Speaker
Description
The extended hot ($T=10^6$ K) gas phase of the circumgalactic medium (CGM) is an essential component for studying the baryon cycle of late-type galaxies, because it could supply the galaxy with gas to sustain star formation and possibly contains many of the 'missing' baryons.
Using a simple semi-analytic model based on hydrostatic equilibrium and the latest eROSITA observations, we evolve the hot CGM gas subject to radiative cooling, photoionization and mechanical heating from a central source. In the absence of mechanical heating, we see that gas at large radii flows inwards at a constant rate, but in the inner kpc it cools rapidly. By including mechanical heating, we estimate the power that is needed to stop this inflow. Our results show that a source that could have created the Fermi bubbles is sufficient to halt the rapid inflow and form a self-regulating cycle with the hot CGM (analogous to cooling flows and AGN feedback in clusters) that keeps it stable for a long time.
If this is indeed the case, direct accretion of gas from the hot CGM will be suppressed and therefore we need another mechanism to sustain the constant star formation in the galaxy. In future work, we therefore focus on the cool phase of the CGM, where we perform ultra high resolution magneto-hydrodynamical simulations to study the evolution of these clouds under various conditions. By comparing the results of these simulations to observations, we can learn where these clouds originate and whether they are able to accrete onto the galaxy and supply enough gas to sustain star formation.
| Talk category | NOVA Network 1 |
|---|---|
| PhD relevance | 2nd |
