VERTICAL STRUCTURE OF A SUPERNOVA-DRIVEN TURBULENT, MAGNETIZED INTERSTELLAR MEDIUM

By A. Hill, M. Ryan Joung, M. Mac Low, R. Benjamin, L. Matthew Haffner, Christian Klingenberg, Knut Waagan. 2012

135 citations recorded by the source corpus.

Stellar feedback drives the circulation of matter from the disk to the halo of galaxies. We perform three-dimensional magnetohydrodynamic simulations of a vertical column of the interstellar medium with initial conditions typical of the solar circle in which supernovae drive turbulence and determine the vertical stratification of the medium. The simulations were run using a stable, positivity-preserving scheme for ideal MHD implemented in the FLASH code. We find that the majority (≈90%) of the mass is contained in thermally stable temperature regimes of cold molecular and atomic gas at T < 200 K or warm atomic and ionized gas at 5000 K < T < 104.2 K, with strong peaks in probability distribution functions of temperature in both the cold and warm regimes. The 200–104.2 K gas fills 50%–60% of the volume near the plane, with hotter gas associated with supernova remnants (30%–40%) and cold clouds (<10%) embedded within. At |z| ∼ 1–2 kpc, transition-temperature (105 K) gas accounts for most of the mass and volume, while hot gas dominates at |z| > 3 kpc. The magnetic field in our models has no significant impact on the scale heights of gas in each temperature regime; the magnetic tension force is approximately equal to and opposite the magnetic pressure, so the addition of the field does not significantly affect the vertical support of the gas. The addition of a magnetic field does reduce the fraction of gas in the cold (<200 K) regime with a corresponding increase in the fraction of warm (∼104 K) gas. However, our models lack rotational shear and thus have no large-scale dynamo, which reduces the role of the field in the models compared to reality. The supernovae drive oscillations in the vertical distribution of halo gas, with the period of the oscillations ranging from ≈30 Myr in the T < 200 K gas to ∼100 Myr in the 106 K gas, in line with predictions by Walters & Cox.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/aa00ac87b526b5348baddcca8b021b36a1a246e0

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In Astronomy and Astrophysics

1. Chang-Goo Kim
2. E. Ostriker
3. M. Miller
4. Woong-Tae Kim
5. J. Bregman
6. P. Hopkins
7. T. Naab
8. Mark R. Krumholz

In Instrumentation

1. E. Ostriker
2. Chang-Goo Kim
3. M. Miller
4. J. Bregman
5. Woong-Tae Kim
6. M. McQuinn

Citations in the corpus

• THREE-DIMENSIONAL HYDRODYNAMIC SIMULATIONS OF MULTIPHASE GALACTIC DISKS WITH STAR FORMATION FEEDBACK. I. REGULATION OF STAR FORMATION RATES (2013, background): “Magnetic fields also contribute pressure, but because the magnitude is smaller than turbulent pressure and the magnetic scale height is large, the fractional contribution to offsetting the weight of the neutral ISM is small (OS11; Hill et al. 2012).”
• CONSTRAINING THE MILKY WAY'S HOT GAS HALO WITH O vii AND O viii EMISSION LINES (2014, methodology): “We remove any observations within ≤ 10◦ of the Galactic plane to reduce emission from SNe in the Milky Way’s disk (Norman & Ikeuchi 1989; Joung & Mac Low 2006; Hill et al. 2012).”