The Origin of the Stellar Mass-Stellar Metallicity Relation in the Milky Way Satellites and beyond

Abstract

Observations and semianalytical galaxy formation and evolution models (SAMs) have suggested the existence of a stellar mass-stellar metallicity relation (MZR), which is shown to be universal for different types of galaxies over a large range of stellar masses ($M_{\ast }\sim 10^3$-$10^{11}{M}_{\odot }$) and dark matter (DM) halo masses ($M_{\mathrm{halo}}\sim 10^9$-$10^{15}{h}^{-1}{M}_{\odot }$). In this work, we construct a chemical evolution model to investigate the origin of the MZR, including both the effects of gas inflows and outflows in galaxies. We solve the MZR from the chemical evolution model, by assuming that the cold gas mass ($M_{\mathrm{cold}}$) and the stellar feedback efficiency ($\beta$) follow some power-law scaling relationships with $M_{\ast }$ during the growth of a galaxy, i.e., $M_{\mathrm{cold}}\propto M_{\ast }^{{\alpha }_{\mathrm{gs}}}$ and $\beta \propto M_{\ast }^{{\alpha }_{\beta \mathrm{s}}}$. We use the SAM to obtain these power-law scaling relations, which appear to be roughly universal over a large range of stellar masses for both satellites and central galaxies within a large range of halo masses. The range of the MZRs produced by our models is in a narrow space, which provides support to the universality of the MZRs. The formation of the MZR is a result caused jointly by that the cold gas fraction decreases with increasing $M_{\ast }$ and by that the stellar feedback efficiency decreases with increasing $M_{\ast }$ in the galaxy growth, and the exponent in the MZR is around $-{\alpha }_{\beta \mathrm{s}}$ or $1-{\alpha }_{\mathrm{gs}}$. The MZR represents an ''average'' evolutional track for the stellar metallicity of a galaxy. The comparison of our model with some previous models for the origin of MZRs is also discussed.

22 pages, 9 figures, accepted for publication in the Astrophysical Journal

References in corpus (16)

• A Semi-Analytic Model for the Co-evolution of Galaxies, Black Holes, and Active Galactic Nuclei
• Massloss of galaxies due to a UV-background
• COLD GASS, an IRAM legacy survey of molecular gas in massive galaxies: I. Relations between H2, HI, stellar content and structural properties
• The Origin of the Galaxy Mass-Metallicity Relation and Implications for Galactic Outflows
• Ages and metallicities of early-type galaxies in the SDSS: new insight into the physical origin of the colour-magnitude and the Mg2-sigmaV relations
• Clues to the Origin of the Mass-Metallicity Relation: Dependence on Star Formation Rate and Galaxy Size
• Generating Dark Matter Halo Merger Trees
• The Origin and Evolution of the Mass-Metallicity Relationship for Galaxies: Results from Cosmological N-Body Simulations
• The Metallicity of Galaxy Disks: Infall versus Outflow
• Simulations of Cosmic Chemical Enrichment
• The Cosmic Evolution of Metallicity from the SDSS Fossil Record
• A Possible Origin of the Mass-Metallicity Relation of Galaxies
• Insights on the stellar mass-metallicity relation from the CALIFA survey
• Separate ways: The Mass-Metallicity Relation does not strongly correlate with Star Formation Rate in SDSS-IV MaNGA galaxies
• Probing baryonic processes and gastrophysics in the formation of the Milky Way dwarf satellites: I. metallicity distribution properties
• Is the stellar mass-stellar metallicity relation universal in the Milky Way satellites and beyond?

Cited by in corpus (1)

• Neutron star mergers as the astrophysical site of the r-process in the Milky Way and its satellite galaxies