Selecting the Best ugrizy Filter for TRGB Distances on the LSST

The question

The Tip of the Red Giant Branch is a standard candle: red giant stars reach a sharp luminosity limit before helium ignition, and that edge in a color-magnitude diagram gives a distance. How cleanly the edge appears depends on which filter you observe through. Rubin Observatory's LSST carries the six-band ugrizy filter set, so the practical question is which of those six resolves the TRGB most reliably.

What I did

• Analyzed simulated LSST survey data to construct TRGB color-magnitude diagrams across a range of stellar ages and metallicities.
• Compared the ugrizy filters against one another on how sharply each recovers the tip under those varying stellar populations.
• Wrote up the results as a research paper and presented them on a poster at the program's symposium.