GALAXY STRUCTURE AND MODE OF STAR FORMATION IN THE SFR-MASS PLANE FROMz∼ 2.5 TOz∼ 0.1

Abstract

We analyze the dependence of galaxy structure (size and Sersic index) and mode of star formation (Σ SF R and SF R IR /SF R UV ) on the position of galaxies in the SFR versus Mass diagram. Our sample comprises roughly 640000 galaxies at z ∼ 0.1, 130000 galaxies at z ∼ 1, and 36000 galaxies at z ∼ 2. Structural measurements for all but the z ∼ 0.1 galaxies are based on HST imaging, and SFRs are derived using a Herschel-calibrated ladder of SFR indicators. We find that a correlation between the structure and stellar population of galaxies (i.e., a 'Hubble sequence') is already in place since at least z ∼ 2.5. At all epochs, typical star-forming galaxies on the main sequence are well approximated by exponential disks, while the profiles of quiescent galaxies are better described by de Vaucouleurs profiles. In the upper envelope of the main sequence, the relation between the SFR and Sersic index reverses, suggesting a rapid build-up of the central mass concentration in these starbursting outliers. We observe quiescent, moderately and highly star-forming systems to co-exist over an order of magnitude or more in stellar mass. At each mass and redshift, galaxies on the main sequence have the largest size. The rate of size growth correlates with specific SFR, and so does Σ SF R at each redshift. A simple model using an empirically determined SF law and metallicity scaling, in combination with an assumed geometry for dust and stars is able to relate the observed Σ SF R and SF R IR /SF R UV , provided a more patchy dust geometry is assumed for high-redshift galaxies.

The impact of galactic properties and environment on the quenching of central and satellite galaxies: a comparison between SDSS, Illustris and L-Galaxies

“…This is true both intrinsically and at a fixed stellar mass. However, in this work we have found that stellar mass is not the most fundamental parameter which governs the quenching of central galaxies (consistent with several other studies, e.g., Wuyts et al 2011;Wake et al 2012;Cheung et al 2012;Fang et al 2013;Bluck et al 2014;Woo et al 2015;Teimoorinia et al 2016). This is important because the aim behind binning at a fixed stellar mass is to effectively control for the intrinsic drivers to quenching (the sole drivers for central galaxies) before investigating what additional (most probably environmental) processes quench satellite galaxies.…”

“…bulge-to-total light/ mass ratio, B/T , or Sérsic index, nS (e.g., Driver et al 2006;Wuyts et al 2011;Mendel et al 2013;Bluck et al 2014;Lang et al 2014;Omand et al 2014). Additionally, the quenched fraction depends on environment, particularly the surface density of galaxies in a given region of space, the halo mass of the group or cluster, and the distance a galaxy resides at from the centre of its group (e.g., Balogh et al 2004;van den Bosch et al 2007Peng et al 2012;Woo et al 2013;Bluck et al 2014).…”

Star formation properties of sub-mJy radio sources

“…; Daddi et al 2007;Elbaz et al 2007;Pannella et al 2009;Peng et al 2010;Rodighiero et al 2011;Wuyts et al 2011).…”

Galaxy Growth at Early Times from 3D Studies

“…The balance between accretion and star formation maintains galaxies on a tight "main sequence" (MS) in stellar mass (M ) vs star formation rate (SFR), with ∼ 0.3 dex scatter, whose evolution reflects the decrease in cosmic SFR density from its peak around z ∼ 2 to the winding down epochs at z 1 (e.g., Elbaz et al 2007;Rodighiero et al 2011;Whitaker et al 2012). This scenario is further empirically motivated by the evolution of molecular gas mass fractions and the dominance of disk-like systems among MS star-forming galaxies (SFGs) out to z ∼ 2.5 (e.g., Förster Schreiber et al 2009;Wuyts et al 2011;Tacconi et al 2013;Wisnioski et al 2014). The growth of galaxies thus appears to be tightly regulated, until they reach M ∼ 10 11 M where their star formation is rapidly quenched (e.g., Peng et al 2010).…”

“…Concurring evidence for the prevalence of high-z disks has come from HST-based studies of rest-UV/optical morphologies and stellar mass distributions of large mass-selected samples out to z ∼ 2.5, which showed that MS SFGs typically have a disk-like stellar structure with a systematic increase of bulge-to-disk ratio towards high masses (e.g. Wuyts et al 2011;Lang et al 2014). These results from kinematics and stellar structure provided some of the compelling evidence that smoother mass accretion modes onto galaxies and internal dynamical processes within galaxies play an important -if not dominant -role in growing galaxies.…”