2018/11/29 by Pierandrea Guarnieri, P. Guarnieri, Claudia Maraston +92 · 19 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Photometric redshift #Physics #Population #Redshift #Spectral energy distribution #Star formation #Stars #Stellar mass #Stellar population #astro-ph.GA
paper · pdf · doi:10.1093/mnras/sty3305
published in Monthly Notices of the Royal Astronomical Society 483(3), 3060-3081 (Oxford University Press) · 24 pages (41 with appendix), 16 figures, MNRAS in press
arxiv created 2018/11/29 · openalex publication_date 2018/12/03 · openalex created_date 2018/12/11 · arxiv updated 2018/12/12 · openalex updated_date 2026/08/06
Using stellar population models, we predicted that the Dark Energy Survey (DES) -due to its special combination of area (5000 deg 2 ) and depth (i = 24.3) -would be in the position to detect massive ( 10 11 M ) galaxies at z 4. We confront those theoretical calculations with the first 150 deg 2 of DES data reaching nominal depth. From a catalogue containing 5 million sources, 26 000 were found to have observed-frame gr versus ri colours within the locus predicted for z 4 massive galaxies. We further removed contamination by stars and artefacts, obtaining 606 galaxies lining up by the model selection box. We obtained their photometric redshifts and physical properties by fitting model templates spanning a wide range of star formation histories, reddening and redshift. Key to constrain the models is the addition, to the optical DES bands g, r, i, z, and Y, of near-IR J, H, K s data from the Vista Hemisphere Survey. We further applied several quality cuts to the fitting results, including goodness of fit and a unimodal redshift probability distribution. We finally select 233 candidates whose photometric redshift probability distribution function peaks around z 4, have high stellar masses [log (M * /M ) 11.7 for a Salpeter IMF] and ages around 0.1 Gyr, i.e. formation redshift around 5. These properties match those of the progenitors of the most massive galaxies in the local Universe. This is an ideal sample for spectroscopic followup to select the fraction of galaxies which are truly at high redshift. These initial results and those at the survey completion, which we shall push to higher redshifts, will set unprecedented constraints on galaxy formation, evolution, and the re-ionization epoch.