Browsing by Author "Gonzalez, Oscar A."

Now showing 1 - 7 of 7
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    Characterization of the VVV Survey RR Lyrae Population across the Southern Galactic Plane
    (2017) Minniti, D.; Dekany, Istvan; Majaess, Daniel; Palma, Tali; Pullen, Joyce; Rejkuba, Marina; Alonso-García, Javier; Catelan, Márcio; Hempel, Maren; Zoccali, Manuela; Contreras Ramos, Rodrigo Andrés; Gonzalez, Oscar A.; Irwin, Mike; Lucas, Philip W.; Saito, Roberto K.; Tissera, Patricia; Valenti, Elena
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    Extinction Ratios in the Inner Galaxy as Revealed by the VVV Survey
    (2017) Alonso-García Javier; Minniti, D.; Catelan, Márcio; Contreras Ramos, Rodrigo Andrés; Gonzalez, Oscar A.; Hempel, Maren; Lucas Philip W.; Saito Roberto K.; Valenti Elena; Zoccali, Manuela
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    Milky Way demographics with the VVV survey IV. PSF photometry from almost one billion stars in the Galactic bulge and adjacent southern disk
    (2018) Alonso-Garcia, Javier; Saito, Roberto K.; Hempel, Maren; Minniti, D.; Pullen, Joyce; Catelan, Márcio; Contreras Ramos, Rodrigo Andrés; Cross, Nicholas J.G.; Gonzalez, Oscar A.; Zoccali, Manuela; Lucas, Philip W.; Palma, Tali; Valenti, Elena
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    MOONS - Multi Object spectroscopy for the VLT: overview and instrument integration update
    (2022) Gonzalez, Oscar A.; Cirasuolo, Michele; Taylor, William; Black, Martin; Rees, Phil; Bryson, Ian; Chittick, Stephen; Afonso, Jose; Lilly, Simon; Flores, Hector; Maiolino, Roberto; Oliva, Ernesto; Paltani, Stephane; Vanzi, Leonardo; Abreu, Manuel; Amans, Jean-Philippe; Atkinson, David; Beard, Steven; Belfiore, Andrea; Breen, Ciaran; Bayo, Amelia; Born, Andy; Cabral, Alexandre; Chapman, Lee; Cochrane, William; Coelho, Joao; Colling, Miriam; Conzelmann, Ralf; Dalessio, Francesco; Davidson, George; Delplancke-Stroebele, Francoise; Fisher, Martin; Forchi, Vincenzo; Franzetti, Paolo; Garilli, Bianca; Gargiulo, Adriana; Guinouard, Isabelle; Gutierrez, Pablo; Haigron, Regis; Hammersley, Peter; Ivanov, Valentin; Ives, Derek; Iwert, Olaf; King, David; Kovacz, Suzanne; Laporte, Philippe; Lee, David; Li Causi, Gianluca; Macleod, Alastair; Alvarez, Domingo; Oliveira, Antonio; Palsa, Ralf; Parra, Manuel; Pedichini, Fernando; Pena, Vicente; Petr-Gotzens, Monika; Rodrigues, Myriam; Royer, Frederic; Santo, Pedro; Sepulveda, Jorge; Sharman, Robyn; Shen, Tzu-Chiang; Sordet, Michael; Strachan, Jonathan; Tait, Graham; Tejeda, Alexis; Tozzi, Andrea; O'Malley, Norman; Waring, Chris; Watson, Stephen; Willemse, Bart; Gao Xiaofeng; Yang, Yanbin; Zoccali, Manuela
    The Multi Object Optical and Near-infrared Spectrograph (MOONS) instrument is the next generation multi-object spectrograph for the Very Large Telescope (VLT). The instrument combines the high multiplexing capability offered by 1000 optical fibres deployed by individual robotic positioners with a novel spectrograph able to provide both low- and high-resolution spectroscopy simultaneously across the wavelength range 0.64 mu m - 1.8 mu m. Powered by the collecting area of the 8-m VLT, MOONS will provide the astronomical community with a world-leading facility able to serve a wide range of Galactic, Extragalactic and Cosmological studies. This paper provides an updated overview of the instrument and its construction progress, reporting on the ongoing integration phase.
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    Separation of stellar populations by an evolving bar: implications for the bulge of the Milky Way
    (2017) Debattista, Victor P.; Ness, Melissa; Gonzalez, Oscar A.; Freeman, K.; Zoccali, Manuela; Minniti, D.
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    The Imprint of Clump Formation at High Redshift. II. The Chemistry of the Bulge
    (2023) Debattista, Victor P.; Liddicott, David J.; Gonzalez, Oscar A.; Beraldo e Silva, Leandro; Amarante, Joao A. S.; Lazar, Ilin; Zoccali, Manuela; Valenti, Elena; Fisher, Deanne B.; Khachaturyants, Tigran; Nidever, David L.; Quinn, Thomas R.; Du, Min; Kassin, Susan
    In Paper I, we showed that clumps in high-redshift galaxies, having a high star formation rate density (sigma(SFR)), produce disks with two tracks in the [Fe/H]-[alpha/Fe] chemical space, similar to that of the Milky Way's (MW's) thin+thick disks. Here we investigate the effect of clumps on the bulge's chemistry. The chemistry of the MW's bulge is comprised of a single track with two density peaks separated by a trough. We show that the bulge chemistry of an N-body + smoothed particle hydrodynamics clumpy simulation also has a single track. Star formation within the bulge is itself in the high-sigma(SFR) clumpy mode, which ensures that the bulge's chemical track follows that of the thick disk at low [Fe/H] and then extends to high [Fe/H], where it peaks. The peak at low metallicity instead is comprised of a mixture of in situ stars and stars accreted via clumps. As a result, the trough between the peaks occurs at the end of the thick disk track. We find that the high-metallicity peak dominates near the mid-plane and declines in relative importance with height, as in the MW. The bulge is already rapidly rotating by the end of the clump epoch, with higher rotation at low [alpha/Fe]. Thus clumpy star formation is able to simultaneously explain the chemodynamic trends of the MW's bulge, thin+thick disks, and the splash.
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    The structure behind the galactic bar traced by red clump stars in the VVV survey
    (2018) Gonzalez, Oscar A.; Minniti, D.; Valenti, Elena; Alonso-Garcia, Javier; Debattista, Victor P.; Zoccali, Manuela; Rejkuba, Marina; Dias, Bruno; Surot, Bruno; Hempel, Maren