Galactic r-process enrichment by neutron star mergers in cosmological simulations of a Milky Way-mass galaxy

By F. V. D. Voort, E. Quataert, P. Hopkins, D. Keres̆, C. Faucher-Giguére. 2014

143 citations recorded by the source corpus.

We quantify the stellar abundances of neutron-rich r-process nuclei in cosmological zoom-in simulations of a Milky Way-mass galaxy from the Feedback In Realistic Environments project. The galaxy is enriched with r-process elements by binary neutron star (NS) mergers and with iron and other metals by supernovae. These calculations include key hydrodynamic mixing processes not present in standard semi-analytic chemical evolution models, such as galactic winds and hydrodynamic flows associated with structure formation. We explore a range of models for the rate and delay time of NS mergers, intended to roughly bracket the wide range of models consistent with current observational constraints. We show that NS mergers can produce [r-process/Fe] abundance ratios and scatter that appear reasonably consistent with observational constraints. At low metallicity, [Fe/H] ≾ −2, we predict there is a wide range of stellar r-process abundance ratios, with both supersolar and subsolar abundances. Low metallicity stars or stars that are outliers in their r-process abundance ratios are, on average, formed at high redshift and located at large galactocentric radius. Because NS mergers are rare, our results are not fully converged with respect to resolution, particularly at low metallicity. However, the uncertain rate and delay time distribution of NS mergers introduce an uncertainty in the r-process abundances comparable to that due to finite numerical resolution. Overall, our results are consistent with NS mergers being the source of most of the r-process nuclei in the Universe.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b152f02f7594c003776c45f96a5fad9fae2dfbe9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

The Origin of r-process Elements in the Milky Way (2017, methodology): “…of numerical approaches from one-zone models to cosmological hydrodynamic simulations (Matteucci et al. 2014; Cescutti et al. 2015; Hirai et al. 2015; Ishimaru et al. 2015; Shen et al. 2015; Wehmeyer et al. 2015; Komiya & Shigeyama 2016, see also van de Voort et al. 2015 and Naiman et al. 2017).”
FIRE-2 simulations: physics versus numerics in galaxy formation (2017, background): “…Sparre et al. 2017; Feldmann et al. 2016); metallicities and metal abundance ratios in both “standard” and r-process elements (Ma et al. 2016a; van de Voort et al. 2015); detailed morphological and kinematic structure of thin and thick disks (Ma et al. 2017b); rotation curves and morphologies of…”
First results from the IllustrisTNG simulations: a tale of two elements - chemical evolution of magnesium and europium (2017, methodology): “As noted in Piran et al. (2014) and van de Voort et al. (2015), while typical values for the ISM lead to a cooling mass of Mmix ≈ 103.5 − 104 M (Montes et al. 2016), assumptions about the local conditions of the gas, in particular with respect to vISM, can vary greatly in the presence of intense…”
THE r-PROCESS NUCLEOSYNTHESIS IN THE VARIOUS JET-LIKE EXPLOSIONS OF MAGNETOROTATIONAL CORE-COLLAPSE SUPERNOVAE (2015, background): “…chemical evolution have revisited this problem in different models with several r-process sources including NS-mergers, NDWs, and MHD-SNe (e.g., Cescutti & Chiappini 2014; Matteucci et al. 2014; Tsujimoto & Shigeyama 2014a,b; van de Voort et al. 2015, B. Wehmeyer et al., 2015, in preparation).”
The impact of individual nuclear properties on $r$-process nucleosynthesis (2015, background): “Finally, the idea that neutron star mergers could be the origin of all r-process elements seems to fit some new numerical galactic simulations [149, 150], though the delay time for mergers to begin contributing to galactic nucleosynthesis is still uncertain [34].”
NEUTRINO-DRIVEN WINDS IN THE AFTERMATH OF A NEUTRON STAR MERGER: NUCLEOSYNTHESIS AND ELECTROMAGNETIC TRANSIENTS (2015, background): “…source of r-process in the early galaxy, more recent studies are either more optimistic about their role (Matteucci et al. 2014) or actually favor them over supernovae as major production site, see for example the recent hydrodynamical studies of Shen et al. (2015) and van de Voort et al. (2015).”
Origin of the heaviest elements: The rapid neutron-capture process (2019, background): “high resolution run of van de Voort et al. (2015) as well as recent further investigations (van de Voort et al.”
DETAILED CHEMICAL ABUNDANCES IN THE r-PROCESS-RICH ULTRA-FAINT DWARF GALAXY RETICULUM 2 (2016, background): “…Argast et al. 2004; Matteucci et al. 2014; Cescutti et al. 2015), within dwarf spheroidal (dSph) galaxies (Tsujimoto & Shigeyama 2014), or within cosmologically-motivated galaxy merger models and simulations (Komiya et al. 2014; Ishimaru et al. 2015; Shen et al. 2015; van de Voort et al. 2015).”
Production of the entire range of r-process nuclides by black hole accretion disc outflows from neutron star mergers (2016, methodology): “…previous arguments against mergers being dominant r-process sites based on Galactic chemical evolution and the observed prompt enrichment of r-process nuclei in metal poor stars (e.g. Argast et al. 2004) have been challenged (e.g., van de Voort et al. 2015; Shen et al. 2015; Hirai et al. 2015).”
The structure and dynamical evolution of the stellar disc of a simulated Milky Way-mass galaxy (2016, methodology): “This simulation is originally presented in Hopkins et al. (2014) and has been thoroughly studied in other work (van de Voort et al. 2015; Faucher-Giguère et al. 2015; Muratov et al. 2015; Ma et al. 2016; El-Badry et al. 2016).”
Dynamical Mass Ejection from Binary Neutron Star Mergers (2016, background): “In more recent models of galactic chemical evolution performed within cosmological zoom-in simulations (Shen et al. 2015; van de Voort et al. 2015) or by accounting for accretion of sub-halos into the Milky Way halo (Ishimaru et al. 2015) these problems seem to be mitigated and better agreement…”
Stellar and Quasar Feedback in Concert: Effects on AGN Accretion, Obscuration, and Outflows (2015, methodology): “In a series of papers (Hopkins et al. 2014; Muratov et al. 2015; Oñorbe et al. 2015; van de Voort et al. 2015; Ma et al. 2015b,a; Faucher-Giguere et al. 2015), we showed that, on galactic scales, these models produce a quasi-steady ISM in which molecular clouds form and disperse rapidly, with phase…”