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spacetelescope / jwst

Python library for science observations from the James Webb Space Telescope
https://jwst-pipeline.readthedocs.io/en/latest/
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Build 7.3 extract1d for MIRI-MRS data yields extremely large flux densities #4229

Closed stscijgbot closed 4 years ago

stscijgbot commented 5 years ago

Issue JP-1123 was created by Beth Sargent:

As noted in JP-994, in pipeline Build 7.3, when using extract1d to extract the spectrum of a point source simulated for MIRI-MRS, the spectrum obtained from the extract1d step was a factor of around 10^10 too high, compared to an aperture-photometry-based extraction performed slice-by-slice in the cubes generated from the cube_build step.

Discussion with Phil Hodge revealed a bug yielding most, if not all of this 10^10 discrepancy, having to do with the way pixel solid angles are computed for an observation very near Right Ascension = 0.

stscijgbot commented 4 years ago

Comment by Jonathan Eisenhamer: [~sargent] Can you retest this?

stscijgbot commented 4 years ago

Comment by Beth Sargent: I still get the few times 10^10 discrepancy for simulated data when the RA=0.  I did try simulated data where I changed the positional keywords to be away from RA=0, and for that data, the extract1d spectrum and my own extraction of the data agree to within 10^-10.

I am using version 0.14.2 of the DMS pipeline.

philhodge commented 4 years ago

Beth, you need to use version 0.14.3 to get extract_1d that has been updated to work with the current version of photom.

stscijgbot commented 4 years ago

Comment by David Law: This ticket is related to https://jira.stsci.edu/browse/JP-1295 (MRS extract_1d testing); further development/testing has been happening on that ticket.

stscijgbot commented 4 years ago

Comment by Misty Cracraft: Ticket can be closed (per David Law) with the test report in JP-1331.