Examinando por Autor "Coelho P."

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    Assessing the photometric redshift precision of the S-PLUS survey: The Stripe-82 as a test-case
    (Oxford University Press, 2020-12) Molino A.; Costa-Duarte M.V.; Sampedro L.; Herpich F.R.; Sodré L.; Jr. Mendes de Oliveira C.; 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.; Lopes de Oliveira R.; Torres-Flores S.; Lima-Dias C.; Nilo Castellon J.L.; 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.; Thom de Souza R.C.; 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.
    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 seven 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 deg2 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 ∼100 k galaxies, we find a precision of σz <0.8 per cent, <2.0 per cent, or <3.0 per cent for galaxies with magnitudes r < 17, <19, and <21, respectively. A precision of 0.6 per cent is attained for galaxies with the highest Odds values. These estimates have a negligible bias and a fraction of catastrophic outliers inferior to 1 per cent. We identify a redshift window (i.e. 0.26 < z < 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 ∼2 M, ∼16 M and ∼32 M galaxies in the S-PLUS survey with a photo-z precision of σz <1.0 per cent, <2.0 per cent, and <2.5 per cent after observing 8000 deg2. We also derive redshift probability density functions, proving their reliability encoding redshift uncertainties and their potential recovering the n(z) of galaxies at z < 0.4, with an unprecedented precision for a photometric survey in the Southern hemisphere. © 2020 The Author(s)
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    One Hundred SMUDGes in S-PLUS: Ultra-diffuse Galaxies Flourish in the Field
    (Institute of Physics Publishing, 2020-04) Barbosa C.E.; Zaritsky D.; Donnerstein R.; Zhang H.; Dey A.; De Oliveira, C. Mendes; Sampedro L.; Molino A.; Costa-Duarte M.V.; Coelho P.; Cortesi A.; Herpich F.R.; Hernandez-Jimenez J.A.; Santos-Silva T.; Pereira E.; Werle A.; Overzier R.A.; Cid Fernandes R.; Castelli, A. V. Smith; Ribeiro T.; Schoenell W.; Kanaan A.
    We present the first systematic study of the stellar populations of ultra-diffuse galaxies (UDGs) in the field, integrating the large area search and characterization of UDGs by the SMUDGes survey with the twelve-band optical photometry of the S-PLUS survey. Based on Bayesian modeling of the optical colors of UDGs, we determine the ages, metallicities, and stellar masses of 100 UDGs distributed in an area of ∼330 deg2 in the Stripe 82 region. We find that the stellar masses and metallicities of field UDGs are similar to those observed in clusters and follow the trends previously defined in studies of dwarf and giant galaxies. However, field UDGs have younger luminosity-weighted ages than do UDGs in clusters. We interpret this result to mean that field UDGs have more extended star formation histories, including some that continue to form stars at low levels to the present time. Finally, we examine stellar population scaling relations that show that UDGs are, as a population, similar to other low surface brightness galaxies.