ACES-CMZ / reduction_ACES

Reduction scripts and tools for ACES
https://worldwidetelescope.org/webclient/?wtml=https://data.rc.ufl.edu/pub/adamginsburg/ACES/mosaics/mosaics.wtml
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Execution Block ID uid://A001/X15a0/X180 Sgr_A_st_al_03_7M #139

Open keflavich opened 2 years ago

keflavich commented 2 years ago

Sgr_A_st_al_03_7M uid://A001/X15a0/X180

Product Links:

Reprocessed Product Links:

d-l-walker commented 2 years ago

I've had a quick look through the weblog for this, and the main thing that stands out is that the automasking failed in the cube imaging. I can't see any glaring issues with the actual data, so I'm not sure what's causing this yet. The most obvious thing is this warning:

Warning! Source Sgr_A_star is an odd-shaped mosaic -- there is no mosaic field at the image phasecenter and imaging is likely to fail. The phasecenter of nearest pointing to the image center is ICRS 17:46:26.4396 -028.28.49.281

It seems like CASA doesn't like the shape of this mosaic, and explicitly warns that imaging may fail. So I guess this is the culprit? Can we get around this with manual imaging/custom imaging parameters?

Other than this I don't see any major issues in the weblog.

snlongmore commented 2 years ago

I mentioned this issue in ALMA Heldesk ticket 19313

keflavich commented 2 years ago

Needs reimaging with the psfphasecenter keyword set to a location within the imaged area.

xinglunju commented 2 years ago

@d-l-walker Dan, you will self-assign this issue and work on the re-imaging, right? Is it ok if I assign it to myself too so that a student use this SB to get some experience of weblog review?

d-l-walker commented 2 years ago

@xinglunju of course, that'd be great!

d-l-walker commented 2 years ago

Small, underwhelming update: I've been trying to re-image this for a while now to fix the issues with the PSF being outside of the mosaic.

Original PL pb-corrected continuum

Screenshot 2022-07-19 at 17 07 11

Reprocessed pb-corrected continuum: note the lack of structure and significant difference in values in the colorbar

Screenshot 2022-07-19 at 17 08 27

xinglunju commented 2 years ago

@d-l-walker I used to find similar issues when imaging large VLA mosaics, and it is the 'gridder' keyword in tclean, standard vs. mosaic (the latter should be used). No sure if it is the same issue in your case...

d-l-walker commented 2 years ago

Hi @xinglunju, thanks for the suggestion. In this case I am already using gridder='mosaic'. In fact, I have tried running the exact tclean command used by the pipeline, leaving every parameter unchanged, yet I still get the same issue.

keflavich commented 2 years ago

@d-l-walker perhaps post a log from the imaging run and we can discuss it on the telecon?

d-l-walker commented 2 years ago

Here's the log from a test I did this morning where I ran the same tclean command as the PL to create a dirty continuum image: https://www.dropbox.com/s/s1m17wna5mal932/casa-20220720-081325.log?dl=0

d-l-walker commented 2 years ago

I've finished re-processing this now. As mentioned in this week's telecon, the problem with the low fluxes was to do with the datacolumn in mstransform. I was copying the commands from the original weblog, where data was selected. I just had to change this to corrected and all was fixed.

This recleaning was to fix the issue with the bad PSF and failed automasking due to the PSF being placed outside of the mosaic as a result of the weird mosaic shape. I tried using the psfphasecenter parameter to do this, but tclean failed no matter what I tried. I've passed this along internally to the appropriate people. The workaround solution I used was to:

This isn't the most efficient solution, but hey, it worked ... I'll update the override tclean commands file soon with the parameters used.

@keflavich I've added all of the output files for the continuum + all SPWs, along with FITS files for the .image & .image.pbcor files in /upload/Sgr_A_st_al_03_7M_reclean/. The destination for transfer is /rawdata/2021.1.00172.L/science_goal.uid___A001_X1590_X30a8/group.uid___A001_X1590_X30a9/member.uid___A001_X15a0_X180/.

Here's a preview of the peak intensity maps for each SPW (16 -> 26). All are scaled to the HNCO (SPW 22, bottom left). Residuals and masks look good. I'm happy with the results, so I've marked this as 'Done'. Screenshot 2022-07-29 at 12 38 30

keflavich commented 2 years ago

I moved the files over.