Emission Line Galaxy Demographics in the last 10 Gyrs with CANDELS Broadband Colours
Dust, Gas and Star Formation in Galaxies Throughout Cosmic Time
Joao Pedro Ferreira
University of Edinburgh
James Dunlop, Vivienne Wild
Concerted efforts in high-z galaxy evolution in recent years have formed a consistent picture of rising star formation, peaking at z=2 that exponentially decreases until today. Yet, the details of how this transition from a gas-rich, bursty universe to today's largely quiescent one needs an explanation, especially in the light of the evidence for a main sequence of star formation and different feedback properties of galaxies below and above the knee of the mass function.

A better understanding of galaxy formation needs large samples of objects down to the masses of dwarf galaxies:

Using a combination of the wealth of deep (H200A) emission-line galaxies (ELGs) in [OII], [OIII] and H-alpha and estimate equivalent widths (EWs) to produce ELG EW distributions over 0.310^9 for all these lines.

The results agree with theoretical models and complementary observations like narrowband or spectroscopic measurements.
The EW distributions display long tails of extreme equivalent widths for [OIII] and H-alpha and, more surprisingly, very high fractions (up to 30%) of ELGs in the described mass range.
While [OIII] and H-alpha fractions both increase from z=0.3 to z=2, [OII] does not follow this increase, which indicates that a transition in [OIII]/[OII] and ionization parameter is at work at z=2 for these objects.
16:30 - 18:00