GALAXY MERGERS AND THE MASS–METALLICITY RELATION: EVIDENCE FOR NUCLEAR METAL DILUTION AND FLATTENED GRADIENTS FROM NUMERICAL SIMULATIONS

By D. Rupke, Lisa J. Kewley, J. Barnes. 2010

148 citations recorded by the source corpus.

Recent results comparing interacting galaxies to the mass–metallicity relation show that their nuclear oxygen abundances are unexpectedly low. We present analysis of N-body/smoothed-particle hydrodynamics numerical simulations of equal-mass mergers that confirm the hypothesis that these underabundances are accounted for by radial inflow of low-metallicity gas from the outskirts of the two merging galaxies. The underabundances arise between first and second pericenters, and the simulated abundance dilution is in good agreement with observations. The simulations further predict that the radial metallicity gradients of the disk galaxies flatten shortly after first passage, due to radial mixing of gas. These predictions will be tested by future observations of the radial metallicity distributions in interacting galaxies.

View Paper: https://www.semanticscholar.org/paper/9eaf6bc01a3496213e796a2752bfe9d3f1a3fee4

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1. P. Hopkins
2. Lisa J. Kewley
3. R. Maiolino
4. R. Dav'e
5. Sara L. Ellison
6. P. Torrey
7. R. Somerville
8. L. Hernquist

Citations in the corpus

• THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). I. SURVEY OVERVIEW AND FIRST DATA RELEASE (2015, background): “Gradients measured from spatially resolved emission line diagnostics have provided significant insight into the assembly process at z = 0 (e.g., Vila-Costas & Edmunds 1992; Rupke et al. 2010; Bresolin et al. 2012).”
• A characteristic oxygen abundance gradient in galaxy disks unveiled with CALIFA (2013, background): “For a spiral galaxy with a pre-existing metallicity gradient, gas inflow flattens the gradient by diluting the higher abundance gas in the central regions with the lower abundance gas from the outer parts (Rupke et al. 2010a,b; Kewley et al. 2010).”
• GALAXY-WIDE SHOCKS IN LATE-MERGER STAGE LUMINOUS INFRARED GALAXIES (2011, methodology): “Spectral Fitting We analyzed every spectrum using an automated fitting routine written in IDL, UHSPECFIT, which is based on the code created by Jabran Zahid et al. (2010) and is also employed by and described in Rupke et al. (2010b) and Rich et al. (2010).”
• Galaxy pairs in the Sloan Digital Sky Survey – V. Tracing changes in star formation rate and metallicity out to separations of 80 kpc (2012, background): “This gas then falls towards the nucleus of the galaxy, efficiently funnelled by the bar instabilities (Barnes & Hernquist 1996; Mihos & Hernquist 1996; Cox et al. 2006; Di Matteo et al. 2007; Montuori et al. 2010; Rupke et al. 2010a; Torrey et al. 2012).”
• Metallicity gradients in disks - Do galaxies form inside-out? (2012, methodology): “Our work aims to fill an important gap in the field, by complementing orbital parameter studies (e.g. Rupke et al. 2010a; Perez et al. 2011), systematic sub-grid physics parameter studies (e.g. Wiersma et al. 2011), and detailed dissections of individual systems (e.g. Rahimi et al. 2011; Zolotov et…”
• Constraining sub-grid physics with high-redshift spatially-resolved metallicity distributions (2013, background): “…high-redshift lensed systems (Yuan et al. 2011; Jones et al. 2013), intermediate-redshift galaxies from MASSIV (Queyrel et al. 2012), local discs (Rupke et al. 2010), and the Milky Way (Maciel et al. 2003; Stanghellini & Haywood 2010). results in essentially flat gradients at high-redshift, with…”
• Metallicity gradients in local field star-forming galaxies: insights on inflows, outflows, and the coevolution of gas, stars and metals (2015, methodology): “Disk galaxies in the local Universe universally exhibit negative metallicity gradients, i.e., the centre of a galaxy has a higher metallici y than the outskirts (e.g.,Zaritsky et al. 1994; Moustakas et al. 2010; Rupke et al. 2010b; Sánchez et al. 2014, and references therein).”
• METALLICITY GRADIENTS AND GAS FLOWS IN GALAXY PAIRS (2010, methodology): “In Rupke et al. (2010a), we used Nbody/SPH simulations to investigate the theoretical relationship between metallicity gradients and galaxy major mergers.”
• GAS-PHASE OXYGEN GRADIENTS IN STRONGLY INTERACTING GALAXIES. I. EARLY-STAGE INTERACTIONS (2010, methodology): “A future paper will present similar data on galaxies in the later stages of merging (Rupke et al. 2010, in prep.).”
• De re metallica: the cosmic chemical evolution of galaxies (2018, background): “35) (Rupke et al., 2010b; Rich et al., 2012b; Torres-Flores et al., 2014b).”
• THE METALLICITY EVOLUTION OF INTERACTING GALAXIES (2011, background): “In fact, dynamical metallicity given by our simulation with instantaneous gas recycling (see the black line in the center panel of Figure 9) is very similar to the results of Rupke et al. (2010a).”
• THEORETICAL EVOLUTION OF OPTICAL STRONG LINES ACROSS COSMIC TIME (2013, background): “Flat metallicity gradients can be produced by large-scale gas flows triggered by galaxy interactions (Kewley et al. 2006a, 2010; Rupke et al. 2010b; Rich et al. 2012).”