The morgana model for the rise of galaxies and active nuclei

Abstract

We present the Model for the Rise of Galaxies and Active Nuclei (MORGANA), a new code for the formation and evolution of galaxies and active galactic nuclei (AGNs). Starting from the merger trees of dark matter (DM) haloes and a model for the evolution of substructure within the haloes, the complex physics of baryons is modelled with a set of state-of-the-art models that describe the mass, metal and energy flows between the various components (baryonic halo, bulge, disc) and phases (cold and hot gas, stars) of a galaxy. These flows are then numerically integrated to produce predictions for the evolution of galaxies. The processes of shock-heating and cooling, star formation, feedback, galactic winds and superwinds, accretion on to black holes and AGN feedback are described by new models. In particular, the evolution of the halo gas explicitly follows the thermal and kinetic energies of the hot and cold phases, while star formation and feedback follow the results of the multiphase model recently proposed by Monaco. The increased level of sophistication of these models allows to move from a phenomenological description of gas physics, based on simple scalings with the depth of the DM halo potential, towards a fully physically motivated one. We deem that this is fully justified by the level of maturity and rough convergence reached by the latest versions of numerical and semi-analytic models of galaxy formation. The comparison of the predictions of MORGANA with a basic set of galactic data reveals from the one hand an overall rough agreement, and from the other hand highlights a number of well-or less-known problems: (i) producing the cut-off of the luminosity function requires to force the quenching of the late cooling flows by AGN feedback, (ii) the normalization of the Tully-Fisher relation of local spirals cannot be recovered unless the DM haloes are assumed to have a very low concentration, (iii) the mass function of H I gas is not easily fitted at small masses, unless a similarly low concentration is assumed, (iv) there is an excess of small elliptical galaxies at z = 0. These discrepancies, more than the points of agreement with data, give important clues on the missing ingredients of galaxy formation.

Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation

“…A central, "seed" black hole is expected to gradually grow via gas accretion, eventually becoming massive enough to shine as a quasar and trigger powerful winds and/or jets that are capable of removing gas and quenching or inhibiting star formation in the host galaxy ("quasar-mode" and "radio-mode" feedbacks). Feedback from an active black hole has indeed become a key ingredient in many galaxy evolution models (e.g., Granato et al 2004;Bower et al 2006;Croton et al 2006;Monaco et al 2007;Sijacki et al 2015). At later times, both the host galaxy and its black hole may further increase their mass (and size) via a sequence of mergers with other galaxies/black holes.…”

On the dependence of galaxy morphologies on galaxy mergers

“…In this work we consider predictions from three different stateof-the-art SAMs, namely MORGANA (Monaco et al 2007), the De Lucia & Blaizot (2007, DLB07 hereafter) version of the Munich model and the Santa Cruz model (SC-SAM , Somerville et al 2008;Porter et al 2014). In particular, we consider the MORGANA run defined in Lo Faro et al (2009) and calibrated on WMAP3 cosmology (H0 = 72 km s −1 Mpc −1 , Ωm = 0.24, σ8 = 0.8, n = 0.96, ΩΛ = 0.76); the DLB07 model applied to the Millen- Figure 1.…”

The new semi-analytic code GalICS 2.0 – reproducing the galaxy stellar mass function and the Tully–Fisher relation simultaneously

“…An early version had already been presented in a comparison of all the main SAMs (Knebe et al 2015). The models that participated to this comparison are those by Bower et al (2006), Font et al (2008), Gonzalez-Perez et al (2014), Croton et al (2006), De Lucia & Blaizot (2007), Henriques et al (2013), Benson (2012), Monaco et al (2007) , Gargiulo et al (2015), Somerville et al (2008) and Lee & Yi (2013).…”