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Date

 

Attendees

Apologies:

Meeting agenda:

  1. News & Announcements.
  2. NIRSpec pipeline validation updates: non-linearity and dark current discussion (Ubeda, all)
  3. Non-linearity experiments on NIRISS updates (Roy).
  4. TSO JWebbinar.
  5. Closing remarks.

Meeting slides

No slides today

Discussion items

TimeItemWhoNotes
5 mins

1. News & announcements

Everyone

How are proposal reviews going? All going quite well! For MIRI all TSOs are affected by the change in read mode so a bit of work. 

Nestor Espinoza from exoCTK contamination tool. it allows adding a binary companion that is not in 2MASS and helps visualize any possible contamination in the spectra. 






2. NIRSpec pipeline validation


Leonardo Ubeda

Nestor: objective is to validate the pipeline - physical units, do the algorithms make sense? Meeting every Tuesday at 9:30 am for a quick update on progress and ideas. 

Right now LU has validated up to the linearity step in Detector1 step. Using CV3 lengthy time series data (10k integrations) to investigate the linearity correction. 

Leonardo Ubedafollowing up on actions from 2 wks ago:

the mean of ratio(2-1/3-2) over just the pixels containing the flux, is 0.99554. not consistent with 1.

MRegan: this is very low illumination so not really as "stress test"

Birkmann: some actually go into saturation so some pixels do have high fluxes. count rates are high around 1-2 µm. 

Regan: ideally these data should then be separated out by flux. as there is a big range of fluxes across these illuminated pixels. 

LU will do this for the next meeting. 

More discussion about noise and reference files.






5min3. Non-linearity experiments


Unknown User (aroy)

the error on the non-linearity correction is flux dependent

MR: that is a problem. 

let's call it "fluence-dependent" errors. 

AR simulated a 1% transit in a single pixel. then draws from the linearity coefficients to generate an "observed" response in the pixel. using the same linearity coefficients but with a different random draws, then tries to recover the "true" response. This reveals the error on the non-linearity correction. 

MR has done this work as well using Legendre polynomials, with proper variances on the coefficients. 

AR: then repeated these draws 1000 times, and investigate the shape of the error profile that results. Then have to repeat the work for many pixels. currently looking at 5x5 pixels. 

Questions:

  • does shape of error envelope make sense?
  • add trace for eg SOSS SUBSTRIP256 and do calculations for pixels that will receive flux
  • add cross-dispersion profile for flux in orders
  • consider adding wavelength-dependent behaviours. 
5 mins4.TSO JWebbinar

Nestor Espinoza 

Introduction to JWebbinars. These are 2-hour classroom sessions, repeated up to 3 times. Material required is 1-2 presentations, 2-3 worked notebooks. 

For a Webinar date of Sep 15th, the deadline for material would be Sep 5th.

Feedback from the team:

Everett: there definitely is the need from the community for more support using the pipeline. this was the experience from the ERS hack week. 

SK: appreciate that there is a need and it would be really good to host a webbinar for the community but personally don't have the time to commit to it. 

Will be discussed further!




5 mins5. Closing remarks

Update on documentation work:

SK has created JIRA tickets to create the new content and has green light to proceed. Will familiarise myself with the author workflow and contact the otehr WG members with instructions and info to proceed. Soon!







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