# Resources related to crowded field photometry

**URL:** <https://www.rubin.community/t/resources-related-to-crowded-field-photometry/4605>\
**Category:** Crowded Fields\
**Tags:** crowded-fields, smwlv\
**Created:** [December 18, 2020, 5:47pm UTC](https://www.rubin.community/t/resources-related-to-crowded-field-photometry/4605 "2020-12-18T17:47:43Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jeffcarlin](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/jeffcarlin/32/491_2.png) [@jeffcarlin](https://www.rubin.community/u/jeffcarlin)\
**Post date:** [December 18, 2020, 5:47pm UTC](https://www.rubin.community/t/resources-related-to-crowded-field-photometry/4605/1 "2020-12-18T17:47:44Z")

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This topic is meant to be a repository for links to useful information regarding crowded field processing, and a catalyst for discussion. For now I will keep it brief, and simply seed this with links to a couple of relevant documents:

[DMTN-129: Crowded Field Photometry in LSST Data Release Production](https://dmtn-129.lsst.io/)  
[DMTN-077: LSST Fall 2017 Crowded Fields Testing](https://dmtn-077.lsst.io/)

> [@Completeness as a function of stellar density](http://www.rubin.community/t/completeness-as-a-function-of-stellar-density/4520):
>
> For those interested in the performance of the deblender on crowded stellar fields, may I draw your attention to section 4.1 of [“The Saga of M81: Global View of a Massive Stellar Halo in Formation”](https://arxiv.org/abs/1910.14672) (2020, ApJ accepted) by Adam Smercina et al., where we use fake sources to measure detection completeness as a function of stellar density. Adam found we get good completeness up to 100 arcmin-2, after which it starts to fall off (see Figure 4 from the paper, reproduced below). This number is certainl…

Please add relevant resources to this list, and conversation to this discussion!

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**Author:** ![TomLoredo](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/tomloredo/32/4306_2.png) [@TomLoredo](https://www.rubin.community/u/TomLoredo)\
**Post date:** [December 19, 2020, 2:07am UTC](https://www.rubin.community/t/resources-related-to-crowded-field-photometry/4605/2 "2020-12-19T02:07:52Z")

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Depending on what kind of crowding and deblending you’re interested in (e.g., point source vs. galaxies/extended, and what order multiplets), the DESC blending working group (BL WG) may be a good resource. A lot of work from various groups gets reported and discussed at the BL WG telecons, and the BL WG web site archives slides and notes on that activity. BL WG also organizes sessions on galaxy deblending at DESC and wider LSST meetings. At least so far, this work is mostly focusing on low-multiplicity blends (at 10-yr depth, many LSST fields will be “crowded” in the low-multiplicity sense), but I would guess some of the methods and insights would be relevant for highly crowded fields. I’d link to their web page, but it’s on DESC’s Confluence site at SLAC, requiring DESC membership to access. Those interested specifically in galaxy deblending might consider joining DESC and the BL WG.

-Tom