgrounds in the eleanor

    FITS file and indicate the best background through the header keyword `BKG_LVL`. !12
  11. What steps are taken to extract and create a light

    curve? !13 • Background estimation & subtraction • Aperture selection • Creation of quality flags • Detrending using co-trending basis vectors (CBVs) • Optimization of light curve for transit searches
  12. We test out a variety of aperture shapes, sizes, and

    pixel weightings for each target. !14
  13. What steps are taken to extract and create a light

    curve? !17 • Background estimation & subtraction • Aperture selection • Creation of quality flags • Detrending using co-trending basis vectors (CBVs) • Optimization of light curve for transit searches
  14. Quality flags are taken from the 2-minute targets and we

    create our own from regions with large, non-astrophysical centroid motions and bad background. !18
  15. What steps are taken to extract and create a light

    curve? !20 • Background estimation & subtraction • Aperture selection • Creation of quality flags • Detrending using co-trending basis vectors (CBVs) • Optimization of light curve for transit searches
  16. The co-trending basis vectors are provided by the SPOC pipeline.

    We bin them down to 30-minutes to work with the FFIs. !21
  17. The eleanor light curves are optimized for transit searches by

    calculating the combined differential photometric precision (CDPP). !22 eleanor corrected flux light curve for CDPP calculation
  18. The corrected flux is a combination of CBVs and regressing

    against a linear model of position, background, and time. !26
  19. The eleanor software allows for PSF modeling of light curves.

    This is not available in the data product. !28
  20. There are pros and cons to each of the flux

    options created through eleanor. !29 Raw Corrected PCA PSF Transits/eclipses x x x Long term trends x x Short term variability x x Solar system science x
  21. eleanor was really designed with the user in mind. !30

    • Flexibility • Durability • Open source • Well documented • Easy to integrate with other software
  22. Software users are also able to input their own apertures

    and apply all of the eleanor detrending techniques. !32
  23. eleanor was really designed with the user in mind. !34

    • Flexibility • Durability • Open source • Well documented • Easy to integrate with other software
  24. eleanor was really designed with the user in mind. !36

    • Flexibility • Durability • Open source • Well documented • Easy to integrate with other software
  25. By creating thorough example notebooks, and updating them as we

    learned, makes it easy for users to explore their own science with our tool. !37
  26. eleanor was really designed with the user in mind. !38

    • Flexibility • Durability • Open source • Well documented • Easy to integrate with other software
  27. One of the biggest lessons learned is to check different

    light curves to make sure your source is truly astrophysical. !39 OS19 = Oelkers & Stassun (2019) TASOC = TESS Asteroseismic Science Consortium
  28. eleanor Resources !41 • PASP paper: https://ui.adsabs.harvard.edu/abs/2019PASP..131i4502F/abstract • Documentation: http://adina.feinste.in/eleanor

    • GitHub: https://github.com/afeinstein20/eleanor • YouTube Tutorial: https://www.youtube.com/watch?v=xpvniFrA6V0 • ET Google Colab Notebook: https://bit.ly/3mXY9ex