Feedback from central black holes in elliptical galaxies. III: models with both radiative and mechanical feedback - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




Feedback from central black holes in elliptical galaxies. III: models with both radiative and mechanical feedback - Astrophysics > Cosmology and Nongalactic Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We find, from high-resolution hydro simulations, that winds from AGNeffectively heat the inner parts ~100 pc of elliptical galaxies, reducinginfall to the central SMBH; and radiative photoionization and X-ray heatingreduces cooling flows at the kpc scale. Including both types of feedback withpeak efficiencies of 3 10^{-4} < epsilon mech < 10^{-3} and of epsilon rad~10^{-1.3} respectively, produces systems having duty-cycles, central SMBHmasses, X-ray luminosities, optical light profiles, and E+A spectra in accordwith the broad suite of modern observations of massive elliptical systems. Ourmain conclusion is that mechanical feedback including all three of energy,momentum and mass is necessary but the efficiency, based on severalindependent arguments must be a factor of 10 lower than is commonly assumed.Bursts are frequent at z>1 and decline in frequency towards the present epochas energy and metal rich gas are expelled from the galaxies into thesurrounding medium. For a representative galaxy of final stellar mass ~310^{11} Msun, roughly 3 10^{10} Msun of recycled gas has been added to the ISMsince z~2 and, of that, roughly 63% has been expelled from the galaxy, 19% hasbeen converted into new metal rich stars in the central few hundred parsecs,and 2% has been added to the central SMBH, with the remaining 16% in the formhot X-ray emitting ISM. The bursts occupy a total time of ~170 Myr, which isroughly 1.4% of the available time. Of this time, the central SMBH would beseen as an UV or optical source for ~45% and ~71$% of the time, respectively.Restricting to the last 8.5 Gyr, the burst occupy ~44 Myr, corresponding to afiducial duty-cycle of ~5 10^{-3}.



Autor: L. Ciotti Dept. of Astronomy, Univ. of Bologna, J.P. Ostriker Princeton University and IoA Cambridge, D. Proga Dept. of Physics a

Fuente: https://arxiv.org/







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