On Extending the Mass‐Metallicity Relation of Galaxies by 2.5 Decades in Stellar Mass

Abstract

We report 4.5 µm luminosities for 27 nearby (D 5 Mpc) dwarf irregular galaxies measured with the Spitzer Infrared Array Camera. We have constructed the 4.5 µm luminosity-metallicity (L-Z) relation for 25 dwarf galaxies with secure distance and interstellar medium oxygen abundance measurements. The 4.5 µm L-Z relation is 12+log(O/H) = (5.78 ± 0.21) + (−0.122 ± 0.012) M [4.5] , where M [4.5] is the absolute magnitude at 4.5 µm. The dispersion in the near-infrared L-Z relation is smaller than the corresponding dispersion in the optical L-Z relation. The subsequently derived stellar mass-metallicity (M * -Z) relation is 12+log(O/H) = (5.65 ± 0.23) + (0.298 ± 0.030) log M * , and extends the SDSS M * -Z relation to lower mass by about 2.5 dex. We find that the dispersion in the M * -Z relation is similar over five orders of magnitude in stellar mass, and that the relationship between stellar mass and interstellar medium metallicity is similarly tight from high-mass to low-mass systems. We find a larger scatter at low mass in the relation between effective yield and total baryonic mass. In fact, there are a few dwarf galaxies with large yields, which is difficult to explain if galactic winds are ubiquitous in dwarf galaxies. The low scatter in the L-Z and M * -Z relationships are difficult to understand if galactic superwinds or blowout are responsible for the low metallicities at low mass or luminosity. Naively, one would expect an ever increasing scatter at lower masses, which is not observed.

On the universality of luminosity–metallicity and mass–metallicity relations for compact star-forming galaxies at redshifts 0 < z < 3

“…The mass-metallicity relation by Tremonti et al (2004) is often used as a benchmark for comparisons with similar relations obtained for low-z and high-z galaxies (e.g. Lee et al 2006;Maiolino et al 2008;Amorín et al 2010;Manucci et al 2010;Maier et al 2014;Steidel et al 2014;Zahid et al 2011Zahid et al , 2012Zahid et al , 2013Zahid et al , 2014a. However, we note that Tremonti et al (2004) selected all star-forming galaxies, including galaxies with low-excitation H ii regions, while only galaxies with high-excitation H ii regions are present in high-z samples.…”

In-N-Out: The Gas Cycle From Dwarfs to Spiral Galaxies

“…Here we update that analysis to verify our sample of simulated galaxies with the current ISM model and star formation and feedback parameters. Figure 6 shows our simulated galaxies in relation to the observed redshift zero mass-metallicity relationship from Lee et al (2006), Tremonti et al (2004), and Andrews & Martini (2013). 12 The Tremonti et al (2004) metallicity data were lowered by 0.26 dex in order to account for the offset in the metallicity calibration, as noted by Erb et al (2006).…”

“…12 The Tremonti et al (2004) metallicity data were lowered by 0.26 dex in order to account for the offset in the metallicity calibration, as noted by Erb et al (2006). Following Lee et al (2006), stellar masses for the simulations are calculated from the K-and B-band magnitudes. Gas particle oxygen abundances are weighted by the particle's star formation rate (i.e., probability of star formation) to mimic the measurement of metallicities in star-forming regions for observed galaxies.…”

“…12 Note that the method used in Andrews & Martini (2013) differs from that of the other two observed samples. In Andrews & Martini (2013), the direct method was used to measure the metallicity from stacked spectra of SDSS galaxies, whereas in Lee et al (2006) and Tremonti et al (2004) metallicities were measured from the flux ratios of strong lines for individual galaxies. , which is in good agreement with the observed galaxies over that wide range of masses.…”

Metal flows of the circumgalactic medium, and the metal budget in galactic haloes

“…Gallazzi et al 2005;Kirby et al 2013), and metals in the gas phase of the interstellar medium (ISM) (e.g. Tremonti et al 2004; Lee et al 2006). We re-E-mail:amuratov@ucsd.edu † E-mail:dkeres@physics.ucsd.edu fer to both of these relations as MZR, and will specify if stellar or gas phase metallicity is discussed explicitly.…”