For a sample of 25 dwarf irregular galaxies with distances D ≲ 5 Mpc and measured oxygen abundances, we present results derived from galaxy luminosities at 4.5 μm and stellar masses from near-infrared imaging with IRAC on the Spitzer Space Telescope. We have constructed the appropriate luminosity-metallicity (L-Z) and mass-metallicity (M-Z) relations, and compared these relations with their corresponding relations from the Sloan Digital Sky Survey (SDSS). We obtain the following results. 1. The dispersion in the near-infrared L-Z relation is reduced with respect to the dispersion in the optical L-Z relation, which agrees with expectations for reduced variations of stellar mass-to-light ratios at longer wavelengths compared to optical wavelengths. 2. The dispersion in the optical L-Z relation is similar over approximately 11 mag in optical luminosity. 3. With our constructed M-Z relation, we have extended the SDSS M-Z relation to lower masses by about 2.5 dex in stellar mass. 4. The dispersion in the M-Z relation appears to be comparable over a range of 5.5 dex in stellar mass. © 2007 Springer.
CITATION STYLE
Lee, H., Skillman, E. D., Cannon, J. M., Jackson, D. C., Gehrz, R. D., Polomski, E., & Woodward, C. E. (2007). Spitzer 4.5 μm luminosity-metallicity and mass-metallicity relations for nearby dwarf irregular galaxies. In ESO Astrophysics Symposia (Vol. 2007, pp. 181–185). https://doi.org/10.1007/978-3-540-71173-5_30
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