The current record for TRGB distances

This project must be done by individuals.

In our class on the TRGB method, we saw an example of the method being applied to a galaxy in the Virgo cluster; that a distance of about 18 Mpc, equivalent to a distance modulus of about (m - M) = 31. The notes for that day describe how difficult it would be to detect the TRGB in a galaxy at the distance of Coma, which is at a distance modulus of about (m - M) = 35.

Difficult, yes -- but is it simply impossible with our current telescopes? What IS the limit for our current telescopes. We can certainly go a bit farther than the Virgo Cluster, but how much farther?

Your job is to look in the astronomical literature for examples of observations of the TRGB in galaxies more than 18 Mpc away. Can you find any? What is the most distant galaxy for which someone has at least claimed to find evidence for the TRGB in a color-magnitude diagram?

You must provide a list of at least 2 papers published since 2020 in which the authors claim to have detected the TRGB at a distance greater than 20 Mpc. For each paper,

• write down the title, name of first author, name of journal, and year
• provide the name of the galaxy(s) which were studied
• for each galaxy(s), list
  • the galaxy's name
  • the apparent magnitude of the TRGB which was observed
  • the distance of the galaxy, based on the TRGB value

Print out your work on paper, and hand it in.

Copyright © Michael Richmond. This work is licensed under a Creative Commons License.