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5 mins

1. News & announcements

  • senior staff scientist positions are being kept open until after the AAS
  • Maca Garcia Marin is moving to the JWST MO own 16 Dec
  • New NIRSpec branch manager: no timeline yet
  • Brian Brooks : ETC release coming soon, should take note for PandExo & ExoCTK. Release dat goal is Dec 2nd but could slip a few days. 
  • WASP-43b phase curve observation happening today!
10min2. Status on TSO commissioning papers
  • SW: accepted!
  • LW: in progress. need to come up with a schedule to make sure it gets done. 
  • Loic Albert : going forward with publishing the HAT-P-14b data in the NIRISS SOSS overall paper.
    • ES: agree just including a spectrum isn't really "doing science"; if not doing full retrievals analysis then should be fine.
  • NN: what about the ERO TSO data, can we just take that or is it subject to the ERS code of conduct? There is someone in the ERS team already working on it. 
    • NE: not necessarily subject to the CoC but the ERS team has contributed a lot to the best practices, so is best to work with them and acknowledge those contributions.
    • Using the EROs to study performance is also entirely under our purview
  • accepted!
5min3. TSO Backgrounds discussion Nestor Espinoza 

See paper by Jane Rigby

  • not sure all instruments have studied this in detail yet - hasn't been very high on our radar yet (SK: apart from MIRI!)
  • data from NIRSpec BOTS on Trappist-1c (public data)
    • running tests on how to remove 1/f noise in small subarray
    • background subtraction affects the recovered spectrum
    • would be much easier if we had a dedicated background observation
  • SK MIRI: we have updated our recommendations fro MIRI to include a dedicated background observation, to perform the subtraction more cleanly. analysis done by Achene Dyrek in Paris.
  • NN: should also factor in the SNR of the spectrum in this analysis as this will impact the 1/f noise
  • how dominant is the background at the longer wavelengths? can model it or calculate in ETC?
    • SB: for BOTS it is clearly visible. there is not a lot of structure in it. 
  • EM: when we do TSO for brown dwarfs from the ground. from the ground the background is very high so we always dither. Should dither?
  • NN: when you remove the background, why would you observe a shallower transit?
    • background comes from 1 px in the smallest subarray. so it's hard to do a proper background subtraction. the PSF also changes in size with wavelength so it's variable with wavelength.
  • NN: are we talking about a time-variable background?
    • NE: we didn't see it in commissioning data
  • SK: this is something the instrument teams should be studying - what is the best way of getting the measurement and perform the correction? dithering during an exposure is really not advisable for TSOs. 
    • for MIRI we do plan to reach out to PIs to recommend they add a dedicated background exposure to their observation
  • LA: this should be part of the STScI calibration program to gather data at representative zodiacal locations and can provide templates for correction
  • NIRCam (NN): typically are able to get the background from the data itself. have not looked at background-only data to study profile. Scattered light is a bigger problem.
    • ES: would be good to get some grism data of the zodiacal light. from what we've seen it's smooth and not complicated, but more data would be good. 
  • Who should make these recommendations? TSO WG, instrument teams?

  • Nestor Espinoza papers: all apart from NIRCam LW now ready. we should probably phase out this discussion. Tom Beatty is working on it, we should prob just let him get on with it.
  • Nestor Espinoza contacted by Jeff Mangum, PASP editor - some decided to go for OA, others not, do we want a common approach?
    • MIRI: yes. ESA can chip in the extra money
    • NIRCam: could do it as well. 
    • (maybe check with the lead authors)
  • Sarah Kendrew : technical TSO position will close next week. 
10min2. Cycle 2 updates

ExoCTKNestor Espinoza 

updates to PandExo following ETC update to v2.0

contamination overlap tool not yet validated, apart from for NIRISS. this will be 


SK explains the story of the MIRI gain

Michael Regan extra caveat is that the gain value can't be used to reverse-calculate the number of events; it does allow us to calculate the poisson noise accurately. 

ERS team will be putting out a short tech note/white paper for the community with the top-level performance findings from the WASP-43b data; this is why we want to close the loop on the gain issue to ensure that the information we provide is consistent across the literature.

3. TSO Work schedule

presented in October; at that point was quite "mild". from Jan, we have more work lined up for the WG. 

  1. pipeline enhancements
    1. cosmic ray detection (Nikolay Nikolov): will start work on this post cycle 2 deadline. note that Michael Regan is also working on the code for this step. should coordinate. don't want to see wasted effort. 
      1. we are seeing CRs that are not getting caught. MR: most likely reason is that the gain and read noise reference files are wrong, or the thresholds aren't optimized. 
      2. MR's method is using sigma clipping to get a more accurate calculation of noise in a pixel.
      3. should work together on this or coordinate to ensure everyone is on the same page
    2. reset corrections (Leonardo Ubeda  & Nestor Espinoza )
  2. TSO program & data monitors
    1. Nikolay has a system for HST TSOs that can be used for JWST as well. (trexolist) would make sense to incorporate this into ExoMAST?
    2. Nikolay also has a QL type monitor that can be implemented for JWST TSOs
    3. NE spoke with Mees on JWQL & they are keen to get this implemented
    4. NN doing a lot of this work in his science time, not officially budgeted as functional work or a proper task 
  3. TSO instrumental systematics investigations - want to identify some small tiger teams to take the lead on these issues
    1. causes of flux variations over time
    2. non-linearity correction
    3. spatial scanning: Peter McCullough would know best what the constraints are as he dis work on this for HST. NE will talk to him. 
    4. MRS TSOs: SK will reach out to the team who put in the calibration proposal in cycle 1 to check on the status of the data & what work needs doing on our side. 
5min3. TSO Backgrounds discussion Nestor Espinoza 
  • Presented the issue to the cycle 1 calibration working group and they are happy for us to put in more observations for the cycle 2 cal program
  • Need to define what those programs/observations should look like
  • SK/MIRI: this is an action item for Greg Sloan on our side, SK will work with him
  • NN/NIRCam: would use the full frame data, mask stars to remove the spectra, and then derive a full-frame background image & generate subarray background from that. NN studying how much the transit spectra are affected by background subtraction. do see scattered light along the spectra, this may be a bigger issue for transit spectra than the actual background subtraction. the background spectral shape is such that it subtracts out very well with traditional methods. the scattered light varies more with wavelength. Also within the 10hrs we discussed with Greg, we would only be able to get data for 1 grism & subarray - for more detailed investigations we would need a larger dedicated program. so not quite sure what the right approach is. 
  • SB/NIRSpec: not sure, haven't considered yet.
10min3. Instrument roundtable check-in


Everett Schlawin Nikolay Nikolov Jdocs updates and vacation!

NIRISSlots of good science and data (smile)


phase curve for LTT9779

NIRSpecOSS 8.5 installed yesterday, few fixes for NIRSpec bu tnot NOTSsome transient MSA shorts. first published phase curve on the arxiv yesterday.

MIRI , Jeroen Bouwman show slides from Achene showing the background measurement issue


we have quite a lot going on and interesting findings - let's put us on the agenda next time & SK will present
2 mins4. Closing Remarks

meeting again in 2 weeks