Webb Office Hours Session 20:  December 12, 2024

Q&A's: 

Q1: Where are the Webb Office Hours procedures and guidelines?

A1: Webb Office Hours. Type your question into the WebEx chat. We will asynchronously copy questions from the chat to this main page and work through them as a group.  If you have images to share please give WebEx permission to share your screen (you may need to log out and log back in again to enable this feature.)

Q2:  My MIRI imaging program contains a lot of saturated pixels.  Is there a way to recover these? 

A2: Unfortunately, the pixels you would like to recover have saturated in less than one group. There is no way to recover from that; with no unsaturated groups it's not possible to estimate a slope.  

Q3: I have warm pixels in my MIRI MRS data and am trying to run the pixel correction in Spec3 pipeline, but am still running into problems.  What is the best way to do this? 

A3: While many warm pixels are caught by the outlier detection step in the calwebb_spec3 pipeline prior to combination of the data into final dither-combined 3-D data cubes, some bright pixels nonetheless make it through into the cubes. 
There is a now an option for bad pixel self-calibration in spec2.  When you turn on bad pixel self-calibration, all exposures on a given detector are used to find and flag bad pixels that may have been missed by the bad pixel mask. This works best when dedicated background observations are included (if you have an extended source with no dedicated background it will not work).  Please see this workbook: https://github.com/spacetelescope/jwst-pipeline-notebooks/blob/main/notebooks/MIRI/MRS/JWPipeNB-MIRI-MRS.ipynb
Please try out this step and see what your results are.  

Q4:  My NIRSpec data has an imprint that I'm trying to remove, what is the best way to do this? 

A4:  You can download the association file from mast and then feed it into the pipeline for help tackling the issue. 

Q5: I have a few questions about noise in MIRI-MRS spectroscopy.  I am working on several projects which are doing deep observations of faint sources and there is noise that seems to have structure in spectral and spatial coordinates even after pixel-based background subtraction.  I am wondering about strategies to reduce this noise.

A5: Yes, this is very hard. The cosmic ray weather can make or break this. The pipeline has multiple options for sky subtraction, if its done in calwebb_spec3 stage works well, it may create systematic issues, so sometimes doing it in  calwebb_spec 2 works better.  However here the noise will likely be worse because you will have more artifacts and is the most susceptible to problems with cosmic ray showers.   
What do your raw 2d files look like? See what is going on there to help you better decide how to proceed. If there are lots of cosmic rays it will be even harder.  Try turning on the find_showers step and see if it helps (in this notebook: https://github.com/spacetelescope/jwst-pipeline-notebooks/blob/main/notebooks/MIRI/MRS/JWPipeNB-MIRI-MRS.ipynb) 

Q6: I'm trying to stitch together some data and want to understand cross calibration between NIRSpec IFU and MIRI MRS. I see consistency in the MIRI data, but there inconsistencies in the NIRSpec data. How can I correct this? 

A6: Please send in an example of your issues into the Help Desk and we will have our cross-instrument calibration group look more closely into this. 

Q7: 

A7: