CCD Washington photometry of four poorly studied open clusters in the two inner quadrants of the galactic plane

Complementing our Washington photometric studies on Galactic open clusters (OCs), we now focus on four poorly studied OCs located in the first and fourth Galactic quadrants, namely BH 84, NGC 5381, BH 211 and Czernik 37. We have obtained CCD photometry in the Washington system $C$ and $T_1$ passbands down to $T_1$ $\sim$ 18.5 magnitudes for these four clusters. Their positions and sizes were determined using the stellar density radial profiles. We derived reddening, distance, age and metallicity of the clusters from extracted $(C-T_1,T_1)$ color-magnitude diagrams (CMDs), using theoretical isochrones computed for the Washington system. There are no previous photometric data in the optical band for BH 84, NGC 5381 and BH 211. The CMDs of the observed clusters show relatively well defined main sequences, except for Czernik 37, wherein significant differential reddening seems to be present. The red giant clump is clearly seen only in BH 211. For this cluster, we estimated the age in (1000$^{+260}_{-200}$) Myr, assuming a metallicity of $Z$ = 0.019. BH 84 was found to be much older than it was previously believed, while NGC 5381 happened to be much younger than previously reported. The heliocentric distances to these clusters are found to range between 1.4 and 3.4 kpc. BH 84 appears to be located at the solar galactocentric distance, while NGC 5381, BH 211 and Czernik 37 are situated inside the solar ring.Comment: 30 pages, 9 figures, 10 table

Ca II Triplet Spectroscopy of Small Magellanic Cloud Red Giants. III. Abundances and Velocities for a Sample of 14 Clusters

We obtained spectra of red giants in 15 Small Magellanic Cloud (SMC) clusters in the region of the CaII lines with FORS2 on the Very Large Telescope (VLT). We determined the mean metallicity and radial velocity with mean errors of 0.05 dex and 2.6 km/s, respectively, from a mean of 6.5 members per cluster. One cluster (B113) was too young for a reliable metallicity determination and was excluded from the sample. We combined the sample studied here with 15 clusters previously studied by us using the same technique, and with 7 clusters whose metallicities determined by other authors are on a scale similar to ours. This compilation of 36 clusters is the largest SMC cluster sample currently available with accurate and homogeneously determined metallicities. We found a high probability that the metallicity distribution is bimodal, with potential peaks at -1.1 and -0.8 dex. Our data show no strong evidence of a metallicity gradient in the SMC clusters, somewhat at odds with recent evidence from CaT spectra of a large sample of field stars Dobbie et al. (2014). This may be revealing possible differences in the chemical history of clusters and field stars. Our clusters show a significant dispersion of metallicities, whatever age is considered, which could be reflecting the lack of a unique AMR in this galaxy. None of the chemical evolution models currently available in the literature satisfactorily represents the global chemical enrichment processes of SMC clusters.Comment: 49 pages, 15 figures. Accepted for publication in A

Determinación de parámetros fundamentales de dos cúmulos abiertos del cuarto cuadrante galáctico en base a fotometría de Washington

We present preliminary results obtained from a photometric analysis in the Washington system C and T1 passbands of two poorly known open clusters (OCs) located in the fourth Galactic quadrant: BH 84 and BH 211. Based on the best fits of theoretical isochrones to the (T1, C −T1) colour- magnitude diagrams, we derive the fundamental cluster parameters. The present results are part of a major project which aims to characterize almost a hundred OCs observed and analyzed in a homogeneous way.Presentamos resultados preliminares obtenidos a partir del análisis fotométrico en las bandas C y T1 del Sistema de Washington de 2 cúmulos abiertos (CAs) pobremente estudiados del cuarto cuadrante galáctico: BH 84 y BH 211. En base a los mejores ajustes de isócronas teóricas a los diagramas color-magnitud (T1, C −T1), derivamos los parámetros fundamentales de ambos objetos. Los presentes resultados constituyen parte de un proyecto mayor que prevé la caracterización de casi un centenar de CAs observados y analizados de manera homogénea.Fil: Marcionni, N.. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Parisi, M. C.. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Palma, Tali. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Fotometría de Washington de cúmulos abiertos proyectados en dirección hacia el centro de la Galaxia

Resumen. Presentamos resultados preliminares obtenidos a partir del análisis fotométrico en las bandas C y T1 del sistema fotométrico de Washington de cuatro cúmulos abiertos (CAs) pobremente estudiados proyectados en la dirección del centro galáctico: Dias 6, NGC 5381, Ruprecht 128 y Czernik 37. A partir de los diagramas color-magnitud (C − T1, T1) y mediante el ajuste de isócronas teóricas calculadas para el sistema de Washington, derivamos sus parámetros fundamentales. Los presentes resultados constituyen parte de un proyecto mayor que prevé la caracterización de un centenar de CAs observados y analizados de manera homogénea.Abstract. We present preliminary results obtained from the photometric analysis in the C and T1 bands of the Washington photometric system of four poorly studied open clusters (OCs): Dias 6, NGC 5381, Ruprecht 128 and Czernik 37, projected in the Galactic center direction. We derived their fundamental parameters from their (C − T1, T1) colormagnitude diagrams, using theoretical isochrones computed for the Washington system. The present results are part of a major project which aims at characterizing almost a hundred OCs observed and analyzed in a homogeneous way.publishedVersionFil: Clariá Olmedo, Juan José. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Clariá Olmedi, Juan José. Conicet, Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Argentina.Fil: Parisi, María Celeste. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Parisi, María Celeste. Conicet, Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Argentina.Fil: Palma, Tali. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Palma, Tali. Conicet, Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Argentina.Fil: Oddone, Mónica Alejandra. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Ahumada, Andrea Verónica. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Ahumada, Andrea Verónica. Conicet, Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Argentina.Astronomía (incluye Astrofísica y Ciencias del Espacio

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Determination of fundamental astrophysical properties of poorly known galactic open clusters from Washington photometry

Abstract: As a complement to our photometric studies on southern open clusters (OCs), we present preliminary results obtained from a photometric analysis in the Washington system C and T1 passbands of some poorly known Galactic OCs. The observations were made using the CTIO 0.9 m telescope. Basically, we determine reddening, distance, and age of the observed objects. The present results are part of a major project which aims to characterize almost a hundred OCs observed and analyzed in a homogeneous way.Fil: Parisi, María Celeste. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Parisi, María Celeste. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Clariá Olmedo, Juan José. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Ahumada, Andrea Verónica. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Otras Ciencias Naturales y Exacta

CaTaclysm in the SMC - star clusters vs. field stars

We present new results based on VLT Ca Triplet (CaT) medium resolution spectroscopy of some 200 red giantmembers of 29 SMC intermediate - old age clusters. We derive mean cluster velocities to a few km/s and mean metallicities to 0.05 dex. We also derive accurate velocities and metallicities for about 750 surrounding field giants. We investigate the metallicity distribution, age-metallicity relation and metallicity gradient in great detail for the SMC using this large and homogeneous database. We find a number of interesting results and some surprising differences between the clusters and fields. The clusters display a likely bimodal metallicity distribution while the field stars are unimodal. The clusters show no strong evidence of a metallicity gradient while the field stars show a strong negative gradient in the inner region of the galaxy that appears to reverse sign in the outer region. The difference between the cluster metallicity and the mean of the surrounding field stars is a strong function of the cluster metallicity. The age-metallicity relation of the clusters shows a significant intrinsic metallicity dispersion at all ages, and no satisfactory fit to any current chemical evolution model. We discuss these results and their implications for the formation and evolution of the SMC

Propiedades qu\uedmicas de estrellas del campo de la Nube Menor de Magallanes

In this paper we analyze the chemical properties of 400 red giant stars belonging to 15 areas spread over the Small Magellanic Cloud (SMC). Metallicities were determined from the equivalent widths of the CaII triplet lines, measured on spectra obtained with the FORS2 instrument at the Very Large Telescope located on Paranal (Chile). We add to this sample other 350 red giant stars previously investigated by our group using the same technique. Using this extended sample, we analyze and discuss the metallicity distribution and the possible existence of a metallicity gradient among the field stars of the SMC. We also compare our results to the chemical properties inferred for the corresponding 30 star clusters of the SMC, whose metallicities have been determined in a homogeneous scale

Age and Metallicity Analysis of the Small Magellanic Cloud from Star Clusters

We present metallicities for 15 Small Magellanic Cloud (SMC) star clusters. We add to this sample the ages and metallicities of 15 additional star clusters previously studied by Parisi et al. (2009) and Parisi et al. (2013), which were observed and analyzed following the same procedures as in the present work. Therefore, we compiled a sample of 30 SMC star clusters homogeneously studied, the largest sample to date. Metallicities are determined from the Calcium II triplet lines (CaT) in spectra obtained using the FORS2 multi-object spectrograph on the VLT (Paranal, Chile). Ages are determined from color-magnitude diagrams built from photometry of the pre-images. Using this sample, we analyze the chemical properties of the SMC, particularly the age-metallicity relation. We found three new old clusters which help to fill the so called SMC \u201cage gap\u201d between L 1 and NGC 121, the 2 oldest previously known clusters. These new old SMC clusters broadly increase our knowledge of the chemical evolution of this galaxy during the earliest epochs