Speaker
Description
The first ALMA observation of the nearby quasar PDS 456 (z=0.184) was designed to obtain the highest resolution map ever taken of the molecular gas in a hyper-luminous quasar. With a bolometric luminosity of 2e47 erg/s (~ Eddington luminosity) it can be regarded as the local counterpart of the quasars shining at z ~ 2, i.e. the peak of quasar luminosity density.
We are able to reveal in unprecedented detail (i.e., 0.2 arsec ~ 600 pc) the distribution of the molecular gas around a very powerful AGN and probe the relationship between nuclear and host galaxy properties at the brightest end of the luminosity function.
The most noticeable result is the discovery of a molecular outflow in PDS 456, which also shows the undisputedly most powerful, persistent, X-ray ultra-fast (0.25c) wind discovered so far. This allows us to get new insights on how multi-phase AGN-driven outflows expand outwards. Interestingly, the CO outflow exhibits a very complex, unusual morphology with a compact, sub-kpc component and a ~3 kpc extended, very diffuse approaching one. Finally, multiple gas-rich companions are visible around ~20 kpc from PDS 456 supporting the merger-driven scenario for high-luminosity quasars.
| Affiliation | INAF-OAR |
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