2008/09/15 by Barry F. Madore, Violet Mager, Wendy L. Freedman · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Space Science and Extraterrestrial Life #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1088/0004-637x/690/1/389
published as Astrophys.J.690:389-393,2009 · 9 pages, 6 figures; to be published in the Astrophysical Journal
arxiv created 2008/09/15 · openalex publication_date 2008/12/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We introduce a modified detection method for measuring the luminosity of the tip of the red giant branch (TRGB) by introducing the composite magnitude T ≡ I − β[( V − I ) ○ − 1.50], where β is the slope of the tip magnitude as a function of color (or metallicity). The method is specifically designed to account for known systematics due to metallicity. In doing so, this simple transformation does away with arbitrary color selections in measuring the tip, and thereby significantly boosts the population of resolved stars that go into defining the TRGB distance. Moreover, this method coincidentally reduces the impact of reddening on the true modulus as well as its final uncertainty.