Speaker
Description
Detection of CO, HCN and H2O lines show that quasar outflows are in molecular form up to a radius of 1-10 kpc. To reach such distances, the molecular gas has to be structured in clumps, able to provide sufficient self-shielding against the strong quasar radiation field. I present numerical simulations for the structure of a molecular clumps exposed to a UV radiation field, featuring radiative transfer coupled with hydrodynamics and an accurate chemistry model, including formation and destruction of molecular hydrogen. Molecular clumps are shown to undergo a violent shock-contraction phase, followed by a stationary phase where the molecules are progressively dissociated and flow away from the edge of the clump. The results show photoevaporation timescales of 0.3 Myr for clumps with mass 103 Msun, compatible with the observed extension of quasar outflows, suggesting that photoevaporation is the main mechanism regulating the size of molecular outflows.
| Affiliation | Scuola Normale Superiore |
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