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Canis Major OB1 (CMa OB1) is a Galactic stellar association with a very intriguing star-formation scenario. There are more than two dozen known star clusters in its line of sight, but it is not clear which ones are physically associated with CMa OB1. We use a clustering code that employs 5-dimensional data from the Gaia DR2 catalogue to identify physical groups and obtain their astrometric parameters and, in addition, we use two different isochrone-fitting methods to estimate the ages of these groups. We find 15 stellar groups with distances between 570 pc and 1650 pc, including 10 previously known and 5 new open cluster candidates. Four groups, precisely the youngest ones ($, Comment: 23 pages, 28 figures, 7 tables

Authors: 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.; 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., 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, AM would like to acknowledge the financial support of the Brazilian funding agency FAPESP (Post-doc fellowship - process number 2014/11806-9), and his colleague Dr. Carlos Lopez-Sanjuan for all his valuable advices regarding PDF analysis. Likewise, AM acknowledges Ulisses Manzo and Carlos E. Paladini at IAG/USP for helping with software installation. In addition, AM would like to dedicate this work to his first son Tiago who was born in Brazil during the time this paper was written. MVCD thanks his scholarship from FAPESP (processes 2014/18632-6 and 2016/052549). This work has used the computing facilities of the Laboratory of Astroinformatics (IAG/USP, NAT/Unicsul), whose purchase was made possible by the Brazilian agency FAPESP (grant 2009/540064) and the INCT-A. LS acknowledges the financial support of the Brazilian funding agency FAPESP (Post-doc fellowship -process number 2016/21664-2). The S-PLUS project, including the T80S robotic telescope and the S-PLUS scientific survey, was founded as a partnership between the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), the Observatorio Nacional (ON), the Universidade Federal de Sergipe (UFS), and the Universidade Federal de Santa Catarina (UFSC), with important financial and practical contributions from other collaborating institutes in Brazil, Chile (Universidad de La Serena), and Spain (Centro de Estudios de Fisica del Cosmos de Aragon, CEFCA). LSJ acknowledges support from FAPESP and CNPq. CMdO acknowledges support from FAPESP (grants 2009/54202-8, 2011/51680-6, 2014/07684-5, 2016/17119-9, 2017/50277-0, and 2019/11910-4) and CNPq (grant 312333/20145). JLNC is grateful for financial support received from the grant programs FA9550-15-1-0167 and FA9550-18-1-0018 of the Southern Office of Aerospace Research and Development (SOARD), a branch of theAir ForceOffice of the ScientificResearch International Office of the United States (AFOSR/IO). ADMD thanks FAPESP for financial support. SA acknowledges financial support from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq, grant 454794/2015-0). AAC acknowledges support from FAPERJ (grant E26/203.186/2016) and CNPq (grants 304971/20162 and 401669/2016-5). LAA would like to acknowledge the financial support from FAPESP (N 2012/09716-6, 2013/18245-0). AC acknowledges funding from CNPq (403580/2016-1, 311153/20186) and FAPERGS (17/2551-0001). JAHJ thanks Brazilian institution CNPq for financial support through postdoctoral fellowship (project 150237/2017-0) and Chilean institution CONICYT, Programa de Astronomia, Fondo ALMA-CONICYT 2017, Codigo de proyecto 31170038. PAAL thanks the support of CNPq, grant 309398/20185. We are grateful for the contributions of CTIO staff in helping in the construction, comissioning, andmaintenance of the telescope and camera, and we are particularly thankful to the CTIO director, Steve Heathcote, for his support at every phase, without which this project would not have been completed. We thank Cesar Iniguez for making the 2D measurements of the filter transmissions at CEFCA. We warmly thank David Cristobal-Hornillos and his group for helping us to install and run the reduction package JYPE version 0.9.9 in the SPLUS computer system in Chile. We warmly thank Mariano Moles, Javier Cenarro, Tamara Civera, Sergio Chueca, Javier Hernandez Fuertes, AntonioMarin Franch, JesusVareta, Hector-VazquezRamio, and Alessandro Ederoclite - the success of the S-PLUS project relies on the dedication of these and other CEFCA staff members in building OAJ and running J-PLUS and J-PAS. We deeply thank Rene Laporte and INPE, as well as Keith Taylor, for their contributions to the T80S camera.

This work presents the medium-resolution ($R \sim 1,500$) spectroscopic follow-up of 522 low-metallicity star candidates from the Southern Photometric Local Universe Survey (S-PLUS). The objects were selected from narrow-band photometry, taking advantage of the metallicity-sensitive S-PLUS colors. The follow-up observations were conducted with the Blanco and Gemini South telescopes, using the COSMOS and GMOS spectrographs, respectively. The stellar atmospheric parameters (T$_{\rm eff}$, log$g$, and [Fe/H]), as well as carbon and $\alpha$-element abundances, were calculated for the program stars in order to assess the efficacy of the color selection. Results show that $92^{+2}_{-3}\%$ of the observed stars have [Fe/H]$\leq -1.0$, $83^{+3}_{-3}\%$ have [Fe/H]$\leq -2.0$, and $15^{+3}_{-3}\%$ have [Fe/H]$\leq -3.0$, including two ultra metal-poor stars ([Fe/H]$\leq -4.0$). The 80th percentile for the metallicity cumulative distribution function of the observed sample is [Fe/H]$= -2.04$. The sample also includes 68 Carbon-Enhanced Metal-Poor (CEMP) stars. Based on the calculated metallicities, further S-PLUS, color cuts are proposed, which can increase the fractions of stars with [Fe/H]$\leq -1.0$ and $\leq -2.0$ to $98\%$ and $88\%$, respectively. Such high success rates enable targeted high-resolution spectroscopic follow-up efforts, as well as provide selection criteria for fiber-fed multiplex spectroscopic surveys., Comment: 21 pages, 10 figures, accepted for publication on ApJS

The presence of Multiple Stellar Populations (MSPs) in Galactic Globular Clusters (GCs) is a poorly understood phenomenon. By probing different spectral ranges that are affected by different absorption lines using the multi-band photometric survey S-PLUS, we study four GCs -- NGC 104, NGC 288, NGC 3201 and NGC 7089 -- that span a wide range in metallicities. With the combination of broad and narrow-band photometry in 12 different filters from 3485A (u) to 9114A (z), we identified MSPs along the rectified red-giant branch in colour-magnitude diagrams (CMDs) and separated them using a K-means clustering algorithm. Additionally, we take advantage of the large Field of View of the S-PLUS detector to investigate radial trends in our sample. We report on six colour combinations that can be used to successfully identify two stellar populations in all studied clusters and show that they can be characterized as Na-rich and Na-poor. For both NGC 288 and NGC 7089, their radial profiles show a clear concentration of 2P. This directly supports the formation theories that propose an enrichment of the intra-cluster medium and subsequent star formation in the more dense central regions. However, in the case of NGC 3201, the trend is reversed. The 1P is more centrally concentrated, in direct contradiction with previous literature studies. NGC 104 shows a well-mixed population. We also constructed radial profiles up to 1 half-light radius of the clusters with HST data to highlight that radial differences are lost in the inner regions of the GCs and that wide-field studies are essential when studying this., Comment: 9 pages, 11 figures

In this paper, we describe a new method to select globular cluster (GC) candidates, including galaxy subtraction with unsharp masking, template fitting techniques, and the inclusion of Gaia’s proper motions. We report the use of the 12-band photometric system used by S-PLUS to determine radial velocities and stellar populations of GCs around nearby galaxies. Specifically, we assess the effectiveness of identifying GCs around nearby and massive galaxies (D < 20 Mpc and σ > 200 km s-1) in a multiband survey such as S-PLUS by using spectroscopically confirmed GCs and literature GC candidate lists around the bright central galaxy in the Fornax cluster, NGC 1399 (D = 19 Mpc), and the isolated lenticular galaxy NGC 3115 (D = 9.4 Mpc). Despite the shallow survey depth, which limits this work to r < 21.3 mag, we measure reliable photometry and perform robust SED fitting for a sample of 115 GCs around NGC 1399 and 42 GCs around NGC 3115, recovering radial velocities, ages, and metallicities for the GC populations. © 2021 The Author(s)., MLB and CMdO acknowledge the financial support of the Sao Paulo Research Foundation (FAPESP) under grant 2019/23388-0. CEB acknowledges FAPESP, grant2016/12331-0. PC acknowledges support from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) under grant 310041/2018-0. DdBS also acknowledges Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) process number 2017/00204-6 for the financial support. AC-S acknowledge funding from the brazilian agencies Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and the Fundação de Amparo à Pesquisa do Estado do RS (FAPERGS) through grants CNPq-403580/2016-1, CNPq-11153/2018-6, PqG/FAPERGS-17/2551-0001, FAPERGS/CAPES 19/2551-0000696-9, L’Oréal UNESCO ABC Para Mulheres na Ciência and the Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (PIFI) through grant E085201009. AA-C acknowledges support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This work was funded with grants from Consejo Nacional de Investigaciones Científicas y Técnicas and Universidad Nacional de La Plata (Argentina). The S-PLUS project, including the T80-South robotic telescope and the S-PLUS scientific survey, was founded as a partnership between the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), the Observatório Nacional (ON), the Federal University of Sergipe (UFS), and the Federal University of Santa Catarina (UFSC), with important financial and practical contributions from other collaborating institutes in Brazil, Chile (Universidad de La Serena), and Spain (Centro de Estudios de Física del Cosmos de Aragón, CEFCA). We further acknowledge financial support from the São Paulo Research Foundation (FAPESP), the Brazilian National Research Council (CNPq), the Coordination for the Improvement of Higher Education Personnel (CAPES), the Carlos Chagas Filho Rio de Janeiro State Research Foundation (FAPERJ), and the Brazilian Innovation Agency (FINEP). The authors are grateful for the contributions from CTIO staff in helping in the construction, commissioning, and maintenance of the T80-South telescope and camera. We are also indebted to Rene Laporte and INPE, as well as Keith Taylor, for their important contributions to the project. We also thank CEFCA staff for their help with T80-South, specifically we thank Antonio Marín-Franch for his invaluable contributions in the early phases of the project, David Cristóbal-Hornillos and his team for their help with the installation of the data reduction package jype version 0.9.9, César Íãiguez for providing 2D measurements of the filter transmissions, and all other staff members for their support.

Ultra-diffuse galaxies (UDGs) are extremely low luminosity galaxies and some of them seem to have a lack of dark matter. Therefore, they can offer important clues to better understand galaxy formation and evolution. Little is known about UDGs in less dense environments, as most of the known UDGs have been found in very dense regions, in the outskirts of massive galaxies in galaxy clusters. In this work, we present the properties of UDGs candidates identified through visual inspection around the low-density environment of NGC 3115, the closest S0 galaxy from the Milky Way. We have measured the structural parameters of 41 UDGs candidates using images obtained with the Dark Energy Camera at the Blanco Telescope. Such structural parameters will be used to characterise and select the best UDG candidates, that will have their properties traced for future follow-up campaigns.

We present the results of the optical follow-up, conducted by the TOROS collaboration, of gravitational wave events detected during the Advanced LIGO-Virgo second observing run (Nov 2016 -- Aug 2017). Given the limited field of view ($\sim100\arcmin$) of our observational instrumentation we targeted galaxies within the area of high localization probability that were observable from our sites. We analyzed the observations using difference imaging, followed by a Random Forest algorithm to discriminate between real and bogus transients. For all three events that we respond to, except GW170817, we did not find any bona fide optical transient that was plausibly linked with the observed gravitational wave event. Our observations were conducted using telescopes at Estaci\'{o}n Astrof\'{\i}sica de Bosque Alegre, Cerro Tololo Inter-American Observatory, and the Dr. Cristina V. Torres Memorial Astronomical Observatory. Our results are consistent with the LIGO-Virgo detections of a binary black hole merger (GW170104) for which no electromagnetic counterparts were expected, as well as a binary neutron star merger (GW170817) for which an optical transient was found as expected., Comment: 9 pages, 4 figures

In this study we define a new sample of distant powerful radio galaxies in order to study their host-galaxy properties and provide targets for future observations of HI absorption with new radio telescopes and to understand the fuelling and feedback from such sources. We have cross-matched the Sydney University Molonglo Sky Survey (SUMSS) radio catalogue at 843 MHz with the VISTA Hemisphere Survey (VHS) near-infrared catalogue using the Likelihood Ratio technique. Photometric redshifts from the Dark Energy Survey are then used to assign redshifts to the radio source counterparts. We found a total of 249 radio sources with photometric redshifts over a 148 deg^2 region. By fitting the optical and near-infrared photometry with spectral synthesis models we determine the stellar mass and star-formation rates of the radio sources, finding typical stellar masses of 10^{11} - 10^{12}M$_{\odot}$ for the powerful high-redshift radio galaxies. We also find a population of low-mass blue galaxies. However, by comparing the derived star-formation rates to the radio luminosity, we suggest that these sources are false positives in our likelihood ratio analysis. Follow up, higher-resolution (, 11 pages, 9 figures. Accepted for publication in MNRAS

We report photometric estimates of effective temperature, $T_{\rm eff}$, metallicity, [Fe/H], carbonicity, [C/Fe], and absolute carbon abundances, $A{\rm (C)}$, for over 700,000 stars from the Southern Photometric Local Universe Survey (S-PLUS) Data Release 2, covering a substantial fraction of the equatorial Sloan Digital Sky Survey Stripe 82. We present an analysis for two stellar populations: 1) halo main-sequence turnoff stars and 2) K-dwarf stars of mass $0.58 < M/M_{\odot}, 27 pages, 14 figures, 3 tables, Accepted for publication in ApJ

This paper provides a catalogue of stars, quasars, and galaxies for the Southern Photometric Local Universe Survey Data Release 2 (S-PLUS DR2) in the Stripe 82 region. We show that a 12-band filter system (5 Sloan-like and 7 narrow bands) allows better performance for object classification than the usual analysis based solely on broad bands (regardless of infrared information). Moreover, we show that our classification is robust against missing values. Using spectroscopically confirmed sources retrieved from the Sloan Digital Sky Survey DR16 and DR14Q, we train a random forest classifier with the 12 S-PLUS magnitudes + 4 morphological features. A second random forest classifier is trained with the addition of the W1 (3.4 μm) and W2 (4.6 μm) magnitudes from the Wide-field Infrared Survey Explorer (WISE). Forty-four per cent of our catalogue have WISE counterparts and are provided with classification from both models. We achieve 95.76 per cent (52.47 per cent) of quasar purity, 95.88 per cent (92.24 per cent) of quasar completeness, 99.44 per cent (98.17 per cent) of star purity, 98.22 per cent (78.56 per cent) of star completeness, 98.04 per cent (81.39 per cent) of galaxy purity, and 98.8 per cent (85.37 per cent) of galaxy completeness for the first (second) classifier, for which the metrics were calculated on objects with (without) WISE counterpart. A total of 2926 787 objects that are not in our spectroscopic sample were labelled, obtaining 335 956 quasars, 1347 340 stars, and 1243 391 galaxies. From those, 7.4 per cent, 76.0 per cent, and 58.4 per cent were classified with probabilities above 80 per cent. The catalogue with classification and probabilities for Stripe 82 S-PLUS DR2 is available for download. © 2021 The Author(s)., This work has been supported by a PhD fellowship to the lead author from Fundacao de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP), 2019/01312-2. LN also acknowledges the support of Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brasil (CAPES) -Finance Code 001 and FAPESP through process number 2014/10566-4. LN also thanks the staff of the Astronomy department from the University of Florida, where part of this work was done; Marco Antonio dos Santos and Ulisses Manzo Castello for the technical support; Luis Manrique for the technical support, feedback, and discussions about Machine Learning; Christian Massao Tsujiguchi Takagi and Vin ' icius Amaral Haga for the feedback on the accessibility of the figures in this paper; Gustavo Oliveira Schwarz for building the database. CMdO acknowledges funding from FAPESP through grants 2009/542028 and 2019/26492-3 and funding from the Brazilian National Research Council (CNPq), through grant 309209/2019-6. NSTH acknowledges FAPESP (grants 2017/25835-9 and 2015/22308-2). CQ acknowledges support from FAPESP (grants 2015/11442-0 and 2019/06766-1). AM acknowledges FAPESP scholarship grant 2018/25671-9. CEB acknowledges FAPESP, grant 2016/12331-0. FA-F acknowledges funding for this work from FAPESP grant 2018/20977-2. LSJ acknowledges support from Brazilian agencies FAPESP (2019/10923-5) and CNPq (304819/201794). AAC acknowledges support from Fundacao de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ; grant E26/203.186/2016) and CNPq (grants 304971/2016-2 and 401669/2016-5). EVL acknowledges funding for this work from CNPq grant 169181/2017-0 and CAPES grant 88887.470064/2019-00. MLB acknowledges FAPESP, grants 2018/09165-6 and 2019/23388-0. KMD acknowledges support from FAPERJ (grant E-26/203.184/2017), CNPq (grant 312702/2017-5) and the Serrapilheira Institute (grant Serra-1709-17357). AAC acknowledges support from FAPERJ (grant E26/203.186/2016), CNPq (grants 304971/2016-2 and 401669/2016-5), from the Universidad de Alicante under contract UATALENTO18-02, and from the State Agency for Research of the Spanish MCIU through the `Center of Excellence Severo Ochoa' award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). ARL acknowledges the financial support from CNPq through the PCI (Programa de Capacitacao Institucional) fellowship. The S-PLUS project, including the T80-South robotic telescope and the S-PLUS scientific survey, was founded as a partnership between FAPESP, the Observatorio Nacional (ON), the Federal University of Sergipe (UFS), and the Federal University of Santa Catarina (UFSC), with important financial and practical contributions from other collaborating institutes in Brazil, Chile (Universidad de La Serena), and Spain (Centro de Estudios de Física del Cosmos de Aragón, CEFCA). We further acknowledge financial support from FAPESP, CNPq, CAPES, FAPERJ, and the Brazilian Innovation Agency (FINEP).

The nearby Hydra Cluster ($\sim$50 Mpc) is an ideal laboratory to understand, in detail, the influence of the environment on the morphology and quenching of galaxies in dense environments. We study the Hydra cluster galaxies in the inner regions ($1R_{200}$) of the cluster using data from the Southern Photometric Local Universe Survey (S-PLUS), which uses 12 narrow and broad band filters in the visible region of the spectrum. We analyse structural (S\'ersic index, effective radius) and physical (colours, stellar masses and star formation rates) properties. Based on this analysis, we find that $\sim$88 percent of the Hydra cluster galaxies are quenched. Using the Dressler-Schectman test approach, we also find that the cluster shows possible substructures. Our analysis of the phase-space diagram together with DBSCAN algorithm indicates that Hydra shows an additional substructure that appears to be in front of the cluster centre, which is still falling into it. Our results, thus, suggest that the Hydra Cluster might not be relaxed. We analyse the median S\'ersic index as a function of wavelength and find that for red ($(u-r)\geq$2.3) and early-type galaxies it displays a slight increase towards redder filters (13 and 18 percent, for red and early-type respectively) whereas for blue+green ($(u-r)$, Comment: Accepted for publication in MNRAS

An exotic environment surrounds the young stellar groups associated with the Canis Major (CMa) OB1/R1 region, which probably was formed under feedback from at least three supernova events having occurred a few million years ago. We use astrometric data from the Gaia-DR2 to confirm the membership of the stars in CMa R1, based on proper motion and parallax, which revealed 514 new members and candidates. The mean age of 5 Myr estimated from the color-magnitude diagram characterizes the sources as likely pre-main sequence candidates. In total, a sample of 694 stars detected with the T80-South telescope was analyzed according to different color-color diagrams, which were compared with theoretical colors from evolutionary models, aiming to reveal the objects that exhibit color excess due to accretion processes. Accretion and magnetic activity were also explored on the basis of empirical flux-flux relation, such as F660 and F861 that are related to Halpha and Ca II triplet emission, respectively. A low fraction (3 percent) of the sample have Halpha excess and other colors expected for stars exhibiting chromospheric activity. The number of Class I and Class II objects, identified by the infrared (WISE) colors, indicates a disk fraction of 6 percent, which is lower than the expected for stellar clusters with similar age. A such large sample of objects associated with CMa R1 without evidences of circumstellar accretion can be interpreted as a lack of disk-bearing stars, unusual for young star-forming regions. However, this may be explained as the result of supernova events., Comment: 29 pages, 9 tables, 11 figures, accepted for publication in The Astronomical Journal

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 $\sim 330$ deg$^2$ 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., Instituto de Astrofísica de La Plata, Facultad de Ciencias Astronómicas y Geofísicas

The Southern Photometric Local Universe Survey (S-PLUS) is imaging similar to 9300 deg(2) of the celestial sphere in 12 optical bands using a dedicated 0.8mrobotic telescope, the T80-South, at the Cerro Tololo Inter-american Observatory, Chile. The telescope is equipped with a 9.2k x 9.2k e2v detector with 10 mu m pixels, resulting in a field of view of 2 deg(2) with a plate scale of 0.55 arcsec pixel-1. The survey consists of four main subfields, which include two non-contiguous fields at high Galactic latitudes (vertical bar b vertical bar > 30 degrees, 8000 deg(2)) and two areas of the Galactic Disc and Bulge (for an additional 1300 deg(2)). S-PLUS uses the Javalambre 12-band magnitude system, which includes the 5 ugriz broad-band filters and 7 narrow-band filters centred on prominent stellar spectral features: the Balmer jump/[OII], Ca H + K, Hd, G band, Mg b triplet, H alpha, and the Ca triplet. S-PLUS delivers accurate photometric redshifts (dz /(1 + z) = 0.02 or better) for galaxies with r < 19.7 AB mag and z < 0.4, thus producing a 3D map of the local Universe over a volume of more than 1 (Gpc/h)(3). The final S-PLUS catalogue will also enable the study of star formation and stellar populations in and around the Milky Way and nearby galaxies, as well as searches for quasars, variable sources, and low-metallicity stars. In this paper we introduce the main characteristics of the survey, illustrated with science verification data highlighting the unique capabilities of S-PLUS. We also present the first public data release of similar to 336 deg(2) of the Stripe 82 area, in 12 bands, to a limiting magnitude of r = 21, available at datalab.noao.edu/splus.© 2019 The Author(s).Published by Oxford University Press on behalf of the Royal Astronomical Society, The S-PLUS project, including the T80S robotic telescope and the S-PLUS scientific survey, was founded as a partnership between the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), the Observatorio Nacional (ON), the Federal University of Sergipe (UFS), and the Federal University of Santa Catarina (UFSC), with important financial and practical contributions from other collaborating institutes in Brazil, Chile (Universidad de La Serena), and Spain (Centro de Estudios de Fisica del Cosmos de Aragon, CEFCA). The members of the collaboration are grateful for the support received from the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq; grants 312333/2014-5, 306968/2014-2, 142436/2014-3, 459553/2014-3, 400738/2014-7, 302037/2015-2, 312307/2015-2, 300336/2016-0, 304184/2016-0, 304971/2016-2, 401669/2016-5, 308968/2016-6, 309456/2016-9, 421687/2016-9, 150237/2017-0, 311331/2017-3, 304819/2017-4, and 200289/2017-9), FAPESP (grants 2009/54202-8, 2011/51680-6, 2014/07684-5, 2014/11806-9, 2014/13723-3, 2014/18632-6, 2016/17119-9, 2016/12331-0, 2016/21532-9, 2016/21664-2, 2016/23567-4, 2017/01461-2, 2017/23766-0, 2018/02444-7, and 2018/21661-9), the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES; grants 88881.030413/2013-01 and 88881.156185/2017-01), the Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ; grants 202.876/2015, 202.835/2016, and 203.186/2016), the Financiadora de Estudos e Projetos (FINEP; grants 1217/13-01.13.0279.00 and 0859/10-01.10.0663.00), the Direccion de Investigacion y Desarrollo de la Universidad de La Serena (DIDULS/ULS; projects PR16143 and PTE16146 and the Programa de Investigadores Asociados), and the Direccion de Postgrado y Postitulo. TCB, VMP, and DDW acknowledge the support from the Physics Frontier Center for the Evolution of the Elements (JINA-CEE) through the US National Science Foundation (grant PHY 14-30152). JLNC is grateful for financial support received from the Southern Office of Aerospace Research and development (SOARD; grants FA9550-15-1-0167 and FA9550-18-1-0018) of the Air Force Office of the Scientific Research International Office of the United States (AFOSR/IO). YJT and RAD acknowledge support from the Spanish National Research Council (CSIC) I-COOP + 2016 program (grant COOPB20263), and the Spanish Ministry of Economy, Industry, and Competitiveness (MINECO; grants AYA2013-48623-C2-1-P and AYA2016-81065-C2-1-P). RAOM acknowledges support from the Direccion General de Asuntos del Personal Academico of the Universidad Nacional Autonoma de Mexico (DGAPA-UNAM) through a post-doctoral fellowship from the Programa de Becas Posdoctorales en la UNAM. This work has made use of data from the Sloan Digital Sky Survey. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Enenergy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is http://www.sdss.org/.The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), the New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington. This publication makes use of data products from the Widefield Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. We are grateful for the contributions of CTIO staff in helping in the construction, commissioning, and maintenance of the telescope and camera and we are particularly thankful to the CTIO director, Steve Heathcote, for his support at every phase, without which this project would not have been completed. We thank Cesar Iniguez for making the 2D measurements of the filter transmissions at CEFCA. We warmly thank David Cristobal-Hornillos and his group for helping us to install and run the reduction package JYPE version 0.9.9 in the S-PLUS computer system in Chile. We warmly thank Mariano Moles, Javier Cenarro, Tamara Civera, Sergio Chueca, Javier Hernandez Fuertes, Antonio Marin Franch, Jesus Varella, and Hector Vazquez Ramio -the success of the S-PLUS project relies on the dedication of these and other CEFCA staff members in building OAJ and running J-PLUS and J-PAS. We deeply thank Rene Laporte and INPE, as well as Keith Taylor, for their contributions to the T80S camera.

Context. Bright stellar positions are now known with an uncertainty below 1 mas thanks to Gaia DR2. Between 2019-2020, the Galactic plane will be the background of Jupiter. The dense stellar background will lead to an increase in the number of occultations, while the Gaia DR2 catalogue will reduce the prediction uncertainties for the shadow path. Aims. We observed a stellar occultation by the Galilean moon Europa (J2) and propose a campaign for observing stellar occultations for all Galilean moons. Methods. During a predicted period of time, we measured the light flux of the occulted star and the object to determine the time when the flux dropped with respect to one or more reference stars, and the time that it rose again for each observational station. The chords obtained from these observations allowed us to determine apparent sizes, oblatness, and positions with kilometre accuracy. Results. We present results obtained from the first stellar occultation by the Galilean moon Europa observed on 2017 March 31. The apparent fitted ellipse presents an equivalent radius of 1561.2 $\pm$ 3.6 km and oblatenesses 0.0010 $\pm$ 0.0028. A very precise Europa position was determined with an uncertainty of 0.8 mas. We also present prospects for a campaign to observe the future events that will occur between 2019 and 2021 for all Galilean moons. Conclusions. Stellar occultation is a suitable technique for obtaining physical parameters and highly accurate positions of bright satellites close to their primary. A number of successful events can render the 3D shapes of the Galilean moons with high accuracy. We encourage the observational community (amateurs included) to observe the future predicted events., Comment: 10 pages, 16 figures, 4 tables, A&A Letter doi:10.1051/0004-6361/201935500

We report on the discovery of SPLUS J210428.01-004934.2, an ultra metal-poor (UMP) star first identified from the narrow-band photometry of the Southern Photometric Local Universe Survey (S-PLUS) Data Release 1, in the SDSS Stripe 82 region. Follow-up medium- and high-resolution spectroscopy (with Gemini South and Magellan-Clay, respectively) confirmed the effectiveness of the search for low-metallicity stars using the S-PLUS narrow-band photometry. At [Fe/H]=-4.03, SPLUS J2104-0049 has the lowest detected carbon abundance, A(C)=+4.34, when compared to the 34 previously known UMP stars in the literature, which is an important constraint on its stellar progenitor and also on stellar evolution models at the lowest metallicities. Based on its chemical abundance pattern, we speculate that SPLUS J2104-0049 could be a bonafide second-generation star, formed from a gas cloud polluted by a single metal-free ~30Mo star. This discovery opens the possibility of finding additional UMP stars directly from narrow-band photometric surveys, a potentially powerful method to help complete the inventory of such peculiar objects in our Galaxy., Comment: 10 pages, 3 figures, accepted for publication on ApJ Letters

Aims. We aim to use multiband imaging from the Phase-3 Verification Data of the J-PLUS survey to derive accurate photometric redshifts (photo-z) and look for potential new members in the surroundings of the nearby galaxy clusters A2589 (z = 0.0414) & A2593 (z = 0.0440), using redshift probability distribution functions (PDFs). The ultimate goal is to demonstrate the usefulness of a 12-band filter system in the study of largescale structure in the local Universe. Methods. We present an optimized pipeline for the estimation of photometric redshifts in clusters of galaxies. This pipeline includes a PSF-corrected photometry, specific photometric apertures capable of enhancing the integrated signal in the bluest filters, a careful recalibration of the photometric uncertainties and accurate upper-limit estimations for faint detections. To foresee the expected precision of our photo-z beyond the spectroscopic sample, we designed a set of simulations in which real cluster galaxies are modeled and reinjected inside the images at different signal-to-noise ratio (S/N) levels, recomputing their photometry and photo-z estimates. Results. We tested our photo-z pipeline with a sample of 296 spectroscopically confirmed cluster members with an averaged magnitude of (r) = 16.6 and redshift (z) = 0.041. The combination of seven narrow and five broadband filters with a typical photometric-depth of r ∼ 21.5 provides δ z /(1 + z) = 0.01 photo-z estimates. A precision of δ z /(1 + z) = 0.005 is obtained for the 177 galaxies brighter than magnitude r < 17. Based on simulations, a δ z /(1 + z) = 0.02 and δ z /(1 + z) = 0.03 is expected at magnitudes (r) = 18 and (r) = 22, respectively. Complementarily, we used SDSS/DR12 data to derive photo-z estimates for the same galaxy sample. This exercise demonstrates that the wavelength-resolution of the J-PLUS data can double the precision achieved by SDSS data for galaxies with a high S/N. Based on the Bayesian membership analysis carried out in this work, we find as much as 170 new candidates across the entire field (∼5 deg 2 ). The spatial distribution of these galaxies may suggest an overlap between the systems with no evidence of a clear filamentary structure connecting the clusters. This result is supported by X-ray Rosat All-Sky Survey observations suggesting that a hypothetical filament may have low density contrast on diffuse warm gas. Conclusions. We prove that the addition of the seven narrow-band filters make the J-PLUS data deeper in terms of photo-z-depth than other surveys of a similar photometric-depth but using only five broadbands. These preliminary results show the potential of J-PLUS data to revisit membership of groups and clusters from nearby galaxies, important for the determination of luminosity and mass functions and environmental studies at the intermediate and low-mass regime. © ESO 2019., Funding for the J-PLUS Project has been provided by the Governments of Spain and Aragon through the Fondo de Inversiones de Teruel, the Aragon Government through the Reseach Groups E96 and E103, the Spanish Ministry of Economy and Competitiveness (MINECO; under grants AYA2015-66211-C2-1-P, AYA2015-66211-C2-2, AYA2012-30789 and ICTS-2009-14), and European FEDER funding (FCDD10-4E-867, FCDD13-4E-2685). AM acknowledges the financial support of the Brazilian funding agency FAPESP (Post-doc fellowship -process number 2014/11806-9). MVCD thanks his scholarship from FAPESP (processes 2014/18632-6 and 2016/05254-9). CMdO and other Brazilian collaborators acknowledge funding from FAPESP through grants 2009/54202-8 and 2011/51680-6. WAS would like to acknowledge technical training fellowship number 2016/06484-8 from FAPESP and post-doc fellowship project 400247/2014-3 from the Brazilian funding agency CNPq. LSJr would like to acknowledge FAPESP for the fellowship number 2012/00800-4. J.A.H.J. thanks to Brazilian institution CNPq for financial support through postdoctoral fellowship (project 150237/2017-0). EP acknowledges the Brazilian institution CNPq for the financial support through the technical training fellowship (project 155666/2016-9). ESC acknowledges financial support from Brazilian agencies CNPQ and FAPESP (process number 2014/13723-3). Y.J-T. acknowledges the financial support from the Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro - FAPERJ (fellowship Nota 10, PDR-10). We acknowledge the economical support from the Spanish Ministerio de Educacion y Ciencia through grant AYA2006-14056 BES-2007-16280, AYA2012-30789, AYA2015-66211-C2-1-P and AYA2015-66211-C2-2.

We investigate the cosmic evolution of the absolute and specific star formation rate (SFR, sSFR) of galaxies as derived from a spatially resolved study of the stellar populations in a set of 366 nearby galaxies from the Calar Alto Legacy Integral Field Area (CALIFA) survey. The sample spans stellar masses from M ∼ 10 to 10M and a wide range of Hubble types. The analysis combines images obtained with the Galaxy Evolution Explorer (GALEX; far-ultraviolet and near-ultraviolet) and Sloan Digital Sky Survey (SDSS; u; g; r; i; z) with the 4000 Å break, Hβ, and [MgFe]′ indices measured from the CALIFA data cubes to constrain parametric models for the star formation history (SFH), which are then used to study the cosmic evolution of the SFR density (ρSFR), the sSFR, the main sequence of star formation (MSSF), and the stellar mass density (ρ). Several SFH laws are used to fit the observational constrains. A delayed-τ model, SFR ∝ (t - t) exp(-(t - t)=τ), provides the best results, in good agreement with those obtained from cosmological surveys. Our main results from this model are that (a) the mass currently in the inner (≤0:5 half-light radius, HLR) regions formed at earlier epochs than the mass in the outer (1-2 HLR) regions of galaxies. The time since the onset of the star formation is longer in the inner regions (t ∼ 13-10 Gyr) than in the outer ones (t ∼ 11-9 Gyr) for all the morphologies, while the e-folding timescale τ in the inner region is similar to or shorter than in the outer regions. These results confirm that galaxies of any Hubble type grow inside-out. (b) The sSFR declines rapidly as the Universe evolves, and faster for early- than for late-type galaxies, and for the inner than for the outer regions of galaxies. (c) The evolution of ρSFR and ρ agrees well with results from cosmological surveys, particularly with the recent results from the Galaxy And Mass Assembly (GAMA), the G10-Cosmological Evolution Survey (COSMOS), and the 3D Hubble Space Telescope (HST) survey. At low redshift, z ≤ 0:5, most star formation takes place in the outer regions of late spiral galaxies, while at z > 2; the inner regions of the progenitors of the current E and S0 are the main contributors to ρSFR. (d) Similarly, the inner regions of galaxies are the main contributor to ρ at z > 0:5, growing their mass faster than the outer regions, with a lookback time at 50% ρ of t ∼ 9 and 6 Gyr for the inner and outer regions. (e) The MSSF follows a power law at high redshift, with the slope evolving with time but always remaining sub-linear, in good agreement with the Illustris simulation. (f) In agreement with galaxy surveys at different redshifts, the average SFH of CALIFA galaxies indicates that galaxies grow their mass mainly in a mode that is well represented by a delayed-τ model, with the peak at z ∼ 2 and an e-folding time of ∼3:9 Gyr.© 2018 ESO., Support from the Spanish Ministerio de Economía y Competitividad, through projects AYA2016-77846-P, AYA2014-57490-P, AYA2010-15081, and the Junta de Andalucía FQ1580 is gratefully acknowledged.

We present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration (TOROS). We detected highly significant dimming in the light curves of the counterpart (Delta g=0.17+-0.03 mag, Delta r=0.14+-0.02 mag, Delta i=0.10 +- 0.03 mag) over the course of only 80 minutes of observations obtained ~35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ~59 hr after the event with the EABA 1.5m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a "blue kilonova" relatively free of lanthanides., Accepted for publication in The Astrophysical Journal Letters

Context. From the approximately 3500 planetary nebulae (PNe) discovered in our Galaxy, only 14 are known to be members of the Galactic halo. Nevertheless, a systematic search for halo PNe has never been performed. Aims. In this study, we present new photometric diagnostic tools to identify compact PNe in the Galactic halo by making use of the novel 12-filter system projects, Javalambre Photometric Local Universe Survey (J-PLUS) and Southern-Photometric Local Universe Survey (S-PLUS). Methods. We reconstructed the Isaac Newton Telescope Photometric H alpha Survey of the Northern Galactic Plane diagnostic diagram and propose four new ones using (i) the J-PLUS and S-PLUS synthetic photometry for a grid of photo-ionisation models of halo PNe, (ii) several observed halo PNe, as well as (iii) a number of other emission-line objects that resemble PNe. All colour-colour diagnostic diagrams are validated using two known halo PNe observed by J-PLUS during the scientific verification phase and the first data release (DR1) of S-PLUS and the DR1 of J-PLUS. Results. By applying our criteria to the DR1s (similar to 1190 deg(2)), we identified one PN candidate. However, optical follow-up spectroscopy proved it to be a HII region belonging to the UGC 5272 galaxy. Here, we also discuss the PN and two HII galaxies recovered by these selection criteria. Finally, the cross-matching with the most updated PNe catalogue (HASH) helped us to highlight the potential of these surveys, since we recover all the known PNe in the observed area. Conclusions. The tools here proposed to identify PNe and separate them from their emission-line contaminants proved to be very efficient thanks to the combination of many colours, even when applied - like in the present work - to an automatic photometric search that is limited to compact PNe. © ESO 2020, The authors acknowledge anonymous referee for very insightful comments and for helping us to significantly improve our paper. We thank J.A. Caballero and R. Lopes de Oliveira for their useful comments and suggestions. L.A.G.S. acknowledges the support of CAPES-the Brazilian Federal Agency for Support and Evaluation of Graduate Education within the Ministry of Education of Brazil. D.R.G. thanks the partial support of CNPq (grant 304184/2016-0) and S.A. acknowledges CAPES for a fellowship from the National Postdoctoral Program (PNPD). L.G. was funded by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 839090. R.L.O. was partially supported by the Brazilian agency CNPq (PQ 302037/2015-2). This work is based on observations made with the JAST/T80 telescope at the Observatorio Astrofisico de Javalambre (OAJ), in Teruel, owned, managed and operated by the Centro de Estudios de Fisica del Cosmos de Aragon. Funding for the J-PLUS Project has been provided by the Governments of Spain and Aragon throug the Fondo de Inversiones de Teruel, the Spanish Ministry of Economy and Competitiveness (MINECO: under grants AYA2015-66211-C2-1-P, AYA2015-66211-C2-2, AYA2012-30789 and ICTS-2009-14), and European FEDER funding (FCDD10-4E-867, FCDD13-4E-2685). The Brazilian agencies FAPESP and the National Observatory of Brazil have also contributed to this project. We acknowledge the OAJ Data Processing and Archiving Unit (UPAD) for reducing and calibrating the OAJ data used in this work. This study used data collected at the T80-South, a new 0.826 m telescope carried out by S-PLUS project. The T80-South robotic telescope (Mendes de Oliveira et al. 2019) was founded as a partnership between the Sao Paulo Research Foundation (FAPESP), the Observatorio Nacional (ON), the Federal University of Sergipe (UFS) and the Federal University of Santa Catarina (UFSC), with important financial and practical contributions from other collaborating institutes in Brazil, Chile (Universidad de La Serena) and Spain (CEFCA). We want to thank to the S-PLUS team for the reducing and calibrating of the data. This research has made use of the HASH PN database at hashpn.space. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofisica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, the Korean Participation Group, Lawrence Berkeley National Laboratory, Leibniz Institut fur Astrophysik Potsdam (AIP), Max-Planck-Institut fur Astronomie (MPIA Heidelberg), Max-Planck-Institut fur Astrophysik (MPA Garching), Max-Planck-Institut fur Extraterrestrische Physik (MPE), National Astronomical Observatories of China, New Mexico State University, New York University, University of Notre Dame, Observatario Nacional / MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autonoma de Mexico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University.

We present accurate photometric redshifts for galaxies observed by the Cluster Lensing And Supernova survey with Hubble (CLASH). CLASH observed 25 massive galaxy cluster cores with the Hubble Space Telescope in 16 filters spanning 0.2-1.7 μm. Photometry in such crowded fields is challenging. Compared to our previously released catalogues, we make several improvements to the photometry, including smaller apertures, intracluster light subtraction, point spread function matching and empirically measured uncertainties. We further improve the Bayesian photometric redshift estimates by adding a redder elliptical template and by inflating the photometric uncertainties of the brightest galaxies. The resulting photometric redshift accuracies are dz/(1+z) ~ 0.8, 1.0 and 2.0 per cent for galaxies with I-band F814W AB magnitudes < 18, 20 and 23, respectively. These results are consistent with our expectations. They improve on our previously reported accuracies by a factor of 4 at the bright end and a factor of 2 at the faint end. Our new catalogue includes 1257 spectroscopic redshifts, including 382 confirmed cluster members. We also provide stellar mass estimates. Finally, we include lensing magnification estimates of background galaxies based on our public lens models. Our new catalogue of all 25 CLASH clusters is available via Mikulski Archive for Space Telescopes. The analysis techniques developed here will be useful in other surveys of crowded fields, including the Frontier Fields and surveys carried out with Javalambre-Physics of the Accelerated Universe Astrophysical Survey and James Webb Space Telescope.© 2017 The Authors., We acknowledge the financial support of the Brazilian funding agency FAPESP (Post-doc fellowship - process number 2014/11806-9). Likewise, we also acknowledge the Spanish Ministerio de Educacion y Ciencia through grant AYA2006-14056 BES-2007-16280. We acknowledge the financial support from the Spanish MICINN under the Consolider-Ingenio 2010 Program grant CSD2006-00070: First Science with the GTC. AM acknowledges the CEFCA (Centro de Estudios de Fisica del Cosmos de Aragon) and the IAA-CSIC (Instituto de Astrofisica de Andalucia) institutes for hosting him during the period 2015/2016. PR, MM, AMe and MN acknowledge the financial support from PRIN-INAF 2014 1.05.01.94.02. Likewise, AMacknowledges the STScI (Space Telescope Science Institute) for hosting him during 2010 AugustSeptember, 2011 June-August and 2016 July. We acknowledge the financial support of ESO since most of the spectroscopic redshifts used in the work were based on ESO VLT programme ID 186.A-0798. BA has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 656354.

This work presents the properties of 42 objects in the group of the most luminous, highest star formation rate (SFR) low-ionization nuclear emission-line regions (LINERs) at z = 0.04-0.11. We obtained long-slit spectroscopy of the nuclear regions for all sources, and FIR data (Herschel and IRAS) for 13 of them. We measured emission-line intensities, extinction, stellar populations, stellarmasses, ages, active galactic nuclei (AGN) luminosities, and SFRs. We find considerable differences from other low-redshift LINERs, in terms of extinction, and general similarity to star-forming galaxies. We confirm the existence of such luminous LINERs in the local universe, after being previously detected at z ~0.3 by Tommasin et al. Themedian stellar mass of these LINERs corresponds to 6-7 × 1010 M⊙ which was found in previous work to correspond to the peak of relative growth rate of stellar populations and therefore for the highest SFRs. Other LINERs although showing similar AGN luminosities have lower SFR. We find that most of these sources have LAGN ~ LSF suggesting co-evolution of black hole and stellarmass. In general, the fraction of local LINERs on themain sequence of star-forming galaxies is related to their AGN luminosity. © 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society., This research was supported by the Junta de Andalucia through project TIC114, and the Spanish Ministry of Economy and Competitiveness (MINECO) through project AYA2013-42227-P. The work was also supported by the Israel Science Foundation grant 284/13. MP acknowledge financial support from JAE-Doc programme of the Spanish National Research Council (CSIC), co-funded by the European Social Fund.

A numerous population of weak line galaxies (WLGs) is often left out of statistical studies on emission line galaxies (ELGs) due to the absence of an adequate classification scheme, since classical diagnostic diagrams, like [OIII]/Hb vs [NII]/Ha (the BPT diagram), require the measurement of at least 4 emission lines. This paper aims to remedy this situation by transposing the usual divisory lines between Star Forming (SF) and AGN hosts, and between Seyferts and LINERs to diagrams that are more economical in terms of line quality requirements. By doing this, we rescue from the classification limbo a substantial number of sources and modify the global census of ELGs. More specifically: (1) We use the SDSS DR7 to constitute a suitable sample of 280k ELGs, 1/3 of which are WLGs. (2) Galaxies with strong emission lines are classified using the widely applied criteria of Kewley et al (2001), Kauffmann et al (2003), Stasinska et al (2006) and Kewley et al (2006). (3) We transpose these classification schemes to alternative diagrams keeping [NII]/Ha as a horizontal axis, but replacing Hb by a stronger line (Ha or [OII]), or substituting [OIII]/Hb ratio with the equivalent width of Ha. Optimized equations for the transposed divisory lines are provided. (4) We show that nothing significant is lost in the translation, but that the new diagrams allow one to classify up to 50% more ELGs. (5) Introducing WLGs in the census of galaxies in the local Universe increases the proportion of metal-rich SF galaxies and especially LINERs. (abridged)

Massive spectroscopic surveys like the SDSS have revolutionized the way we study AGN and their relations to the galaxies they live in. A first step in any such study is to define samples of different types of AGN on the basis of emission line ratios. This deceivingly simple step involves decisions on which classification scheme to use and data quality censorship. Galaxies with weak emission lines are often left aside or dealt with separately because one cannot fully classify them onto the standard Star-Forming, Seyfert of LINER categories. This contribution summarizes alternative classification schemes which include this very numerous population. We then study how star-formation histories and physical properties of the hosts vary from class to class, and present compelling evidence that the emission lines in the majority of LINER-like systems in the SDSS are not powered by black-hole accretion. The data are fully consistent with them being galaxies whose old stars provide all the ionizing power needed to explain their line ratios and luminosities. Such retired galaxies deserve a place in the emission line taxonomy., Comment: 8 pages, 4 figures, Proceedings of IAU Symposium 267, Co-Evolution of Central Black Holes and Galaxies

The impending Javalambre Physics of the accelerating Universe Astrophysical Survey (J-PAS) will be the first wide-field survey of ≳ 8500 deg2 to reach the 'stage IV' category. Because of the redshift resolution afforded by 54 narrow-band filters, J-PAS is particularly suitable for cluster detection in the range z80 per cent completeness and purity is M ~ 5 × 10M⊙ up to z ~ 0.7. We also model the optical observable, M-halo mass relation, finding a non-evolution with redshift and main scatter of σM|M ~ 0.14 dex down to a factor 2 lower in mass than other planned broad-band stage IV surveys, at least. For the M ~ 1 × 10M⊙ Planck mass limit, J-PAS will arrive up to z ~ 0.85 with a σM|M ~ 0.12 dex. Therefore, J-PAS will provide the largest sample of clusters and groups up to z ~ 0.8 with a mass calibration accuracy comparable to X-ray data. © 2016 The Authors., EC, GLN, CMdO, AM and LS acknowledge funding from PAPESP and CNPq. IO acknowledges support from the European Research Council (ERC) in the form of Advanced Grant, COSMICISM. We acknowledge support from the Spanish Ministry for Economy and Competitiveness through grants ilink0862 and AYA2013-48623-C02-1-P.

We study the evolution of 82302 star-forming (SF) galaxies from the SDSS. Our main goals are to explore new ways of handling star formation histories (SFH) obtained with our publicly available spectral synthesis code STARLIGHT, and apply them to investigate how SFHs vary as a function of nebular metallicity (Zneb). Our main results are: (1) A conventional correlation analysis shows how global properties such as luminosity, mass, dust content, mean stellar metallicity and mean stellar age relate to Zneb. (2) We present a simple formalism which compresses the results of the synthesis into time-dependent star formation rates (SFR) and mass assembly histories. (3) The current SFR derived from the population synthesis and that from H-alpha are shown to agree within a factor of two. Thus we now have a way to estimate SFR in AGN hosts, where the H-alpha method cannot be applied. (4) Fully time-dependent SFHs are derived for all galaxies and averaged over six Zneb bins spanning the entire SF wing in the [OIII]/H-beta X [NII]/H-alpha diagram. (5) We find that SFHs vary systematically along the SF sequence, such that low-Zneb systems evolve slower and are currently forming stars at a higher relative rate. (6) At any given time, the distribution of specific SFRs for galaxies within a Zneb-bin is broad and roughly log-normal. (7) The same results are found grouping galaxies in stellar mass (M*) or surface mass density (S*) bins. (8) The overall pattern of SFHs as a function of Zneb, M* or S* is robust against changes in selection criteria, choice of evolutionary synthesis models for the spectral fits, and differential extinction effects. (Abridged), Accepted for publication in MNRAS

Ascaso, Begoña et al., We present a catalogue of 348 galaxy clusters and groups with 0.2 < z < 1.2 selected in the 2.78 deg2 Advanced Large, Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) survey. The high precision of our photometric redshifts, close to 1 per cent, and the wide spread of the seven ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and is less affected by cosmic variance than comparable samples. The detection has been carried out with the Bayesian Cluster Finder, whose performance has been checked in ALHAMBRA-like light-cone mock catalogues. Great care has been taken to ensure that the observable properties of the mocks photometry accurately correspond to those of real catalogues. From our simulations, we expect to detect galaxy clusters and groups with both 70 per cent completeness and purity down to dark matter halo masses of Mh ∼ 3 × 1013 M⊙ for z < 0.85. Cluster redshifts are expected to be recovered with ∼0.6 per cent precision for z < 1. We also expect to measure cluster masses with σMh|M∗CL∼0.25-0.35dexσMh|MCL∗∼0.25-0.35dex precision down to ∼ 3 × 1013 M⊙, masses which are 50 per cent smaller than those reached by similar work. We have compared these detections with previous optical, spectroscopic and X-rays work, finding an excellent agreement with the rates reported from the simulations. We have also explored the overall properties of these detections such as the presence of a colour–magnitude relation, the evolution of the photometric blue fraction and the clustering of these sources in the different ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that, for a fixed stellar mass, the environment is playing a crucial role at lower redshifts (z < 0.5)., We acknowledge support from the Spanish Ministry for Economy and Competitiveness and FEDER funds through grants AYA2010-22111-C03-02, AYA2010-15169, AYA2012-30789, AYA2013-48623-C2-2, AYA2013-42227-P, AYA2013-40611-P, AYA2011-29517-C03-01, AYA2014-58861-C3-1, AYA2010-15081, Generalitat Valenciana projects PROMETEOII/2014/060, Junta de Andalucia grant TIC114, JA2828, Aragon Gorvernment-Research Group E103. MP acknowledges financial support from JAE-Doc program of the Spanish National Research Council (CSIC), co-funded by the European Social Fund. PAM acknowledges support from ERC StG Grant DEGAS-259586 and from the Science and Technology Facilities Council grants ST/K003305/1 and ST/L00075X/1.

We report the results of two multi-chord stellar occultations by the dwarf planet (1) Ceres that were observed from Brazil on 2010 August 17, and from the USA on 2013 October 25. Four positive detections were obtained for the 2010 occultation, and nine for the 2013 occultation. Elliptical models were adjusted to the observed chords to obtain Ceres' size and shape. Two limb fitting solutions were studied for each event. The first one is a nominal solution with an indeterminate polar aspect angle. The second one was constrained by the pole coordinates as given by Drummond et al. Assuming a Maclaurin spheroid, we determine an equatorial diameter of 972 $\pm$ 6 km and an apparent oblateness of 0.08 $\pm$ 0.03 as our best solution. These results are compared to all available size and shape determinations for Ceres made so far, and shall be confirmed by the NASA's Dawn space mission., 9 pages, 6 figures. Accepted for publication in MNRAS

We revisit the bimodal distribution of the galaxy population commonly seen in the local universe. Here we address the bimodality observed in galaxy properties in terms of spectral synthesis products, such as mean stellar ages and stellar masses, derived from the application of this powerful method to a volume-limited sample, with magnitude limit cutoff M_r = -20.5, containing about 50 thousand luminous galaxies from the SDSS Data Release 2. In addition, galaxies are classified according to their emission line properties in three distinct spectral classes: star-forming galaxies, with young stellar populations; passive galaxies, dominated by old stellar populations; and, hosts of active nuclei, which comprise a mix of young and old stellar populations. We show that the extremes of the distribution of some galaxy properties, essentially galaxy colours, 4000 A break index, and mean stellar ages, are associated to star-forming galaxies at one side, and passive galaxies at another. We find that the mean light-weighted stellar age of galaxies is the direct responsible for the bimodality seen in the galaxy population. The stellar mass, in this view, has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results also give support to the existence of a 'downsizing' in galaxy formation, where massive galaxies seen nowadays have stellar populations formed at early times., 18 pages, 19 figures, accepted for publication in MNRAS

A. Molino et al., The Advance Large Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) survey has observed eight different regions of the sky, including sections of the Cosmic Evolution Survey (COSMOS), DEEP2, European Large-Area Infrared Space Observatory Survey (ELAIS), Great Observatories Origins Deep Survey North (GOODS-N), Sloan Digital Sky Survey (SDSS) and Groth fields using a new photometric system with 20 optical, contiguous ~300-Å filters plus the JHKs bands. The filter system is designed to optimize the effective photometric redshift depth of the survey, while having enough wavelength resolution for the identification of faint emission lines. The observations, carried out with the Calar Alto 3.5-m telescope using the wide-field optical camera Large Area Imager for Calar Alto (LAICA) and the near-infrared (NIR) instrument Omega-2000, represent a total of ~700 h of on-target science images. Here we present multicolour point-spread function (PSF) corrected photometry and photometric redshifts for ~438 000 galaxies, detected in synthetic F814W images. The catalogues are complete down to a magnitude I~24.5AB and cover an effective area of 2.79 deg2. Photometric zero-points were calibrated using stellar transformation equations and refined internally, using a new technique based on the highly robust photometric redshifts measured for emission-line galaxies. We calculate Bayesian photometric redshifts with the Bayesian Photometric Redshift (BPZ)2.0 code, obtaining a precision of δz/(1+zs)=1 per cent for I, We acknowledge financial support from the Spanish MICINN under the Consolider-Ingenio 2010 Program grant CSD2006-00070: First Science with the GTC. Part of this work was supported by Junta de Andalucía, through grant TIC-114 and the Excellence Project P08-TIC-3531, and by the Spanish Ministry for Science and Innovation through grants AYA2006-1456, AYA2010-15169, AYA2010-22111-C03-02, AYA2010-22111-C03-01 and Generalitat Valenciana project Prometeo 2009/064.

We have obtained the mass-metallicity (M-Z) relation at different lookback times for the same set of galaxies from the Sloan Digital Sky Survey, using the stellar metallicities estimated with our spectral synthesis code STARLIGHT. We have found that this relation steepens and spans a wider range in both mass and metallicity at higher redshifts. We have modeled the time evolution of stellar metallicity with a closed-box chemical evolution model, for galaxies of different types and masses. Our results suggest that the M-Z relation for galaxies with present-day stellar masses down to 10^10 M_sun is mainly driven by the history of star formation history and not by inflows or outflows., Accepted for publication in MNRAS

During the last three decades, many papers have reported the existence of a luminosity-metallicity or mass-metallicity (M-Z) relation for all kinds of galaxies: The more massive galaxies are also the ones with more metal-rich interstellar medium. We have obtained the mass-metallicity relation at different lookback times for the same set of galaxies from the Sloan Digital Sky Survey (SDSS), using the stellar metallicities estimated with our spectral synthesis code STARLIGHT. Using stellar metallicities has several advantages: We are free of the biases that affect the calibration of nebular metallicities; we can include in our study objects for which the nebular metallicity cannot be measured, such as AGN hosts and passive galaxies; we can probe metallicities at different epochs of a galaxy evolution. We have found that the M-Z relation steepens and spans a wider range in both mass and metallicity at higher redshifts for SDSS galaxies. We also have modeled the time evolution of stellar metallicity with a closed-box chemical evolution model, for galaxies of different types and masses. Our results suggest that the M-Z relation for galaxies with present-day stellar masses down to 10^10 solar masses is mainly driven by the star formation history and not by inflows or outflows., Comment: To appear in the proceedings of IAU symposium 262, 'Stellar Populations - Planning for the Next Decade'

We explore the mass-assembly and chemical enrichment histories of star forming galaxies by applying a population synthesis method to a sample of 84828 galaxies from the Sloan Digital Sky Survey Data Release 5. Our method decomposes the entire observed spectrum in terms of a sum of simple stellar populations spanning a wide range of ages and metallicities, thus allowing the reconstruction of galaxy histories. A comparative study of galaxy evolution is presented, where galaxies are grouped onto bins of nebular abundances or mass. We find that galaxies whose warm interstellar medium is poor in heavy elements are slow in forming stars. Their stellar metallicities also rise slowly with time, reaching their current values ($Z_\star \sim 1/3 Z_\odot$) in the last $\sim 100$ Myr of evolution. Systems with metal rich nebulae, on the other hand, assembled most of their mass and completed their chemical evolution long ago, reaching $Z_\star \sim Z_\odot$ already at lookback times of several Gyr. These same trends, which are ultimately a consequence of galaxy downsizing, appear when galaxies are grouped according to their stellar mass. The reconstruction of galaxy histories to this level of detail out of integrated spectra offers promising prospects in the field of galaxy evolution theories., Comment: Accepted for publication in MNRAS

This project consists in mapping a 4-square-degree region searching for exoplanets using the transit method. This “mini-survey” will be the first use of the 16″ robotic telescope developed by Universidade Federal de Santa Catarina (UFSC-Brazil) and Laboratório Nacional de Astrofísica (LNA/MCT-Brazil). The chosen region is over the Columba constellation and our first observations have shown that we have enough signal-to-noise ratio to search for transits on about 20,000 stars with ~13 < I < 16 mag, a magnitude range between the OGLE and HAT projects. In this star sample we expect to find about a dozen planets with transits duration of 1-3 hours and magnitude depth from 0.001 to 0.010 mag. As for other projects, all information will became public as a VO service.

We present results derived from the first multi-chord stellar occultations by the transneptunian object (50000) Quaoar, observed on 2011 May 4 and 2012 February 17, and from a single-chord occultation observed on 2012 October 15. If the timing of the five chords obtained in 2011 were correct, then Quaoar would possess topographic features (crater or mountain) that would be too large for a body of this mass. An alternative model consists in applying time shifts to some chords to account for possible timing errors. Satisfactory elliptical fits to the chords are then possible, yielding an equivalent radius Requiv = 555±2.5 km and geometric visual albedo pV = 0.109±0.007. Assuming that Quaoar is a Maclaurin spheroid with an indeterminate polar aspect angle, we derive a true oblateness of = 0.087+0.0268 −0.0175, an equatorial radius of 569+24 −17 km, and a density of 1.99 ± 0.46 g cm−3. The orientation of our preferred solution in the plane of the sky implies that Quaoar’s satellite Weywot cannot have an equatorial orbit. Finally, we detect no global atmosphere around Quaoar, considering a pressure upper limit of about 20 nbar for a pure methane atmosphere. Fil: Braga Ribas, F.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil; . Laboratoire d; Fil: Sicardy, B.. Laboratoire d; . Universite Pierre Et Marie Curie; Francia; Fil: Ortiz, J. L.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; Fil: Lellouch, E.. Laboratoire d; Fil: Tancredi, G.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Lecacheux, J.. Laboratoire d; Fil: Vieira Martins, R.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil; . L; . Universidade Federal Rural do Rio de Janeiro. Observatorio do Valongo; Brasil; Fil: Camargo, J. I. B.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil; Fil: Assafin, M.. Universidade Federal Rural do Rio de Janeiro. Observatorio do Valongo; Brasil; Fil: Behrend, R.. Observatoire de Geneve; Suiza; Fil: Vachier, F.. L; Fil: Colas, F.. L; Fil: Morales, N.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; Fil: Maury, A.. San Pedro de Atacama Celestial Explorations, Chile; Fil: Emilio, M.. Universidad Stadual de Ponta Grossa; Brasil; Fil: Amorim, A.. Universidade Federal Da Santa Catarina; Brasil; Fil: Unda Sanzana, E.. Universidad de Antofagasta. Unidad de Astronomía; Chile; Fil: Roland, S.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Bruzzone, S.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Almeida, L. A.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Rodrigues, C. V.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Jacques, C.. Centro de Estudos Astronomicos de Minas Gerais; Brasil; Fil: Gil Hutton, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - San Juan. Complejo Astronómico; Argentina Fil: Vanzi, L.. Pontificia Universidad Católica de Chile. Department of Electrical Engineering and Center of Astro-Engineering; Chile; Fil: Milone, A. C.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Schoenell, W.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; . Universidade Federal Da Santa Catarina; Brasil; Fil: Salvo, R.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Almenares, L.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Jehin, E. Université de Liège. Institut d’Astrophysique; Belgica; Fil: Manfroid, J.. Université de Liège. Institut d’Astrophysique; Belgica; Fil: Sposetti, S.. Gnosca Observatory, Suiza; Fil: Tanga, P.. Observatoire de la Cote D; . Universite de Sophia Antipolis. Laboratoire Lagrange; Francia; Fil: Klotz, A.. Université Toulouse III “Paul Sabatier”. Observatoire Midi-Pyrénées. Institut de Recherche en Astrophysique et Planétologie; Francia; Fil: Frappa, E.. Euraster, Francia; Fil: Cacella, P.. Rede de Astronomia Observacional; Brasil; Fil: Colque, J. P.. Universidad de Antofagasta. Unidad de Astronomía; Chile; Fil: Neves, C.. Universidad Stadual de Ponta Grossa; Brasil; Fil: Alvarez, E. M.. Observatorio Los Algarrobos, Uruguay; Fil: Gillon, M.. Université de Liège. Institut d’Astrophysique; Belgica; Fil: Pimentel, E.. Centro de Estudos Astronomicos de Minas Gerais; Brasil; Fil: Giacchini, B.. Centro de Estudos Astronomicos de Minas Gerais; Brasil; Fil: Roques, F.. Laboratoire d; Fil: Widemann, T.. Laboratoire d; Fil: Magalhães, V. S.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Thirouin, A.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; Fil: Duffard, Rene Damian. Centro Informático Científico de Andalucía; España; . Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; Fil: Leiva, R.. Pontificia Universidad Católica de Chile. Department of Electrical Engineering and Center of Astro-Engineering; Chile; Fil: Toledo, I.. Joint Atacama Large Millimeter/submillimeter Array Observatory; Chile; Fil: Capeche, J.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Beisker, W.. International Occultation Timing Association European Section; Alemania; Fil: Pollock, J.. Appalachian State University. Department of Physics and Astronomy; Estados Unidos; Fil: Cedeno Montaña, C. E.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Ivarsen, K. University of North Carolina. Physics and Astronomy Department; Estados Unidos; Fil: Reichart, D.. University of North Carolina. Physics and Astronomy Department; Estados Unidos; Fil: Haislip, J.. University of North Carolina. Physics and Astronomy Department; Estados Unidos; Fil: Lacluyze, A.. University of North Carolina. Physics and Astronomy Department; Estados Unidos

Various studies have shown that there is an empirical relation between the nebular metallicity of a galaxy and its stellar mass. Until now, most studies of the mass-metallicity relation (M–Z) have focused on the abundances of the interstellar medium as measured by emission-line features. This technique thus excludes galaxies with AGN from the working samples, due to the difficulty to measure the nebular abundances when emission-lines are powered both by stars and AGN. With our synthesis code starlight, we are able to recover the stellar metallicities of galaxies from the Sloan Digital Sky Survey (SDSS). Therefore, although we still cannot measure the nebular metallicity in AGN hosts, we know their present-day stellar metallicities. Moreover, because we measure the metallicity of stellar populations of different ages in a galaxy, we are also able also recover the history of its chemical enrichment.

We explore the mass-assembly and chemical enrichment histories of star forming galaxies by applying a population synthesis method to a sample of nearly 70k galaxies culled from over 500k galaxies from the Sloan Digital Sky Survey Data Release 5. Our method decomposes the entire observed spectrum in terms of a sum of simple stellar populations spanning a wide range of ages and metallicities, thus allowing the reconstruction of galaxy histories. A comparative study of galaxy evolution is presented, where galaxies are grouped onto bins of nebular abundances or mass. We find that galaxies whose warm interstellar medium is poor in heavy elements are slow in forming stars. Their stellar metallicities also rise slowly with time, reaching their current values (Z⋆ ~ 1/4Z⊙) in the last ~100 Myr of evolution. Systems with metal rich nebulae, on the other hand, assembled most of their mass and completed their chemical evolution long ago, reaching Z⋆ ~ Z⊙ already at lookback times of a few Gyr. These same trends, which are ultimately a consequence of galaxy downsizing, appear when galaxies are grouped according to their stellar mass. The reconstruction of galaxy histories to this level of detail out of integrated spectra offers promising prospects in the field of galaxy evolution theories.

We revisit the bimodality of the galaxy population seen in the local universe. We address this issue in terms of physical properties of galaxies, such as mean stellar ages and stellar masses, derived from the application of a spectral synthesis method to galaxy spectra from the SDSS. We show that the mean light-weighted stellar age of galaxies presents the best description of the bimodality seen in the galaxy population. The stellar mass has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results give support to the existence of a ‘downsizing’ in galaxy formation, where nowadays massive galaxies tend to have stellar populations older than those found in less massive objects.