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:I have some MIR MRS data of a bright galaxy with an extended gas tail. I'd like to do 3D continuum subtraction, have tried Cubeviz using the entire FOV to model it. All the continuum comes from the galaxy, and Ive tried to model it with an aperture around the galaxy. When I subtract it it leaves a residual. Is there a way to subtract this in a cleaner way?
A2: The solution would be to feather the subtraction between the central region and the rest, by tapering the continuum from the peak to the edge. There is no specific tool to do this in Cubeviz, so it would require a custom analysis. There should be a smooth transition rather than a step function. For example, multiply (don't convolve) your continuum cube by a Gaussian taper or linear taper function that peaks in the center and goes to a low value or zero at the edge. I would also make the radius of the nonzero continuum larger to allow a more gradual transition. It may also help to scale the continuum cube by a value <1 (like 0.99) to reduce the amount of subtraction at the edge. Finally, subtract the continuum cube from the data.
Q3: For my MRS Channel 1 and 2 cubes (6 pointing mosaic), when I collapse them, it looks like one of the pointings seems to be brighter than the rest. Is there an issue or possible mitigation? Is a pretty bright cluster galaxy. The brighter regions is making it hard to model
A3: It could be cross-artifact residuals, there is a step in the pipeline that largely corrects for it, largely in channel1, but medianing across many wavelengths will highlight any residuals. The step is turned on by default. The fact that its only on one tile may be because of the source location in the FOV. There are no tunable parameters on the cross-artifact correction. The increase of signal as a function of wavelength will depend on the target SED. If the Spilker+ 'stripe' correction code has been useful for other analysis in this field it may be useful here too.
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