SGA questions

I already knew that SGA is going to extend into the new Legacy Survey DR10 grz+i images and I have a few questions about it.

Will SGA go expanding within the plane of our Milky Way? (DECaPS Survey)
For the 2022 release, Is the SGA going for more fainter galaxies and thus extending the SGA in new DECaLS DR10 images?

I don’t think there are any plans to expand into the DECaPS region – DECaPS itself only has point-source photometry there, so there’s not really a catalog to base it on, and the plane just really isn’t a very useful place to do (external) galaxy work.
As for the other parts of your questions, I’ll ask the boss to answer!

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Indeed, I have no plans to extend the SGA into the Galactic plane for the reasons given by @dstn. However, it’s an interesting suggestion and if you have ideas for how to select large galaxies among the ocean of stars, please pass them along!

As for the next version of the SGA (hopefully SGA-2023), my plan is to use the new DECaLS/DR10 footprint in the south and the BASS/MzLS imaging in the north and to improve the homogeneity in terms of surface brightness. The catalog will always, however, be formally limited by angular diameter (currently approximately 20 arcsec) and surface brightness, not flux.

Hopefully this feedback answers your question.


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Thanks Mr. Moustakas! I have another question. Later after a 2023 atlas, is there a way to decrease the limit of the angular diameter and surface brightness to add some more galaxies?

It said that on the future plans.

If we expand the atlas into the DECaPS region, it would be all the galaxies in that region in the HyperLEDA database. In this survey, most of the galaxies are obstructed by stars, gas, or dust in our galaxy, making it exceedingly difficult to tell if so to do what SGA does for it’s atlas in 2020.

Sometimes there is an object in the hyperLEDA database that is not a galaxy such as a nebula or foreground star in our galaxy. These could easily be rejected.


Cheers, C&S