Atomic Chemistry in Turbulent Astrophysical Media. Issue Volume 11:Issue A29B(2015) (27th October 2016)

• Record Type: Journal Article
• Authors: Scannapieco, Evan; Gray, William J.; Kasen, Daniel
• Editors: Benvenuti, Piero
• Is Part Of: Proceedings of the International Astronomical Union. Volume 11:Issue A29B(2015)
• Page Start: 731
• Page End: 731
• Publication Date: 2016-10-27
• Subjects: Turbulence, -- ISM: atoms, -- ISM: abundances; Astronomy -- Congresses; Astronomy -- Periodicals; 520
• DOI: 10.1017/S1743921316006566
• Languages: English
• ISSNs: 1743-9213

Abstract

Abstract: We decribe direct numerical simulations of turbulent astrophysical media exposed to the redshift zero metagalactic background. The simulations assume solar composition and explicitly track ionizations, recombinations, and ion-by-ion radiative cooling for hydrogen, helium, carbon, nitrogen, oxygen, neon, sodium, magnesium, silicon, and iron. Each run reaches a global steady state that not only depends on the ionization parameter, U, and mass-weighted average temperature, T MW, but also on the the one-dimensional turbulent velocity dispersion, σ1D . We carry out runs that span a grid of models with U ranging from 0 to 10 −2 and σ1D ranging from 12 to 58 km s −1, and we vary the product of the mean density and the driving scale of the turbulence, nL, which determines the average temperature of the medium, from nL =10 16 to nL =10 20 cm −2 . The turbulent Mach numbers of our simulations vary from M ≈ 0.5 for the lowest velocity dispersions cases to M ≈ 20 for the largest velocity dispersion cases. When M ≲1, turbulent effects are minimal, and the species abundances are reasonably described as those of a uniform photoionized medium at a fixed temperature. On the other hand, when M ≳ 1, dynamical simulations such as the ones carried out here, are required to accurately predict the species abundances. We gather our results into a set of tables, to allow future redshift zero studies of the intergalactic medium to account for turbulent effects. They are available athttp://zofia.sese.asu.edu/~evan/turbspecies/ and will be updated as we increase our parameter study. These results are explained in more detailed in Gray, Scannapieco, & Kasen (2015), and Gray and Scannapieco (2015)