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1. The R-process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510

Author

Placco, VM, Santucci, RM, Yuan, Z, Mardini, MK, Holmbeck, EM, Wang, X, Surman, R, Hansen, TT, Roederer, IU, Beers, TC, Choplin, A, Ji, AP, Ezzeddine, R, Frebel, A, Sakari, CM, Whitten, DD, Zepeda, J, Placco, VM, Santucci, RM, Yuan, Z, Mardini, MK, Holmbeck, EM, Wang, X, Surman, R, Hansen, TT, Roederer, IU, Beers, TC, Choplin, A, Ji, AP, Ezzeddine, R, Frebel, A, Sakari, CM, Whitten, DD, and Zepeda, J

Abstract

© 2020. The American Astronomical Society. All rights reserved. We report on the spectroscopic analysis of RAVE J183013.5-455510, an extremely metal-poor star, highly enhanced in CNO, and with discernible contributions from the rapid neutron-capture process. There is no evidence of binarity for this object. At =-3.57, this star has one of the lowest metallicities currently observed, with 18 measured abundances of neutron-capture elements. The presence of Ba, La, and Ce abundances above the solar system r-process predictions suggests that there must have been a non-standard source of r-process elements operating at such low metallicities. One plausible explanation is that this enhancement originates from material ejected at unusually high velocities in a neutron star merger event. We also explore the possibility that the neutron-capture elements were produced during the evolution and explosion of a rotating massive star. In addition, based on comparisons with yields from zero-metallicity faint supernova, we speculate that RAVE J1830-4555 was formed from a gas cloud pre-enriched by both progenitor types. From analysis based on Gaia DR2 measurements, we show that this star has orbital properties similar to the Galactic metal-weak thick-disk stellar population.

Published
2021

2. The R-Process Alliance: Fourth Data Release from the Search for R-process-enhanced Stars in the Galactic Halo

Author

Holmbeck, EM, Hansen, TT, Beers, TC, Placco, VM, Whitten, DD, Rasmussen, KC, Roederer, IU, Ezzeddine, R, Sakari, CM, Frebel, A, Drout, MR, Simon, JD, Thompson, IB, Bland-Hawthorn, J, Gibson, BK, Grebel, EK, Kordopatis, G, Kunder, A, Meléndez, J, Navarro, JF, Reid, WA, Seabroke, G, Steinmetz, M, Watson, F, Wyse, RFĠ, Holmbeck, EM, Hansen, TT, Beers, TC, Placco, VM, Whitten, DD, Rasmussen, KC, Roederer, IU, Ezzeddine, R, Sakari, CM, Frebel, A, Drout, MR, Simon, JD, Thompson, IB, Bland-Hawthorn, J, Gibson, BK, Grebel, EK, Kordopatis, G, Kunder, A, Meléndez, J, Navarro, JF, Reid, WA, Seabroke, G, Steinmetz, M, Watson, F, and Wyse, RFĠ

Abstract

© 2020. The American Astronomical Society. All rights reserved. This compilation is the fourth data release from the R-Process Alliance (RPA) search for r-process-enhanced stars and the second release based on "snapshot"high-resolution (R ∼ 30,000) spectra collected with the du Pont 2.5 m Telescope. In this data release, we propose a new delineation between the r-I and r-II stellar classes at, instead of the empirically chosen level previously in use, based on statistical tests of the complete set of RPA data released to date. We also statistically justify the minimum level of [Eu/Fe] for definition of the r-I stars, [Eu/Fe] > +0.3. Redefining the separation between r-I and r-II stars will aid in the analysis of the possible progenitors of these two classes of stars and determine whether these signatures arise from separate astrophysical sources at all. Applying this redefinition to previous RPA data, the number of identified r-II and r-I stars changes to 51 and 121, respectively, from the initial set of data releases published thus far. In this data release, we identify 21 new r-II, 111 new r-I (plus 3 re-identified), and 7 new (plus 1 re-identified) limited-r stars out of a total of 232 target stars, resulting in a total sample of 72 new r-II stars, 232 new r-I stars, and 42 new limited-r stars identified by the RPA to date.

Published
2021

3. The Southern Photometric Local Universe Survey (S-PLUS): improved SEDs, morphologies, and redshifts with 12 optical filters

Author

Universidad de La Serena (Chile), Centro de Estudios de Física del Cosmos de Aragón, Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Financiadora de Estudos e Projetos (Brasil), National Science Foundation (US), Southern Office of Aerospace Research and Development (US), Consejo Superior de Investigaciones Científicas (España), Ministerio de Economía y Competitividad (España), European Commission, Universidad Nacional Autónoma de México, Alfred P. Sloan Foundation, National Aeronautics and Space Administration (US), Ministry of Education, Culture, Sports, Science and Technology (Japan), Max Planck Society, Higher Education Funding Council for England, American Museum of Natural History, Leibniz Institute for Astrophysics Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University (US), Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements (US), Kavli Institute for Particle Astrophysics and Cosmology, Chinese Academy of Sciences, Los Alamos National Laboratory, Max Planck Institute for Astronomy, Max Planck Institute for Astrophysics, New Mexico State University, The Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, U.S. Naval Observatory, University of Washington, Fermilab, Institute for Advanced Study (Germany), Johns Hopkins University, de Oliveira, C. M., Ribeiro, T., Schoenell, W., Kanaan, A., Overzier, R. A., Molino, A., Sampedro, L., Coelho, P., Barbosa, Carlos Eduardo, Cortesi, A., Costa-Duarte, M. V., Brito-Silva, D., Daflon, S., Buzzo, M. L., Farias, H., Hernandez-Fernandez, J. D., Kann, D.A., Damke, G., De Paula, D. F., Dors, O. L., Escudero, C. G., Montero-Dorta, A. D., Fernandes, C., Nemmen, R. S., Katena, L., Oliveira, A. S., Arancibia, M. J., Pattaro, E., Labayru, C., Quint, B., Jatenco-Pereira, V., Rodrigues, I., Riguccini, L., Lazzaro, D., Saha, K., Roig-Roig, Ferran, Neto, G. B. L., Sesto, L. A., Santos, R., Lopes, A. R., Teixeira, R., Silva, R., Magalhães, Regina, Munoz-Elgueta, N., Trevisan, M., de Souza, R. C. T., Makler, M., Castellon, J. L. Nilo, Vika, M., Urrutia-Viscarra, F., de Menezes, R., Ortiz, D., Herpich, F.R., Werle, A., Telles, E., Miralda-Escudé, Jordi, Pereira, C. B., Monteiro-Oliveira, R., Placco, V. M., Ugarte Postigo, Antonio de, Vitorelli, A. Z., Hernández-Jiménez, J.A., Pinto, H. J. R., Rossi, S., Muller, A. S., Castelli, A. V. S., Beers, T. C., Thöne, Cristina Carina, Bonoli, Silvia, Veiga, C. H., Vinicius-Lima, E., Werner, S. V., de Souza, G. F., Xavier, H. S., Gonzalez, A. H., Zaritsky, D., Jaffe, Y., Gutiérrez-Soto, L. A., Abramo, L. R., Lopes, PAA, Kerber, L. O., Saito, R. K., Novais, P. M., Menéndez-Delmestre, Karín, Chies-Santos, A.L., Queiroz, C., Pereira, E. S., Ederoclite, Alessandro, Bonatto, C., Santucci, R. M., Santos, W. A., de Oliveira, R. L., Cypriano, E. S., Westera, P., Siffert, B. B., Gonçalves, D. R., de Souza, RS, Akras, S., Alcaniz, Jailson S., Reis, R. R. R., Almeida, L. A., Ferrari, F., Almeida-Fernandes, F., Ortega-Minakata, R. A., Barbosa, C. L., Whitten, DD, Gonçalves, T. S., Hartmann, EA, Lima-Dias, C., Nakazono, L. M. I., Perottoni, H. D., Caffer, J., Santos-Silva, T., Cano, Z., Sodre, L., Castejon, M., Alonso-Garcia, J., Dantas, M. L. L., Torres-Flores, S., de la Reza, R., Alencar, S., Diem, K. G., de Azevedo, L. J. D., Alvarez-Candal, A., Dupke, Renato A., Donnerstein, R., Amram, P., Faifer, F. R., Eikenberry, S., Azanha, L., Fontes, S., Fernandes, B., Barbá, R. H., Campillay, A., Gregorio-Hetem, J., Hirata, N. S. T., Bernardinelli, P. H., Carvano, J.M., Jiménez-Teja, Y., Izzo, L., Fernandes, M. B., Fernandes, R. C., Branco, V., Krabbe, A. C., Galarza, A., Universidad de La Serena (Chile), Centro de Estudios de Física del Cosmos de Aragón, Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Financiadora de Estudos e Projetos (Brasil), National Science Foundation (US), Southern Office of Aerospace Research and Development (US), Consejo Superior de Investigaciones Científicas (España), Ministerio de Economía y Competitividad (España), European Commission, Universidad Nacional Autónoma de México, Alfred P. Sloan Foundation, National Aeronautics and Space Administration (US), Ministry of Education, Culture, Sports, Science and Technology (Japan), Max Planck Society, Higher Education Funding Council for England, American Museum of Natural History, Leibniz Institute for Astrophysics Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University (US), Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements (US), Kavli Institute for Particle Astrophysics and Cosmology, Chinese Academy of Sciences, Los Alamos National Laboratory, Max Planck Institute for Astronomy, Max Planck Institute for Astrophysics, New Mexico State University, The Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, U.S. Naval Observatory, University of Washington, Fermilab, Institute for Advanced Study (Germany), Johns Hopkins University, de Oliveira, C. M., Ribeiro, T., Schoenell, W., Kanaan, A., Overzier, R. A., Molino, A., Sampedro, L., Coelho, P., Barbosa, Carlos Eduardo, Cortesi, A., Costa-Duarte, M. V., Brito-Silva, D., Daflon, S., Buzzo, M. L., Farias, H., Hernandez-Fernandez, J. D., Kann, D.A., Damke, G., De Paula, D. F., Dors, O. L., Escudero, C. G., Montero-Dorta, A. D., Fernandes, C., Nemmen, R. S., Katena, L., Oliveira, A. S., Arancibia, M. J., Pattaro, E., Labayru, C., Quint, B., Jatenco-Pereira, V., Rodrigues, I., Riguccini, L., Lazzaro, D., Saha, K., Roig-Roig, Ferran, Neto, G. B. L., Sesto, L. A., Santos, R., Lopes, A. R., Teixeira, R., Silva, R., Magalhães, Regina, Munoz-Elgueta, N., Trevisan, M., de Souza, R. C. T., Makler, M., Castellon, J. L. Nilo, Vika, M., Urrutia-Viscarra, F., de Menezes, R., Ortiz, D., Herpich, F.R., Werle, A., Telles, E., Miralda-Escudé, Jordi, Pereira, C. B., Monteiro-Oliveira, R., Placco, V. M., Ugarte Postigo, Antonio de, Vitorelli, A. Z., Hernández-Jiménez, J.A., Pinto, H. J. R., Rossi, S., Muller, A. S., Castelli, A. V. S., Beers, T. C., Thöne, Cristina Carina, Bonoli, Silvia, Veiga, C. H., Vinicius-Lima, E., Werner, S. V., de Souza, G. F., Xavier, H. S., Gonzalez, A. H., Zaritsky, D., Jaffe, Y., Gutiérrez-Soto, L. A., Abramo, L. R., Lopes, PAA, Kerber, L. O., Saito, R. K., Novais, P. M., Menéndez-Delmestre, Karín, Chies-Santos, A.L., Queiroz, C., Pereira, E. S., Ederoclite, Alessandro, Bonatto, C., Santucci, R. M., Santos, W. A., de Oliveira, R. L., Cypriano, E. S., Westera, P., Siffert, B. B., Gonçalves, D. R., de Souza, RS, Akras, S., Alcaniz, Jailson S., Reis, R. R. R., Almeida, L. A., Ferrari, F., Almeida-Fernandes, F., Ortega-Minakata, R. A., Barbosa, C. L., Whitten, DD, Gonçalves, T. S., Hartmann, EA, Lima-Dias, C., Nakazono, L. M. I., Perottoni, H. D., Caffer, J., Santos-Silva, T., Cano, Z., Sodre, L., Castejon, M., Alonso-Garcia, J., Dantas, M. L. L., Torres-Flores, S., de la Reza, R., Alencar, S., Diem, K. G., de Azevedo, L. J. D., Alvarez-Candal, A., Dupke, Renato A., Donnerstein, R., Amram, P., Faifer, F. R., Eikenberry, S., Azanha, L., Fontes, S., Fernandes, B., Barbá, R. H., Campillay, A., Gregorio-Hetem, J., Hirata, N. S. T., Bernardinelli, P. H., Carvano, J.M., Jiménez-Teja, Y., Izzo, L., Fernandes, M. B., Fernandes, R. C., Branco, V., Krabbe, A. C., and Galarza, A.

Abstract

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

Published
2019

4. Light curves of the neutron star merger GW170817/SSS17a: Implications for r-process nucleosynthesis.

Author

Drout MR, Piro AL, Shappee BJ, Kilpatrick CD, Simon JD, Contreras C, Coulter DA, Foley RJ, Siebert MR, Morrell N, Boutsia K, Di Mille F, Holoien TW, Kasen D, Kollmeier JA, Madore BF, Monson AJ, Murguia-Berthier A, Pan YC, Prochaska JX, Ramirez-Ruiz E, Rest A, Adams C, Alatalo K, Bañados E, Baughman J, Beers TC, Bernstein RA, Bitsakis T, Campillay A, Hansen TT, Higgs CR, Ji AP, Maravelias G, Marshall JL, Bidin CM, Prieto JL, Rasmussen KC, Rojas-Bravo C, Strom AL, Ulloa N, Vargas-González J, Wan Z, and Whitten DD

Abstract

On 17 August 2017, gravitational waves (GWs) were detected from a binary neutron star merger, GW170817, along with a coincident short gamma-ray burst, GRB 170817A. An optical transient source, Swope Supernova Survey 17a (SSS17a), was subsequently identified as the counterpart of this event. We present ultraviolet, optical, and infrared light curves of SSS17a extending from 10.9 hours to 18 days postmerger. We constrain the radioactively powered transient resulting from the ejection of neutron-rich material. The fast rise of the light curves, subsequent decay, and rapid color evolution are consistent with multiple ejecta components of differing lanthanide abundance. The late-time light curve indicates that SSS17a produced at least ~0.05 solar masses of heavy elements, demonstrating that neutron star mergers play a role in rapid neutron capture (r-process) nucleosynthesis in the universe., (Copyright © 2017, American Association for the Advancement of Science.)

Published
2017
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