Examinando por Autor "Bono, Giuseppe"
Mostrando 1 - 4 de 4
Resultados por página
Opciones de ordenación
Ítem A DECam view of the diffuse dwarf galaxy Crater II – Variable stars(Oxford University Press, 2020-02) Vivas, A. Katherina; Walker, Alistair R.; Martínez-Vazquez, Clara E.; Monelli, Matteo; Bono, Giuseppe; Dorta, Antonio; Nidever, David L.; Fiorentino, Giuliana; Gallart, Carme; Andreuzzi, Gloria; Braga, Vittorio F.; Dall’Ora, Massimo; Olsen, Knut; Stetson, Peter B.Time series observations of a single dithered field centred on the diffuse dwarf satellite galaxy Crater II were obtained with the Dark Energy Camera (DECam) at the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile, uniformly covering up to two half-light radii. Analysis of the g and i time series results in the identification and characterization of 130 periodic variable stars, including 98 RR Lyrae stars, 7 anomalous Cepheids, and 1 SX Phoenicis star belonging to the Crater II population, and 24 foreground variables of different types. Using the large number of ab-type RR Lyrae stars present in the galaxy, we obtained a distance modulus to Crater II of (m - M)0 = 20.333 ± 0.004 (stat) ± 0.07 (sys). The distribution of the RR Lyrae stars suggests an elliptical shape for Crater II, with an ellipticity of 0.24 and a position angle of 153°. From the RR Lyrae stars, we infer a small metallicity dispersion for the old population of Crater II of only 0.17 dex. There are hints that the most metal-poor stars in that narrow distribution have a wider distribution across the galaxy, while the slightly more metal-rich part of the population is more centrally concentrated. Given the features in the colour-magnitude diagram of Crater II, the anomalous Cepheids in this galaxy must have formed through a binary evolution channel of an old population. © 2019 The Author(s)Ítem Impact of Distance Determinations on Galactic Structure. II. Old Tracers(Springer Netherlands, 2018-08) Kunder, Andrea; Valenti, Elena; Dall’Ora, Massimo; Pietrukowicz, Pawel; Sneden, Chris; Bono, Giuseppe; Braga, Vittorio F.; Ferraro, Iván; Fiorentino, Giuliana; Iannicola, Giacinto; Marconi, Marcella; Martínez-Vázquez, Clara E.; Monelli, Matteo; Musella, Ilaria; Ripepi, Vincenzo; Salaris, Maurizio; Stetson, Peter B.Here we review the efforts of a number of recent results that use old tracers to understand the build up of the Galaxy. Details that lead directly to using these old tracers to measure distances are discussed. We concentrate on the following: (1) the structure and evolution of the Galactic bulge and inner Galaxy constrained from the dynamics of individual stars residing therein; (2) the spatial structure of the old Galactic bulge through photometric observations of RR Lyrae-type stars; (3) the three-dimensional structure, stellar density, mass, chemical composition, and age of the Milky Way bulge as traced by its old stellar populations; (4) an overview of RR Lyrae stars known in the ultra-faint dwarfs and their relation to the Galactic halo; and (5) different approaches for estimating absolute and relative cluster ages. © 2018, Springer Nature B.V.Ítem Rubin Observatory LSST Transients and Variable Stars Roadmap(Institute of Physics, 2023-10) Hambleton, Kelly M.; Bianco, Federica B.; Street, Rachel; Bell, Keaton; Buckley, David; Graham, Melissa; Hernitschek, Nina; Lund, Michael B.; Mason, Elena; Pepper, Joshua; Prša, Andrej; Rabus, Markus; Raiteri, Claudia M.; Szabó, Róbert; Szkody, Paula; Andreoni, Igor; Antoniucci, Simone; Balmaverde, Barbara; Bellm, Eric; Bonito, Rosaria; Bono, Giuseppe; Botticella, Maria Teresa; Brocato, Enzo; Bricman, Katja Bučar; Cappellaro, Enrico; Carnerero, Maria Isabel; Chornock, Ryan; Clarke, Riley; Cowperthwaite, Phil; Cucchiara, Antonino; D’Ammando, Filippo; Dage, Kristen C.; Dall’Ora, Massimo; Davenport, James R.A.; de Martino, Domitilla; de Somma, Giulia; Criscienzo, Marcella Di; Stefano, Rosanne Di; Drout, Maria; Fabrizio, Michele; Fiorentino, Giuliana; Gandhi, Poshak; Garofalo, Alessia; Giannini, Teresa; Gomboc, Andreja; Greggio, Laura; Hartigan, Patrick; Hundertmark, Markus; Johnson, Elizabeth; Johnson, Michael; Jurkic, Tomislav; Khakpash, Somayeh; Leccia, Silvio; Li, Xiaolong; Magurno, Davide; Malanchev, Konstantin; Marconi, Marcella; Margutti, Raffaella; Marinoni, Silvia; Mauron, Nicolas; Molinaro, Roberto; Möller, Anais; Moniez, Marc; Muraveva, Tatiana; Musella, Ilaria; Ngeow, Chow-Choong; Pastorello, Andrea; Petrecca, Vincenzo; Piranomonte, Silvia; Ragosta, Fabio; Reguitti, Andrea; Righi, Chiara; Ripepi, Vincenzo; Rivera Sandoval, Liliana; Stassun, Keivan G.; Stroh, Michael; Terreran, Giacomo; Trimble, Virginia; Tsapras, Yiannis; van Velzen, Sjoert; Venuti, Laura; Vink, Jorick S.The Vera C. Rubin Legacy Survey of Space and Time (LSST) holds the potential to revolutionize time domain astrophysics, reaching completely unexplored areas of the Universe and mapping variability time scales from minutes to a decade. To prepare to maximize the potential of the Rubin LSST data for the exploration of the transient and variable Universe, one of the four pillars of Rubin LSST science, the Transient and Variable Stars Science Collaboration, one of the eight Rubin LSST Science Collaborations, has identified research areas of interest and requirements, and paths to enable them. While our roadmap is ever-evolving, this document represents a snapshot of our plans and preparatory work in the final years and months leading up to the survey’s first light. © 2023 Institute of Physics Publishing. All rights reserved.Ítem The Gaia Parallax Discrepancy for the Cluster Pismis 19 and Separating δ Scutis from Cepheids(Institute of Physics, 2025-04) Majaess, Daniel; Bonatto, Charles J.; Turner, David G.; Saito, Roberto K.; Minniti, Dante; Moni Bidin, Christian; González-Díaz, Danilo; Alonso-Garcia, Javier; Bono, Giuseppe; Braga, Vittorio F.; Navarro, Maria G.; Carraro, Giovanni; Gomez, MatiasPre-Gaia distances for the open cluster Pismis 19 disagree with Gaia parallaxes. A Two Micron All Sky Survey (2MASS) JKs red clump distance was therefore established for Pismis 19 (2.90 ± 0.15 kpc), which reaffirms that zero-point corrections for Gaia are required. OGLE GD-CEP-1864 is confirmed as a member of Pismis 19 on the basis of DR3 proper motions and its 2MASS+Vista Variables in the Vía Láctea color-magnitude position near the tip of the turnoff. That 0.3 day variable star is likely a δ Scuti rather than a classical Cepheid. The case revealed a pertinent criterion to segregate those two populations in tandem with the break in the Wesenheit Leavitt Law (≃0.5 day). Just shortward of that period discontinuity are δ Scutis, whereas beyond the break lie first overtone classical Cepheids mostly observed beyond the first crossing of the instability strip. © 2025. The Author(s). Published by the American Astronomical Society.