Spin paradigm: is the black hole spin related with galaxy morphology?

C. DEL P. LAGOS, S.A. CORA, N.D. PADILLA

La Plata

Otro; First La Plata International School on Astronomy and Geophysics: Compact Objects and their Emission; 2008

We present a study of the revised version of the "spin paradigm" by Sikora & Lasota (2007) which follows the conjecture that the observedAGN-radioloudness bimodality can be explained by a morphology-relatedbimodality of the distribution of black-hole (BH) spins in the centres of galaxies: central BHs in giant elliptical galaxies may have (on average) much larger spins than BHs in disk galaxies. We usea combination of a cosmological N-body simulation of the concordance Lambda cold dark matter (Lambda CDM) paradigm and a semi-analytic model of galaxy formation (Lagos, Cora & Padilla 2008). This new semi-analitic model (SAG hereafter) takes into account Active Galactic Nuclei (AGN) associated with the presence of super massive BHs (SMBH), assumedto grow via (i) gas accretion during merger-driven starbursts and mergers with other BHs, (ii) accretion during starbursts triggered by disk instabilities, and (iii) accretion of cold gas from quasi-hydrostatically cooling haloes. The computation of BH spins is done taking into account recent works on the subject (Shakura & Sunyaev 1973; King et al. 2005; Lodato & Pringle 2006; Volonteri, Sikora & Lasota2007). In this model, BH spins are determined exclusively by the accretion history; magneto-hydrodynamics and general relativity effects are not taken into account. Here we show how the accretion from a warped disc influences the evolution of BH spins with a detailed study on the contribution from each accretion mechanism. We find that our model follows the "spin paradigm".