Institute for Astronomy, University of Edinburgh
Recent years advances in NIR detectors have provided us with a treasure trove of deep multiband observations (e.g. CANDELS) that place the peak of star formation at z=2 from UV to IR and trace the buildup of stellar mass up to ever increasing redshifts. In particular, the existence of a subpopulation of emission-line galaxies facilitates the study of star formation and gas properties at high-z, because the nebular component outshinines the continuum. Instead of using traditional spectra or narrowband photometry, we adapt the usual broadband colour-colour selection methods to scan for colour excesses due to nebular emission down to lower-mass galaxies.
In this way we can simultaneously measure equivalent widths of Ha, OIII and OII from z=0.3 to z=5 using a variety of filter combinations from U to IRAC 4.5. So far we have found that the fraction of ELGs can reach up to 40% (EW>150A) at the peak of SF with EW distributions building up long tails reaching 1000A towards z=2, with some evidence of increasing OIII/OII ratios. Finally, Mass-redshift-EW distributions for all three emission lines are built and compared with complementary spectroscopic (3DHST) and narrowband (HiZELS) results.
2015 July 22, 15:00
Observatório Astronómico de Lisboa (Seminar room)
Tapada da Ajuda, 1349-018 Lisboa