S315.11.04 — Main-sequence of star-formation, between universality and tension

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Aug 6th at 2:55 PM until 3:20 PM

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Author(s): David Elbaz1

Institution(s): 1. CEA Saclay

We will present a new method to push the deepest Herschel surveys even deeper in sensitivity and redshift range. A comparison to UV techniques such as the Lyman break technique will be given showing that a population of M*>5x10^10 Msun galaxies is systematically missed by this standard approach at high z. We will discuss how SFR estimates of starbursting galaxies can be wrongly estimated when using the UV corrected for extinction. A discussion of the relative growth of disks and bulges will be presented.
We will show that at least 2/3 of the star-formation history of galaxies took place in a main-sequence mode, i.e. with a characteristic specific SFR +/- 0.3 dex, suggesting that star-formation at the scale of galaxies over the Hubble time is a relatively universal process. This result matches surprisingly well the cold flow paradigm which states that at least 2/3 of the mass growth of galaxies came from smooth accretion of intergalactic matter suggesting that the main-sequence is a direct result of smooth gas accretion. However we will also show that both paradigms lead to a major tension in their relative growth rates as a function of cosmic time showing that either a major regulatory process of star-formation is still missing or that we misunderstand the behavior of baryons at large scales.