Browsing by Author "Cortés, C."
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- ItemAN OVERVIEW OF THE ROTATIONAL BEHAVIOR OF METAL-POOR STARS(2009) Cortés, C.; Catelan, Márcio
- ItemCAPOS: The bulge Cluster APOgee Survey. I. Overview and initial ASPCAP results(2021) Geisler, D.; Villanova, S.; O'Connell, J. E.; Cohen, R. E.; Moni Bidin, C.; Fernández-Trincado, J. G.; Muñoz, C.; Minniti, D.; Zoccali, M.; Rojas-Arriagada, A.; Contreras Ramos, R.; Catelan, Márcio; Mauro, F.; Cortés, C.; Ferreira Lopes, C. E.; Arentsen, A.; Starkenburg, E.; Martin, N. F.; Tang, B.; Parisi, C.; Alonso-García, J.; Gran, F.; Cunha, K.; Smith, V.; Majewski, S. R.; Jönsson, H.; García-Hernández, D. A.; Horta, D.; Mészáros, S.; Monaco, L.; Monachesi, A.; Muñoz, R. R.; Brownstein, J.; Beers, T. C.; Lane, R. R.; Barbuy, B.; Sobeck, J.; Henao, L.; González-Díaz, D.; Miranda, R. E.; Reinarz, Y.; Santander, T. A.Context. Bulge globular clusters (BGCs) are exceptional tracers of the formation and chemodynamical evolution of this oldest Galactic component. However, until now, observational difficulties have prevented us from taking full advantage of these powerful Galactic archeological tools. Aims: CAPOS, the bulge Cluster APOgee Survey, addresses this key topic by observing a large number of BGCs, most of which have only been poorly studied previously. Even their most basic parameters, such as metallicity, [α/Fe], and radial velocity, are generally very uncertain. We aim to obtain accurate mean values for these parameters, as well as abundances for a number of other elements, and explore multiple populations. In this first paper, we describe the CAPOS project and present initial results for seven BGCs. Methods: CAPOS uses the APOGEE-2S spectrograph observing in the H band to penetrate obscuring dust toward the bulge. For this initial paper, we use abundances derived from ASPCAP, the APOGEE pipeline. Results: We derive mean [Fe/H] values of −0.85 ± 0.04 (Terzan 2), −1.40 ± 0.05 (Terzan 4), −1.20 ± 0.10 (HP 1), −1.40 ± 0.07 (Terzan 9), −1.07 ± 0.09 (Djorg 2), −1.06 ± 0.06 (NGC 6540), and −1.11 ± 0.04 (NGC 6642) from three to ten stars per cluster. We determine mean abundances for eleven other elements plus the mean [α/Fe] and radial velocity. CAPOS clusters significantly increase the sample of well-studied Main Bulge globular clusters (GCs) and also extend them to lower metallicity. We reinforce the finding that Main Bulge and Main Disk GCs, formed in situ, have [Si/Fe] abundances slightly higher than their accreted counterparts at the same metallicity. We investigate multiple populations and find our clusters generally follow the light-element (anti)correlation trends of previous studies of GCs of similar metallicity. We finally explore the abundances of the iron-peak elements Mn and Ni and compare their trends with field populations. Conclusions: CAPOS is proving to be an unprecedented resource for greatly improving our knowledge of the formation and evolution of BGCs and the bulge itself....
- ItemDisentangling multiple stellar populations in globular clusters using the Strömgren system(2015) Alonso-García, J.; Catelan, Márcio; Amigo, P.; Cortés, C.; Kuehn, C. A.; Grundahl, F.; López, G.; Salinas, R.; Smith, H. A.; Stetson, P. B.; Sweigart, Allen V.; Valcarce, Aldo A. R.; Zoccali, M.An increasing amount of spectroscopic and photometric evidence is showing that the stellar populations of globular clusters are not as simple as they have been considered for many years. The presence of at least two different populations of stars is being discovered in a growing number of globular clusters, both in our Galaxy and in others. We have started a series of observations of Galactic globular clusters using the Strömgren photometric system in order to find the signatures of these multiple populations and establish their presence in a more complete sample of globular clusters in the Milky Way, and to study their radial distributions and extensions. We present here the first results of our survey....
- ItemEffect of soiling and sunlight exposure on the performance ratio of photovoltaic technologies in Santiago, Chile(2016) Urrejola, E.; Antonanzas, J.; Ayala, P.; Salgado, M.; Ramírez, G.; Cortés, C.; Pino, A.; Escobar Moragas, Rodrigo
- ItemErratum: "The Globular Cluster NGC 5286. II. Variable Stars" (2010, AJ, 139, 357)(2010) Zorotovic, M.; Catelan, Márcio; Smith, H. A.; Pritzl, B. J.; Aguirre, P.; Angulo, R. E.; Aravena, M.; Assef, R. J.; Contreras, C.; Cortés, C.; De Martini, G.; Escobar, M. E.; González, D.; Jofré, P.; Lacerna, I.; Navarro, C.; Palma, O.; Prieto, G. E.; Recabarren, E.; Triviño, J.; Vidal, E.The Fourier decomposition program used in our paper contained a small error that affected the calculation of the temperatures as well as the V - I colors inferred for the RRab stars. The temperatures that appear in Table 6 in the published article are slightly overestimated, and the V - I colors underestimated. A corrected version of Table 6 is presented below....
- ItemK2-161b : a low-density super-Neptune on an eccentric orbit.(2018) Brahm Scott, Rafael; Espinoza, N.; Rabus, Markus; Jordán Colzani, Andrés Cristóbal; Lachaume, Regis; Rojas Aracena, Felipe Alberto.; Zapata Sapiencia, Alvaro Mauricio.; Cortés, C.; Drass, Holger; Díaz, M.R.; Vučković, M.
- ItemMultiple populations in Galactic globular clusters from a Strömgren perspective(2014) Alonso-García, J.; Catelan, Márcio; Amigo, P.; Cortés, C.; Kuehn, C. A.; Grundahl, F.; López, G.; Salinas, R.; Smith, H. A.; Stetson, P. B.; Sweigart, Allen V.; Valcarce, Aldo A. R.; Zoccali, M.Our view of the stellar populations in globular clusters has radically changed in the last years. Now we are coming to believe that all globular clusters host at least two distinct stellar populations. We present in this contribution preliminary results of a photometric survey we are currently conducting to disentangle photometrically the several populations in a significant number of Galactic globular clusters, using the Strömgren system, aiming to characterize their relative ratios and their radial distributions....
- ItemMultiple populations in Galactic globular clusters: a survey in the Strömgren system(2013) Alonso-García, J.; Catelan, Márcio; Amigo, P.; Cortés, C.; Kuehn, C. A.; Grundahl, F.; López, G.; Salinas, R.; Smith, H. A.; Stetson, P. B.; Sweigart, Allen V.; Valcarce, Aldo A. R.; Zoccali, M.We are coming to believe that stellar populations in globular clusters are not as simple as they were once thought to be. A growing amount of photometric and spectroscopic evidence shows that globular clusters host at least two different stellar populations. In our contribution to these proceedings we present the first results of a survey we are conducting to look for the presence of multiple populations in a significant number of Galactic globular clusters, using the Strömgren system. We intend to photometrically separate these populations and characterize their radial distributions and extensions....
- ItemNear-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....
- ItemNGC 5694: another extra-galactic globular cluster(2013) Mucciarelli, A.; Bellazzini, M.; Catelan, Márcio; Amigo, P.; Correnti, M.; Cortés, C.; Dalessandro, E.; D'Orazi, V.We discuss the chemical composition of six giant stars of the outer Halo globular cluster NGC 5694, through the analysis of UVES@FLAMES high-resolution spectra. The cluster has an average iron content [Fe/H]=-1.83±0.01, solar-scaled [alpha /Fe] ratios and a very low Ba abundance ([Ba/Fe]=-0.71±0.06). These anomalous abundance patterns are different from those observed in other Halo globular clusters but similar to those of the metal-poor stars in typical dwarf spheroidal galaxies. These findings suggest an extra-galactic origin for NGC 5694, likely from a dwarf spheroidal galaxy....
- ItemRespiratory syncytial virus detection in cells and clinical samples by using three new monoclonal antibodies(2014) Gomez, Ricardo; Mora, J.; Cortés, C.; Riedel, C.; Ferrés Garrido, Marcela Viviana; Bueno Ramírez, Susan; Kalergis Parra, Alexis Mikes
- ItemSolar energy resource assessment in Chile: Satellite estimation and ground station measurements(2014) Escobar Moragas, Rodrigo; Cortés, C.; Pino, A.; Pereira, E.; Martins, F.; Cardemil Iglesias, José Miguel
- ItemStellar parameters for stars of the CoRoT exoplanet field(2015) Cortés, C.; Maciel, S. C.; Vieira, S.; Ferreira Lopes, C. E.; Leão, I. C.; De Oliveira, G. P.; Correia, C.; Canto Martins, B. L.; Catelan, Márcio; De Medeiros, J. R.
- ItemThe RR Lyrae Period-Luminosity-(Pseudo)Color and Period-Color-(Pseudo)Color Relations in the Strömgren Photometric System: Theoretical Calibration(2008) Cortés, C.; Catelan, MarcioWe present a theoretical calibration of the RR Lyrae period-luminosity-color and period-color-color relations in the multiband uvby Strömgren photometric system. Our theoretical work is based on calculations of synthetic horizontal branches (HBs) for four different metallicities, fully taking into account evolutionary effects for a wide range in metallicities and HB morphologies. While our results show that "pure" period-luminosity and period-color relations do not exist in the Strömgren system, which is due to the large scatter that is brought about by evolutionary effects when the uvby bandpasses are used, they also reveal that such scatter can be almost completely taken into account by incorporating Strömgren pseudocolor [C0 ≡ (u - v)0 - (v - b)0] terms into those equations, thus leading to tight period-luminosity-pseudocolor (PLpsC) and period-color-pseudocolor (PCpsC) relations. We provide the latter in the form of analytical fits, so that they can be applied with high precision even in the case of field stars. In view of the very small sensitivity of C0 to interstellar reddening, our PLpsC and PCpsC relations should be especially useful for the derivation of high-precision distance and reddening values. In this sense, we carry out a first application of our relations to field RR Lyrae stars, finding evidence that the stars RR Lyr, SU Dra, and SS Leo, but not SV Hya, are somewhat overluminous (by amounts ranging from simeq0.05 to 0.20 mag in y, and thus V) with respect to the average for other RR Lyrae stars of similar metallicity....