Abstract
Abstract
Galactic outflows from local starburst galaxies typically exhibit a layered geometry, with cool 104 K flow sheathing a hotter 107 K, cylindrically collimated, X-ray-emitting plasma. Here we argue that winds driven by energy injection in a ring-like geometry can produce this distinctive large-scale multiphase morphology. The ring configuration is motivated by the observation that massive young star clusters are often distributed in a ring at the host galaxy’s inner Lindblad resonance, where larger-scale spiral arm structure terminates. We present parameterized three-dimensional radiative hydrodynamical simulations that follow the emergence and dynamics of energy-driven hot winds from starburst rings. In this letter, we show that the flow shocks on itself within the inner ring hole, maintaining high 107 K temperatures, while flows that emerge from the wind-driving ring unobstructed can undergo rapid bulk cooling down to 104 K, producing a fast hot biconical outflow enclosed by a sheath of cooler nearly comoving material without ram pressure acceleration. The hot flow is collimated along the ring axis, even in the absence of pressure confinement from a galactic disk or magnetic fields. In the early stages of expansion, the emerging wind forms a bubble-like shape reminiscent of the Milky Way’s eROSITA and Fermi bubbles and can reach velocities usually associated with active-galactic-nucleus-driven winds. We discuss the physics of the ring configuration, the conditions for radiative bulk cooling, and the implications for future X-ray observations.
Funder
National Science Foundation
NASA ∣ Science Mission Directorate
Publisher
American Astronomical Society
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
5 articles.
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