Towards the Grand Unification of AGNs in Hierarchical Cosmologies Nikos Fanidakis and C.M. Baugh, R.G. Bower, S. Cole, C. Done, C.S. Frenk January 30, 2009

Outline Supermassive black hole (SMBH) growth in hierarchical cosmologies Cosmological black hole (BH) spin evolution Predicting the radio loudness of AGNs Conclusions

Mass, Spin Rotating BHs in Astrophysics Black holes are the simplest objects in the Universe. They can be completely described by just two parameters, the mass and the spin. Black holes are the simplest objects in the Universe. They can be completely described by just two parameters, the mass and the spin.

Supermassive Black Holes in Λ CDM SMBHs reside at the centres of all galaxies with spheroids. Channels of SMBH growth:  Hot gas accretion: quiescent accretion from hot halo.  Cold gas accretion: accretion of gas during galaxy mergers and disk instabilities.  BH binary mergers. The growth of mass affects the evolution of the BH spin.

Supermassive Black Holes in Λ CDM SMBHs reside at the centres of all galaxies with spheroids. Channels of SMBH growth:  Hot gas accretion: quiescent accretion from hot halo.  Cold gas accretion: accretion of gas during galaxy mergers and disk instabilities.  BH binary mergers. The growth of mass affects the evolution of the BH spin.

BH spin change in astrophysical processes BH mergers M 1, S 1 M 2, S 2 L2L2  Binary BHs form during galaxy mergers.  The system hardens due to the emission of gravitational waves – the two members eventually merge.  During the merger the satellite BH transfers its angular momentum and spin to the central BH.  The final remnant is always a rotating BH. BH accretion last stable orbit accretion disk  Gas accreted via an accretion disk transfers its angular momentum at the last stable orbit to the BH: Co-rotating gas – spin up Counter-rotating gas – spin down  The size of the disk is limited by its self-gravity: A single accretion event of M acc gives rise to a series of separated accretion episodes.

Spin Distributions

AGN Jets Image source: Narayan+05 M87 Jet formation: Twisted magnetic lines collimate outflows of plasma. The jet removes energy from the disk/BH. The plasma trapped in the lines accelerates and produces large-scale flows. The jet power increases proportionally to the BH spin: Blandford & Znajek 1977

AGN radio loudness dichotomy AGN radio loudness: Observational facts AGNs can be divided into two classes: – Radio-loud objects (jets dominate radio emission) – Radio-quiet objects (negligible emission from jets) AGNs form two distinct sequences on the L bol –L radio plane: – Upper sequence: objects hosted by giant ellipticals with M SMBH >10 8 M  – Lower sequence: objects hosted mainly by spirals with M SMBH <10 8 M  Spin paradigm: the BH spin is assumed to determine the radio loudness of an AGN Radio-loud objects Radio-quiet objects Data: Sikora et al. 2007

AGNs in GALFORM : modelling the disk/jet Accretion in GALFORM spans a wide range of accretion rates: Note: The geometry of the disk depends on the accretion rate! Accretion in GALFORM spans a wide range of accretion rates: Note: The geometry of the disk depends on the accretion rate! Thin disk ADAF Meier 1999 Remember :

AGN radio loudness: theoretical predictions

Conclusions We have developed a model using GALFORM for explaining the radio loudness of AGNs. Our results seem to reproduce reasonably well with the observational data. In our model the spin and the accretion rate define the radio loudness of an AGN. Future work Radio/X-ray luminosity functions RL/RQ AGN clustering AGN feedback (?)

Quasar LF

Warped accretion disks