SIMULATIONS OF DISK GALAXIES WITH COSMIC RAY DRIVEN GALACTIC WINDS

By C. Booth, O. Agertz, Andrey V. Kravtsov, Nickolay Y. Gnedin. 2013

133 citations recorded by the source corpus.

We present results from high-resolution hydrodynamic simulations of isolated Small Magellanic Cloud (SMC)- and Milky-Way-sized galaxies that include a model for feedback from galactic cosmic rays (CRs). We find that CRs are naturally able to drive winds with mass loading factors of up to ∼10 in dwarf systems. The scaling of the mass loading factor with circular velocity between the two simulated systems is consistent with required to reproduce the faint end of the galaxy luminosity function. In addition, simulations with CR feedback reproduce both the normalization and the slope of the observed trend of wind velocity with galaxy circular velocity. We find that winds in simulations with CR feedback exhibit qualitatively different properties compared to supernova-driven winds, where most of acceleration happens violently in situ near star forming sites. The CR-driven winds are accelerated gently by the large-scale pressure gradient established by CRs diffusing from the star-forming galaxy disk out into the halo. The CR-driven winds also exhibit much cooler temperatures and, in the SMC-sized system, warm (T ∼ 104 K) gas dominates the outflow. The prevalence of warm gas in such outflows may provide a clue as to the origin of ubiquitous warm gas in the gaseous halos of galaxies detected via absorption lines in quasar spectra.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/47b0252d9acfa4265f5285a4f299bfcbbd2488b9

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Citations in the corpus

ON THE INTERPLAY BETWEEN STAR FORMATION AND FEEDBACK IN GALAXY FORMATION SIMULATIONS (2014, background): “…by Teyssier et al. (2013), and can be viewed as accounting for the effective pressure from a multiphase medium, where local unresolved pockets of hot gas exert work on the surrounding cold phase, or a placeholder for other sources of energy, such as turbulence and cosmic rays (Booth et al. 2013).”
Neutral hydrogen in galaxy haloes at the peak of the cosmic star formation history (2014, background): “…point to missing physics in our current calculations, such as magnetic fields and cosmic rays, which could play a significant role in injecting cool gas into halos (e.g., Booth et al. 2013; Salem & Bryan 2014) and in maintaining the integrity of cool gas in galactic winds (McCourt et al. 2014).”
The impact of star formation feedback on the circumgalactic medium (2016, background): “Magnetic fields, anisotropic conduction, and cosmic rays may also play an important role in the evolution and phase structure of the CGM (e.g., Booth et al. 2013; McCourt et al. 2015).”
How Stellar Feedback Simultaneously Regulates Star Formation and Drives Outflows (2015, background): “Then, other sources ofacceleration, such as supernovae from runaway OB stars (e.g.Li et al. 2015) or cosmic rays (Uhlig et al. 2012; Booth et al. 2013; Hanasz et al. 2013; Salem & Bryan 2014; Salem et al. 2014; Girichidis et al. 2016), may provide the remaining momentum deposition necessary to…”
The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations (2015, background): “…since there are sources of energy feedback other than Type II SNe, and indeed such sources are often invoked in simulations of galaxy formation, for example stellar winds and radiation pressure (Stinson et al. 2013; Hopkins et al. 2014) or cosmic rays (Jubelgas et al. 2008; Booth et al. 2013).”