Outliers from the Mass--Metallicity Relation I: A Sample of Metal-Rich Dwarf Galaxies from SDSS

Abstract

We have identified a sample of 41 low-mass high--oxygen abundance outliers from the mass--metallicity relation of star-forming galaxies measured by Tremonti et al (2004). These galaxies, which have 8.6 < [12 + log(O/H)] < 9.3 over a range of -14.4 > M_B > -19.1 and 7.4 < log M_*/M_solar < 10, are surprisingly non-pathological. They have typical specific star formation rates, are fairly isolated and, with few exceptions, have no obvious companions. Morphologically, they are similar to dwarf spheroidal or dwarf elliptical galaxies. We predict that their observed high oxygen abundances are due to relatively low gas masses, concluding that these are transitional dwarf galaxies nearing the end of their star formation activity.

Accepted for publication in ApJ

References in corpus (10)

• The Host Galaxies and Classification of Active Galactic Nuclei
• The Origin of the Galaxy Mass-Metallicity Relation and Implications for Galactic Outflows
• Clues to the Origin of the Mass-Metallicity Relation: Dependence on Star Formation Rate and Galaxy Size
• The Metallicity of Galaxy Disks: Infall versus Outflow
• The origin of dwarf ellipticals in the Virgo cluster
• A Possible Origin of the Mass-Metallicity Relation of Galaxies
• The oxygen abundance in the inner HII regions of M101. Implications for the calibration of strong-line metallicity indicators
• The mass-metallicity relation of interacting galaxies
• Low Resolution Spectral Templates For Galaxies From 0.2 -- 10 microns
• Inclination-Dependent Extinction Effects in Disk Galaxies in the Sloan Digital Sky Survey

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• Mass-metallicity relation of dwarf galaxies and its dependency on time: clues from resolved systems and comparison with massive galaxies
• A New Chemical Evolution Model for Dwarf Spheroidal Galaxies based on Observed Long Star Formation Histories
• Identification of Large Equivalent Width Dusty Galaxies at 4 $<$ z $<$ 6 from Sub-mm Colours
• AVID: Formation and evolution of a coalesced major merger of late-type dwarf galaxies (VCC 479) on the outskirts of the Virgo cluster
• The ionization structure and chemical history in isolated H II regions of dwarf galaxies with IFU I. The Sagittarius Dwarf Irregular Galaxy
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