2025-03-06 NIRCam/DHS TSO Target Selection Meeting

Nestor Espinoza 

Aarynn Carter , Achrene Dyrek 

• Aarynn Carter to present list of "worst targets for transmission".
  
  
  • Took all targets > 0.4 MJupiter transiting exoplanets.
  • Filtered on K-mag and transit depth.
  • Trimmed by transit duration below 5 hours — so good to double check.
  • There's also a colorbar with the estimate on the SNR of transmission at K-magnitude.
  • Blue is "better" for us (bad for transmission) — red is not as good.
  • There's of order ~30 targets
  • He thinks it would be good to select targets that don't saturate on the long wavelength channel.
    
    
• Achrene Dyrek can find the targets that don't saturate on the long wavelength. Everett Schlawin thinks that all the targets shown are below saturation, so we should be safe:
  
  • Everett Schlawin mentions for the smallest subarray at least all the targets shown are below saturation.
  • Aarynn Carter asks whether we do want to go to the smallest subarray.
  • Nestor Espinoza suggests to minimize unknowns and not push these observations to the limit. Idea is to get out of this data the largest amount of information for the "average" target, showcase the mode, check that it works etc — i.e., be safe, not use smallest subarray if possible.
  • Aarynn Carternotes we should push observations to gather all 8 spectra.
  • Achrene Dyrek suggests also a F150+F444w.
  • Nestor Espinoza notes that perhaps going DHS + F322W2+Grism would be a good idea — stay away from CO2, and also allows you to cross compare with, e.g., NIRISS/NIRSpec.
     
• In terms of trimming the target list:
  
  
  • Nestor Espinozasuggests to cut on K-mag to choose a safe subarray, then by transit duration (you don't want anything > 3 hours to have plenty of pre and post-baseline).
  • Aarynn Carternotes to not choose hot targets (to avoid nightside emission, hints of phase curves).
  • Everett Schlawin notes period to be smaller than a ~weekly to help with scheduling.
    • Achrene Dyrek asks what's a good period? Nestor Espinoza suggests of order < 3 days.
  • Nestor Espinoza suggests to pass the final targets through, e.g., PandExo.
  • Aarynn Carter suggests to do some cuts on stellar properties:
    • Stellar activity hopefully minimal.
    • Nestor Espinoza suggests to search for companions on, e.g., Gaia to avoid close blending sources/contaminating sources.
  • Everett Schlawin suggests another nice to have:
    • Check if the targets have another dataset.
    • Nestor Espinoza can help analyzing TESS data for the final target list.
• Definition of next steps to simulate spectra:
  
  
  • Nestor Espinoza suggests to estimate the noise level you would expect on the lightcurves, as well as on the expected transit depth precisions.
  • Munazza Alam notes she has some code that can help with this.
  • Nestor Espinoza suggests this is a good exercise because you'll have to do it to compare against data anyways ---- good to have before hand to see if anything is going OK.

• Schedule for NIRCam/DHS observations/MS implementation.
  
  
  • Achrene Dyrek will keep everyone updated on this. Improtatn for the team to reserve time to help out with analysis, reduction, etc.
  • Definition of timeline for setting up the details of the program
    • Achrene Dyrek will work on this. She believes a month to do a bit of calibration on DHS.
      
      
• Distribution of tasks accross the team.