Assessing the photometric redshift precision of the S-PLUS survey: the Stripe-82 as a test-case.

Publication date: 
Main author: 
Molino, A.
IAA authors: 
Benítez, N.
Molino, A.;Costa-Duarte, M. V.;Sampedro, L.;Herpich, F. R.;Sodré, L., Jr.;de Oliveira, C. Mendes;Schoenell, W.;Barbosa, C. E.;Queiroz, C.;Lima, E. V. R.;Azanha, L.;Muñoz-Elgueta, N.;Ribeiro, T.;Kanaan, A.;Hernandez-Jimenez, J. A.;Cortesi, A.;Akras, S.;de Oliveira, R. Lopes;Torres-Flores, S.;Lima-Dias, C.;Castellon, J. L. Nilo;Damke, G.;Alvarez-Candal, A.;Jiménez-Teja, Y.;Coelho, P.;Pereira, E.;Montero-Dorta, A. D.;Benítez, N.;Gonçalves, T. S.;Santana-Silva, L.;Werner, S. V.;Almeida, L. A.;Lopes, P. A. A.;Chies-Santos, A. L.;Telles, E.;de Souza, Thom;C, R.;Gonçalves, D. R.;de Souza, R. S.;Makler, M.;Buzzo, M. L.;Placco, V. M.;Nakazono, L. M. I.;Saito, R. K.;Overzier, R. A.;Abramo, L. R.
Monthly Notices of the Royal Astronomical Society
Publication type: 
In this paper we present a thorough discussion about the photometric redshift (photo-z) performance of the Southern Photometric Local Universe Survey (S-PLUS). This survey combines a 7 narrow + 5 broad passband filter system, with a typical photometric-depth of r∼21 AB. For this exercise, we utilize the Data Release 1 (DR1), corresponding to 336 deg<SUP>2</SUP> from the Stripe-82 region. We rely on the BPZ2 code to compute our estimates, using a new library of SED models, which includes additional templates for quiescent galaxies. When compared to a spectroscopic redshift control sample of ∼100k galaxies, we find a precision of σ<SUB>z</SUB> &lt;0.8%, &lt;2.0% or &lt;3.0% for galaxies with magnitudes r&lt;17, &lt;19 and &lt;21, respectively. A precision of 0.6% is attained for galaxies with the highest Odds values. These estimates have a negligible bias and a fraction of catastrophic outliers inferior to 1%. We identify a redshift window (i.e., 0.26&lt;z &lt;0.32) where our estimates double their precision, due to the simultaneous detection of two emission-lines in two distinct narrow-bands; representing a window opportunity to conduct statistical studies such as luminosity functions. We forecast a total of ∼2M, ∼16M and ∼32M galaxies in the S-PLUS survey with a photo-z precision of σ<SUB>z</SUB> &lt;1.0%, &lt;2.0% and &lt;2.5% after observing 8000 deg<SUP>2</SUP>. We also derive redshift Probability Density Functions, proving their reliability encoding redshift uncertainties and their potential recovering the n(z) of galaxies at z &lt; 0.4, with an unprecedented precision for a photometric survey in the southern hemisphere.
ADS Bibcode: 
cosmology: large-scale structure of Universe;galaxies: distances and redshifts;galaxies: photometry;galaxies: clusters: general;surveys;Astrophysics - Astrophysics of Galaxies