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Agenda

  • News & Announcements (all)
  • Previous and Upcoming TSO Observations (Espinoza)
  • Status on Jira Tickets (all)
  • NIRSS/SOSS Backgrounds (Baines)
  • Closing Remarks (all)

Discussion items

TimeItemWhoNotes

10min

News & AnnouncementsMunazza




Previous TSO ObservationsEspinoza
  • Lots of interesting observations happened. Some highlights:

    • Observations of TOI-3884 b completed apparently successfully (4 observations, 2 NIRISS/SOSS and 2 NIRSpec/BOTS).
    • Phase curve of WASP-76b was apparently successful.

Status on Jira TicketsAll


  • Munazza Alam gives updates on NIRSpec/BOTS

    • There's going to be an updated Notebook on the NIRSpec/PRISM Jupyter notebook. Leonardo Ubeda has been working on this, and Munazza Alam is jumping on finishing this up. Target is going to be Kepler-51 b.

      • Nestor Espinoza asks whether this is a problem given the Kepler-51 b spectrum has not been published yet. Suggests to reach to the Mission Office to check about this.
        Suggests perhaps WASP-39b could be used? Munazza Alam will check this.

    • Munazza Alam is working the TR on linearity analysis results — will present results on this on January 5th.
  • Nestor Espinoza updates on NIRISS/SOSS:
    • He mentions that some work might get started on Multistripe for this mode
      Jira
      serverSTScI JIRA
      serverIdaac911eb-9c55-3f14-8368-77b436fb6dc2
      keyJSOCINT-852
      .

    • Mentions Aarynn Carter is working on producing a TR for the ramp-fitting work.
       
  • Achrene Dyrek introduces updates on NIRCam:
    • Recieved flux calibration data from NIRCam/DHS — Achrene Dyrek looked at the data, it looks good. All the data for all filters. Everett Schlawin also looked at this data and looks good.

    • Achrene Dyrek also re-bumps discussion on reference pixels. There's a discussion on zero or a few pixels.
    • Nestor Espinoza updates on NIRcam/DHS spectral contamination. Achrene Dyrek created a map of where the maps.
  • Hannah Diamond-Lowe updates that on the MIRI side there's some tickets already on Jira (https://jira.stsci.edu/secure/RapidBoard.jspa?rapidView=962&view=detail&selectedIssue=JWSTTSO-13#):
    • A lot of these are currently focused on MIRI imaging, but a bunch of them could be copied to MIRI/LRS. This requires for Hannah Diamond-Lowe to talk with Ian Wong to see which ones would make sense.

    • The more "nebulous" — but also important! — of the tickets are:
      • Investigating systematics within MIRI TSOs:
        Jira
        serverSTScI JIRA
        serverIdaac911eb-9c55-3f14-8368-77b436fb6dc2
        keyJWSTTSO-29
      • Best-practices on ramp-fitting within groups:
        Jira
        serverSTScI JIRA
        serverIdaac911eb-9c55-3f14-8368-77b436fb6dc2
        keyJWSTTSO-30
      • Testing flat-fielding on TSOs (currently not flat fielded, wants to study if this helps or hurts MIRI TSOs):
        Jira
        serverSTScI JIRA
        serverIdaac911eb-9c55-3f14-8368-77b436fb6dc2
        keyJWSTTSO-32



NIRISS/SOSS BackgroundsBaines


  • Presentation is one he gave prior to the holidays on the work going on on SOSS Zodiacal Sky Background:
    • Problem is that the GR700XD disperses the background. This background has two components: a faint one "to the left" and a bright one "to the right" — what drives this shape? Does it change from observation-to-observation?

    • First, simulating the background: there was IDL code from Loic Albert (UdeM) that Tyler converted to Python to see how the background shape compares to actual data:

      • Nice thing is that this allows you to divide the background components from each spectral order, and see which dominates. Orders 0, 1 and 2 dominate — Order 3 is much less signal throughput.

      • One thing that wasn't really reproduced by simulations is the "tilt" of the actual background (left simulated, right observations):

        Image Added

    • Next, Tyler Baines introduces the fact that there's a SOSS Sky Background Calibration program (PIDs 1541, 4479, 6658), to see how the background changes with pointing, day of year, etc. 

      • For each observation, there's 10 dithers to "remove" the sources from the observations to only get the background.

      • The analysis of this data ends on an actual empirical background image for each observation. In the image below, you see the dithers and sources — and on the right the final empirical background:

        Image Added

        The upper quadrant is the one actually used by SUBSTRIP256/96 in typical NIRISS/SOSS observations.

      • Background level is changing from observation to observation! It strongly depends on ecliptic latitude (brighter the closer you are to the ecliptic). There's also shape variations, in particular on the "bright end" of the background. This is expected from current Zodiacal Light models: most variations as a function of wavelength on the Zodiacal background as a function of ecliptic latitude happen at wavelengths above 3 um, which is what Order 0 samples (orders 1, 2 and 3 all sample wavelengths < 3 um). 

      • Currently working on implementing these background templates on a step on the pipeline that can remove this from observations.

        • There's discussion right now on using scaled versus unscaled backgrounds to correct images.

      • It seems one can get down to flux count residuals on images of down to ~2-3% using the templates/methodologies developed by his work. 
    • Questions: 

      •  Everett Schlawin asks whether the shape of the background changes as a function of time. Tyler Baines still working on this; it might change slightly as a function of the pupil wheel position (PWCPOS).


).Closing remarks

Action items