Cosmic ray removal in MOSFIRE K-band pipeline

[Jingwen Wu]

Dear Nick,

This is Jingwen. I have a question about the MOSFIRE pipeline reduction.
In the outcome K-band image, I notice quite a bit cosmic rays (although there are a few in H band image, too, but not very serious). I didn't see there
is a cosmic ray removal process in the current pipeline (or I don't realize where it is), nor do I find a solution in the MOSFIRE google documents.
It maybe easier to remove these cosmic rays in the pipeline processing, say, when the individual images are combined.

I don't know if anyone has asked these question before, but do you have any routing solution to remove these cosmic rays during reduction? Any why
there are more cosmic rays in K-bank rather than in H band?

Thanks a lot!
Jingwen

[Nick Konidaris]

Jingwen:

I've seen this before when the number of K-band spectra per nod position is less than 5 or so. Is this the case for you? If so, then you might need to run an external CRR code like LACOSMIC or the like.

~n

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[jingwe...@gmail.com]

Hi Nick,

This is true for my case. I have 5 spectra on both mod positions, but one of the scan was bad, so we ignore it, leaving 4 and 5 spectra on each position. So do you suggest always keep > 5 spectra on each position to enable better cosmic ray removal?

I will try LACOSMIC.
Thanks!

Jingwen

[jingwe...@gmail.com]

Hi Nick,

One more question for this cosmic removal issue.
I am trying to use external LACOSMIC code to remove cosmic rays. The code request to be applied after
flat and bias subtraction, but before sky subtraction.
Specific to the mosdrp pipeline (for K_driver), can you suggest where is the best place to apply this LACOSMIC cleaning?

Thanks,
Jingwen

[jingwe...@gmail.com]

Now I simply double the scan numbers in the offset_+/-1.5.txt by copying and pasting the existing good scans, and it does improve the quality of the resulting spectra, with much less cosmic rays left.