halo mass, and therefore the correlation between median halo mass and local density is an important cause of the SFR-density relation at both redshifts. We also show that the local density on 1 $h^{-1}$ Mpc scales affects galaxy SFRs as much as halo mass at $z$=0. Finally, we find indications that the role of the 1 $h^{-1}$ Mpc scale environment reverses from $z$=0 to $z$=1: at $z$=0 high-density environments depress galaxy SFRs, while at $z$=1 high-density environments tend to increase SFRs.'
author:
- Stephanie Tonnesen$^1$ and Renyue Cen$^2$
title: 'On the Reversal of SFR-density Relation at z=1: Insights from Simulations'
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Introduction
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In the nearby universe, the morphology, color, star formation rate (SFR), and mass of galaxies is correlated with local environmental density. Specifically, galaxies tend to be earlier types, more massive, redder and to have lower SFRs and specific SFRs (sSFR $\equiv$ SFR/M$_*$) in higher density environments (Dressler 1980; Oemler 1974; Balogh et al. 2001; Blanton et al. 2003; Hogg et al. 2004; Balogh et al. 1998; Hashimoto et al. 1998; G[ó]{}mez et al. 2003). While galaxy morphology, color, and SFR also depend on mass (e.g. de Vaucouleurs 1960; de Vaucouleurs 1962; Strateva et al. 2001; Blanton et 