The 2MASS Color-Magnitude Diagram of the Center of the Sagittarius Dwarf Galaxy: Photometric Measurements of a Surprisingly High Mean Metallicity

Abstract

We present the Two Micron All Sky Survey (2MASS) (J-K, K) color-magnitude diagram for the region within 1 degree of the center of the Sagittarius dwarf spheroidal galaxy. Using the slope of the red giant branch (RGB), we determine a mean metallicity for the main stellar population of [Fe/H] = -0.5 +/-0.2. The Sagittarius RGB possesses a blue tail that overlaps with the foreground Milky Way giant branch, and suggests that approximately 1/3 of the RGB is more metal-poor than [Fe/H] = -1. Direct comparison to the Large Magellanic Cloud confirms the metal-rich nature of the bulk of the Sagittarius population. Our result is marginally consistent with the even higher metallicities determined from high-resolution spectroscopy.

5 pages, 4 figures, accepted by ApJ Letters, uses emulateapj.sty

References in corpus (2)

• Color Transformations for the 2MASS Second Incremental Data Release
• Mapping the Galactic Halo. V. Sgr dSph Tidal Debris 60 degrees from the Main Body

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• First detection of the RGB-bump in the Sagittarius dSph
• The Cosmological Significance of High-Velocity Cloud Complex H
• The IGIMF and other IMFs in dSphs: the case of Sagittarius
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