Astronomy & Astrophysics Seminar: Accretion-driven turbulence in the CGM

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Zoom: https://tau-ac-il.zoom.us/j/87230679135?pwd=Y1duRlArUkJwSnhaaXVscUU0azY3Zz09

Abstract:

Turbulence is a key feature of many astrophysical systems, including the circumgalactic medium (CGM). While CGM turbulence is often attributed to outflows originating in the central galaxy, our research suggests that CGM turbulence is also driven by accretion. Using analytic considerations and hydrodynamical simulations, we show that accretion causes turbulence velocities to converge to the inflow velocity, up to a constant of order unity. This results in two distinct regimes of CGM turbulence: in high-mass halos (>10^12 M⊙) where cooling is slow turbulence is subsonic, similar to turbulence observed in the intracluster medium. In low-mass halos (<10^11 M⊙) where cooling is rapid turbulence is supersonic, similar to giant molecular clouds. These findings suggest that the nature of circumgalactic turbulence changes at the Milky-Way mass scale.

Seminar Organizer: Dr. Jonathan Stern