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Title: Efficiency of Metal Mixing in Dwarf Galaxies

Abstract

Metal mixing plays a critical role in the enrichment of metals in galaxies. The abundance of elements such as Mg, Fe, and Ba in metal-poor stars helps us understand the metal mixing in galaxies. However, the efficiency of metal mixing in galaxies is not yet understood. Here we report a series of N -body/smoothed particle hydrodynamics simulations of dwarf galaxies with different efficiencies of metal mixing using a turbulence-induced mixing model. We show that metal mixing apparently occurs in dwarf galaxies from Mg and Ba abundances. We find that a scaling factor for metal diffusion larger than 0.01 is necessary to reproduce the measured abundances of Ba in dwarf galaxies. This value is consistent with the value expected from turbulence theory and experiments. We also find that the timescale of metal mixing is less than 40 Myr. This timescale is shorter than the typical dynamical times of dwarf galaxies. We demonstrate that the determination of a degree of scatters of Ba abundance by the observation will help us to better constrain the efficiency of metal mixing.

Authors:
 [1];  [2]
  1. Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  2. Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)
Publication Date:
OSTI Identifier:
22654502
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 838; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; DIFFUSION; EFFICIENCY; GALAXIES; HYDRODYNAMICS; METALS; MIXING; PARTICLES; SCALING; SIMULATION; STARS; TURBULENCE

Citation Formats

Hirai, Yutaka, and Saitoh, Takayuki R., E-mail: yutaka.hirai@nao.ac.jp. Efficiency of Metal Mixing in Dwarf Galaxies. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA6799.
Hirai, Yutaka, & Saitoh, Takayuki R., E-mail: yutaka.hirai@nao.ac.jp. Efficiency of Metal Mixing in Dwarf Galaxies. United States. doi:10.3847/2041-8213/AA6799.
Hirai, Yutaka, and Saitoh, Takayuki R., E-mail: yutaka.hirai@nao.ac.jp. Sat . "Efficiency of Metal Mixing in Dwarf Galaxies". United States. doi:10.3847/2041-8213/AA6799.
@article{osti_22654502,
title = {Efficiency of Metal Mixing in Dwarf Galaxies},
author = {Hirai, Yutaka and Saitoh, Takayuki R., E-mail: yutaka.hirai@nao.ac.jp},
abstractNote = {Metal mixing plays a critical role in the enrichment of metals in galaxies. The abundance of elements such as Mg, Fe, and Ba in metal-poor stars helps us understand the metal mixing in galaxies. However, the efficiency of metal mixing in galaxies is not yet understood. Here we report a series of N -body/smoothed particle hydrodynamics simulations of dwarf galaxies with different efficiencies of metal mixing using a turbulence-induced mixing model. We show that metal mixing apparently occurs in dwarf galaxies from Mg and Ba abundances. We find that a scaling factor for metal diffusion larger than 0.01 is necessary to reproduce the measured abundances of Ba in dwarf galaxies. This value is consistent with the value expected from turbulence theory and experiments. We also find that the timescale of metal mixing is less than 40 Myr. This timescale is shorter than the typical dynamical times of dwarf galaxies. We demonstrate that the determination of a degree of scatters of Ba abundance by the observation will help us to better constrain the efficiency of metal mixing.},
doi = {10.3847/2041-8213/AA6799},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 838,
place = {United States},
year = {Sat Apr 01 00:00:00 EDT 2017},
month = {Sat Apr 01 00:00:00 EDT 2017}
}