Browsing by Author "Vivas, A. K."

Now showing 1 - 8 of 8
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    A DESGW Search for the Electromagnetic Counterpart to the LIGO/Virgo Gravitational-wave Binary Neutron Star Merger Candidate S190510g
    (2020) Garcia, A.; Morgan, R.; Herner, K.; Palmese, A.; Soares Santos, M.; Annis, J.; Brout, D.; Vivas, A. K.; Drlica Wagner, A.; Quirola Vásquez, Jonathan Alexander; Santana Silva, L.; Tucker, D. L.; Allam, S.; Wiesner, M.; Garcia Bellido, J.; Gill, M. S. S.; Sako, M.; Kessler, R.; Davis, T. M.; Scolnic, D.; Casares, J.; Chen, H.; Conselice, C.; Cooke, J.; Doctor, Z.; Foley, R. J.; Horvath, J.; Howell, D. A.; Kilpatrick, C. D.; Lidman, C.; Olivares, E. F.; Paz Chinchon, F.; Pineda G., J.; Rest, A.; Sherman, N.; Abbott, T. M. C.; Aguena, M.; Avila, S.; Bertin, E.; Bhargava, S.; Brooks, D.; Burke, D. L.; Rosell, A. C.; Kind, M. C.; Carretero, J.; Costanzi, M.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.
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    A Segmented Period-Luminosity Relation for Nearby Extragalactic Delta Scuti Stars
    (2022) Martínez-Vázquez, C. E.; Salinas, R.; Vivas, A. K.; Catelan , Marcio
    The period-luminosity relations (PLRs) of Milky Way δ Scuti (δ Sct) stars have been described to the present day by a linear relation. However, when studying extragalactic systems such as the Magellanic Clouds and several dwarf galaxies, we notice for the first time a nonlinear behavior in the PLR of δ Sct stars. Using the largest sample of ~3700 extragalactic δ Sct stars from data available in the literature-mainly based on the Optical Gravitational Lensing Experiment and the Super MAssive Compact Halo Object project in the Large Magellanic Cloud (LMC)-we obtain that the best fit to the period-luminosity (M V ) plane is given by the following piecewise linear relation with a break at logP = -1.03 ± 0.01 (or 0.093 ± 0.002 days) for shorter periods (sp) and longer periods (lp) than the break-point:...
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    Constraints on the Physical Properties of GW190814 through Simulations Based on DECam Follow-up Observations by the Dark Energy Survey
    (2020) Morgan, R.; Soares Santos, M.; Annis, J.; Herner, K.; Garcia, A.; Palmese, A.; Drlica Wagner, A.; Kessler, R.; Garcia Bellido, J.; Quirola Vásquez, Jonathan Alexander; Bachmann, T. G.; Sherman, N.; Allam, S.; Bechtol, K.; Bom, C. R.; Brout, D.; Butler, R. E.; Butner, M.; Cartier, R.; Chen, H.; Conselice, C.; Cook, E.; Davis, T. M.; Doctor, Z.; Farr, B.; Figueiredo, A. L.; Finley, D. A.; Foley, R. J.; Galarza, J. Y.; Gill, M. S. S.; Gruendl, R. A.; Holz, D. E.; Kuropatkin, N.; Lidman, C.; Lin, H.; Malik, U.; Mann, A. W.; Marriner, J.; Marshall, J. L.; Martinez Vazquez, C. E.; Meza, N.; Neilsen, E.; Nicolaou, C.; Olivares, E. F.; Paz Chinchon, F.; Points, S.; Rodriguez, O.; Sako, M.; Scolnic, D.; Smith, M.; Sobreira, F.; Tucker, D. L.; Vivas, A. K.
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    Detailed chemical abundances of distant RR Lyrae stars in the Virgo Stellar Stream
    (2016) Duffau, S.; Sbordone, L.; Vivas, A. K.; Hansen, C. J.; Zoccali, M.; Catelan, Márcio; Minniti, D.; Grebel, E. K.
    We present the first detailed chemical abundances for distant RR Lyrae stars members of the Virgo Stellar Stream (VSS), derived from X- Shooter medium-resolution spectra. Sixteen elements from carbon to barium have been measured in six VSS RR Lyrae stars, sampling all main nucleosynthetic channels. For the first time we will be able to compare in detail the chemical evolution of the VSS progenitor with those of Local Group dwarf spheroidal galaxies (LG dSph) as well as the one of the smooth halo....
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    Mapping the Milky Way Halo Substructures Using RR Lyrae Stars
    (2018) Carballo-Bello, J. A.; Duffau, S.; Vivas, A. K.; Navarrete, C.; Catelan, Márcio
    The Galactic halo is well populated by tidal streams and overdensities, showing its heterogeneus origin and providing important clues about its formation history. RR Lyrae stars have proven to be excellent tracers of halo substructures, due to the quality of the distances that can be derived from them, and the relatively straightforward methods that lead to their clean identification. In this work, we present our observational efforts to unveil and characterize the hypothetical accreted systems in areas of the sky with an evident excess of RR Lyrae stars. In particular, we have focused in the southern hemisphere, where some of these substructures seem to be connected with other northern stellar halo substructures....
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    Near-Field Cosmology with RR Lyrae Variable Stars: a first view of substructure in the southern sky
    (2016) Navarrete, C.; Duffau, S.; Vivas, A. K.; Catelan, Márcio; Hajdu, G.; Torrealba, G.; Cortés, C.; Belokurov, V.; Koposov, S.; Drake, A. J.
    We present the current status of the spectroscopic follow-up of a large number of RR Lyrae (RRL) halo overdensity candidates recently found by Torrealba et al. (2015) using southern-hemisphere data from the Catalina Real-time Transient Survey (CRTS). Characterizing the individual RRL stars in these overdensities is crucial to confirm them as real halo substructures. Low-resolution spectra have been obtained for RRL stars in 11 different overdensities, using the SOAR and Magellan telescopes. Radial velocities and metallicities have been derived so far for 123 and 99 RRL stars, respectively....
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    Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time: A Pioneering Process of Community-focused Experimental Design
    (2022) Bianco, Federica B.; Ivezić, Željko; Jones, R. Lynne; Graham, Melissa L.; Marshall, Phil; Saha, Abhijit; Strauss, Michael A.; Yoachim, Peter; Ribeiro, Tiago; Anguita, Timo; Bauer, A. E.; Bauer, Franz E.; Bellm, Eric C.; Blum, Robert D.; Brandt, William N.; Brough, Sarah; Catelan, Márcio; Clarkson, William I.; Connolly, Andrew J.; Gawiser, Eric; Gizis, John E.; Hložek, Renée; Kaviraj, Sugata; Liu, Charles T.; Lochner, Michelle; Mahabal, Ashish A.; Mandelbaum, Rachel; McGehee, Peregrine; Neilsen, Eric H., Jr.; Olsen, Knut A. G.; Peiris, Hiranya V.; Rhodes, Jason; Richards, Gordon T.; Ridgway, Stephen; Schwamb, Megan E.; Scolnic, Dan; Shemmer, Ohad; Slater, Colin T.; Slosar, Anže; Smartt, Stephen J.; Strader, Jay; Street, Rachel; Trilling, David E.; Verma, Aprajita; Vivas, A. K.; Wechsler, Risa H.; Willman, Beth
    Vera C. Rubin Observatory is a ground-based astronomical facility under construction, a joint project of the National Science Foundation and the U.S. Department of Energy, designed to conduct a multipurpose 10 yr optical survey of the Southern Hemisphere sky: the Legacy Survey of Space and Time. Significant flexibility in survey strategy remains within the constraints imposed by the core science goals of probing dark energy and dark matter, cataloging the solar system, exploring the transient optical sky, and mapping the Milky Way. The survey's massive data throughput will be transformational for many other astrophysics domains and Rubin's data access policy sets the stage for a huge community of potential users. To ensure that the survey science potential is maximized while serving as broad a community as possible, Rubin Observatory has involved the scientific community at large in the process of setting and refining the details of the observing strategy. The motivation, history, and decision-making process of this strategy optimization are detailed in this paper, giving context to the science-driven proposals and recommendations for the survey strategy included in this Focus Issue....
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    The delay of shock breakout due to circumstellar material evident in most type II supernovae
    (2018) Forster, F.; Moriya, T. J.; Maureira, J. C.; Anderson, J. P.; Blinnikov, S.; Bufano, F.; Cabrera Vives, G.; Clocchiatti, Alejandro; De Jaeger, T.; Estevez, P. A.; Galbany, L.; González -Gaitán, S.; Grafener, G.; Hamuy, M.; Hsiao, E. Y.; Huentelemu, P.; Huijse, P.; Kuncarayakti, H.; Martínez, J.; Medina, G.; Olivares, F.; Pignata, Giuliano; Razza, A.; Reyes, I.; San Martín, J.; Smith, R. C.; Vera, E.; Vivas, A. K.; Postigo, A. D.; Yoon, S. C.; Ashall, C.; Fraser, M.; Gal-Yam, A.; Kankare, E.; Le Guillou, L.; Mazzali, P. A.; Walton, N. A.; Young, D. R.