Galactic Winds and Bubbles from Nuclear Starburst Rings

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.

X-Ray Properties of NGC 253's Starburst-driven Outflow

“…In NGC 253, the super star clusters within the nuclear core are likely arranged in a ring-like geometry (Levy et al 2022). Nguyen & Thompson (2022) recently showed that energy and mass injection in a ring-like geometry naturally produces a biconical outflow, where the hot phase is cylindrically collimated. When we include the effect of nonspherical flow geometry into the wind model (red and blue lines in Figure 6), we find better agreement with the profiles.…”

Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy Distributions

“…This may lead to the γ-ray bubble discovered by Fermi observations in the Milky Way (Su et al 2010). Other possible origins of the γ-ray bubble might be originally contributed by a starburst ring (Nguyen & Thompson 2022) or by a relativistic jet (Guo & Mathews 2012). The present model to the GC should be ).…”

Hidden Gems on a Ring: Infant Massive Clusters and Their Formation Timeline Unveiled by ALMA, HST, and JWST in NGC 3351

“…YMCs as potential drivers of large-scale gas outflows. Central starburst rings are believed to be powerful drivers of multiphase galactic winds and outflows (e.g., Armillotta et al 2019;Nguyen & Thompson 2022), and there are indications of such outflows from NGC 3351ʼs central ring from existing multiwavelength observations. By analyzing Chandra X-ray imaging data, Swartz et al (2006) found evidence of hot gas expanding beyond the starburst ring and likely above the plane of the galaxy.…”