Influence of the Void Environment on Chemical Abundances in Dwarf Galaxies and Implications for Connecting Star Formation and Halo Mass

Abstract

We study how the void environment affects galactic chemical evolution by comparing the oxygen and nitrogen abundances of dwarf galaxies in voids with dwarf galaxies in denser regions. Using spectroscopic observations from SDSS DR7, we estimate oxygen, nitrogen, and neon abundances of 889 void dwarf galaxies and 672 dwarf galaxies in denser regions. A substitute for the [OII] 3727 doublet is developed, permitting oxygen abundance estimates of SDSS dwarf galaxies at all redshifts with the Direct Te method. We find that void dwarf galaxies have about the same oxygen abundance and Ne/O ratio, slightly higher neon abundances, and slightly lower nitrogen abundance and N/O ratio than dwarf galaxies in denser environments. We conclude that the void environment has a slight influence on dwarf galaxy chemical evolution. Our mass-N/O relationship shows that the secondary production of nitrogen commences at a lower stellar mass in void dwarf galaxies than in dwarf galaxies in denser environments. Our dwarf galaxy sample demonstrates a strong anti-correlation between the sSFR and N/O ratio, providing evidence that oxygen is produced in higher mass stars than those which synthesize nitrogen. The lower N/O ratios and smaller stellar mass for secondary nitrogen production seen in void dwarf galaxies may indicate both delayed star formation and a dependence of cosmic downsizing on the large-scale environment. A shift toward slightly higher oxygen abundances in void dwarf galaxies could be evidence of larger ratios of dark matter halo mass to stellar mass in voids than in denser regions.

22 pages, 17 figures, published in ApJ - significant revisions resulting from referee comments

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Cited by in corpus (7)

• Updated void catalogs of the SDSS DR7 main sample
• Local and large-scale effects on the astrophysics of void-galaxies
• Metal Abundances and Star-Formation Rates of Emission-Line Galaxies in and around the Bootes Void
• The Stellar Kinematics of Void Dwarf Galaxies Using KCWI
• The influence of the void environment on the ratio of dark matter halo mass to stellar mass in SDSS MaNGA galaxies
• Gas accretion and Ram Pressure Stripping of Haloes in Void Walls
• Leonessa: An Extremely Metal-poor Galaxy Undergoing Secular Chemical Evolution