Abstract
We propose the Cosmic Web Detachment (CWD) model, a framework to interpret the star-formation history of galaxies in a cosmological context. The CWD model unifies several starvation mechanisms known to disrupt or stop star formation into one single physical framework. Galaxies begin accreting star-forming gas at early times via a network of primordial filaments, simply related to the pattern of density fluctuations in the initial conditions. But when streams cross on intergalactic scales, this pattern is disrupted, and the galaxy <em>detaches</em> from its primordial filaments, ending the accretion of cold gas. We argue that CWD encompasses known external processes halting star formation, such as harassment, strangulation and starvation. On top of these external processes, internal feedback processes such as AGN contribute to stop in star formation as well. We introduce a simple formalism to identify CWD events and quenched galaxies in dark-matter <em>N</em>-body simulations. With it we reproduce and explain, in the context of CWD, several observations including downsizing, the cosmic star formation rate history, the galaxy mass-color diagram and the dependence of the fraction of red galaxies with mass and local density.
Highlights
Star formation quenching, its underlying mechanism and what triggers it, is one of the most pressing problems in modern galaxy formation
When shell-crossing occurs on intergalactic scales, this pattern is disrupted, and the galaxy detaches from its primordial filaments, ending the accretion of cold gas
We argue that Cosmic Web Detachment (CWD) encompasses known external processes halting star formation, such as harassment, strangulation and starvation
Summary
Star formation quenching, its underlying mechanism and what triggers it, is one of the most pressing problems in modern galaxy formation. The spatial correlation of galaxy properties, up to scales of several megaparsecs, points to the dominant role of environment on galaxy evolution (Dressler 1980; Weinmann et al 2006; Kauffmann et al 2013). Both observations and simulations point to star formation quenching being the result of both environmental (external) processes and feedback (internal) processes (Hogg et al 2003; Blanton et al 2005; Peng et al 2010; van de Voort et al 2011) but their relative importance is not clear yet. Halo mass and density are correlated, making this relation not straightforward to interpret
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