Browsing by Author "Geisler, D."
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- ItemA Chemical and Kinematical Analysis of the Intermediate-age Open Cluster IC 166 from APOGEE and Gaia DR2(2018) Schiappacasse-Ulloa, J.; Tang, B.; Fernandez-Trincado, J. G.; Zamora, O.; Geisler, D.; Frinchaboy, P.; Schultheis, M.; Dell'Agli, F.; Villanova, S.; Masseron, T.; Meszaros, Sz; Souto, D.; Hasselquist, S.; Cunha, K.; Smith, V. V.; Garcia-Hernandez, D. A.; Vieira, K.; Robin, A. C.; Minniti, D.; Zasowski, G.; Moreno, E.; Perez-Villegas, A.; Lane, R. R.; Ivans, I. I.; Pan, K.; Nitschelm, C.; Santana, F. A.; Carrera, R.; Roman-Lopes, A.
- ItemA colour-excess extinction map of the southern Galactic disc from the VVV and GLIMPSE surveys(2019) Soto, M.; Barba, R.; Minniti, D.; Kunder, A.; Majaess, D.; Nilo Castellon, J. L.; Alonso García, J.; Leone, G.; Contreras Ramos, Rodrigo Andrés; Hempel, Maren; Morelli, Lorenzo; Haikala, L.; Firpo, V.; Lucas, P.; Emerson, J. P.; Bidin, C. M.; Geisler, D.; Saito, R. K.; Gurovich, S.; Rejkuba, M.; Barbieri, M.; Román Lopes, A.; Alonso, M. V.; Baravalle, L. D.; Borissova, J.; Kurtev, R.; Milla, F
- ItemA HOT HORIZONTAL BRANCH STAR WITH A CLOSE K-TYPE MAIN-SEQUENCE COMPANION(2015) Bidin, C. Moni; Momany, Y.; Montalto, M.; Catelan, Márcio; Villanova, S.; Piotto, G.; Geisler, D.
- ItemAtypical Mg-poor Milky Way Field Stars with Globular Cluster Second-generation-like Chemical Patterns(2017) Fernández Trincado J.; Zamora, O.; García Hernández, D.; Souto, D.; Dell'Agli, F.; Schiavon, R.; Geisler, D.; Tang, B.; Villanova, S.; Chanamé, Julio; Hasselquist, S.; Mennickent, R.; Cunha, K.; Shetrone, M.; Prieto, C.; Vieira, K.; Zasowski, G.; Sobeck, J.; Hayes, C.; Majewski, S.; Placco, V.; Beers, T.; Schleicher, D.; Robin, A.; Mészáros, S.; Masseron, T.; Pérez, A.; Anders, F.; Meza, A.; Alves-Brito A.; Carrera, R.; Minniti, D.; Lane, R.; Fernández-Alvar E.; Moreno, E.; Pichardo, B.; Pérez-Villegas, A.; Schultheis, M.; Roman-Lopes, A.; Fuentes, C.; Nitschelm, C.; Harding, P.; Bizyaev, D.; Pan, K.; Oravetz, D.; Simmons, A.; Ivans, I.; Blanco-Cuaresma, S.; Hernández J.; Alonso-García, J.; Valenzuela, O.
- ItemBaade's window and APOGEE Metallicities, ages, and chemical abundances(2017) Schultheis, M.; Rojas Arriagada, Alvaro; Pérez, A. E. García; Jönsson, H.; Hayden, M.; Nandakumar, G.; Cunha, K.; Prieto, C. Allende; Holtzman, J. A.; Beers, T. C.; Bizyaev, D.; Brinkmann, J.; Carrera, R.; Cohen, R. E.; Geisler, D.; Hearty, F. R.; Fernández-Trincado, J. G.; Maraston, C.; Minniti, D.; Nitschelm, C.; Roman-Lopes, A.; Schneider, D. P.; Tang, B.; Villanova, S.; Zasowski, G.; Majewski, S. R.
- 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....
- ItemChemical abundances of giant stars in NGC 5053 and NGC 5634, two globular clusters associated with the Sagittarius dwarf spheroidal galaxy?(EDP SCIENCES S A, 2015) Sbordone, L.; Monaco, L.; Moni Bidin, C.; Bonifacio, P.; Villanova, S.; Bellazzini, M.; Ibata, R.; Chiba, M.; Geisler, D.; Caffau, E.; Duffau, S.Context. The tidal disruption of the Sagittarius dwarf spheroidal galaxy (Sgr dSph) is producing the most prominent substructure in the Milky Way (MW) halo, the Sagittarius Stream. Aside from field stars, it is suspected that the Sgr dSph has lost a number of globular clusters (GC). Many Galactic GC are thought to have originated in the Sgr dSph. While for some candidates an origin in the Sgr dSph has been confirmed owing to chemical similarities, others exist whose chemical composition has never been investigated.
- ItemDeriving metallicities from calcium triplet spectroscopy in combination with near-infrared photometry(2014) Mauro, F.; Moni Bidin, Christian; Geisler, D.; Saviane, I.; Da Costa, G.; Gormaz Matamala, A.; Chene, A.; Cohen, R.; Dias, B.; Vásquez Godoy, Sergio Osmán
- ItemDetailed abundances in stars belonging to ultra-faint dwarf spheroidal galaxies(2012) François, P.; Monaco, L.; Villanova, S.; Catelan, Márcio; Bonifacio, P.; Bellazzini, M.; Moni Bidin, C.; Marconi, G.; Geisler, D.; Sbordone, L.We report preliminary results concerning the detailed chemical composition of metal poor stars belonging to close ultra-faint dwarf galaxies (hereafter UfDSphs). The abundances have been determined thanks to spectra obtained with X-Shooter, a high efficiency spectrograph installed on one of the ESO VLT units. The sample of ultra-faint dwarf spheroidal stars have abundance ratios slightly lower to what is measured in field halo star of the same metallicity. We did not find extreme abundances in our Hercules stars as the one found by Koch for his 2 Hercules stars. The synthesis of the neutron capture elements Ba and Sr seems to originate from the same nucleosynthetic process in operation during the early stages of the galactic evolution....
- ItemDiscovery of a thin stellar stream in the SLAMS survey(2018) Jethwa, P.; Torrealba, G.; Navarrete, C.; Carballo-Bello, J. A.; de Boer, T.; Erkal, D.; Koposov, S. E.; Duffau, S.; Geisler, D.; Catelan, Márcio; Belokurov, V.
- ItemDiscovery of VVV CL001 A low-mass globular cluster next to UKS 1 in the direction of the Galactic bulge(EDP SCIENCES S A, 2011) Minniti, D.; Hempel, M.; Toledo, I.; Ivanov, V. D.; Alonso Garcia, J.; Saito, R. K.; Catelan, M.; Geisler, D.; Jordan, A.; Borissova, J.; Zoccali, M.; Kurtev, R.; Carraro, G.; Barbuy, B.; Claria, J.; Rejkuba, M.; Emerson, J.; Moni Bidin, C.Context. It is not known how many globular clusters may remain undetected towards the Galactic bulge.
- ItemEstudio infrarrojo de cúmulos inmersos en l = 345°(2011) Baume, G.; Feinstein, C.; Borissova, J.; Kurtev, R.; Chené, A. -N.; Moni Bidin, C.; Mauro, F.; Bonatto, C.; Bica, E.; Clarke, J. R. A.; Catelan, Márcio; Geisler, D.; Minniti, D.; Lucas, P. W.We have studied several embedded star clusters located in the fourth quad- rant of the Galactic plane (l 345 ; b +1.5 ). Data involves photometry and infrared spectroscopy (bands JHK and low dispersion respectively). This analysis has yielded a preliminary estimate of the fundamental param- eters of these objects and the behavior of the interstellar medium in this Galactic direction. FULL TEXT IN SPANISH...
- ItemInvestigando cúmulos estelares masivos con el VVV(2011) Chené, A. -N.; Clarke, J. R. A.; Borissova, J.; Moni Bidin, C.; Mauro, F.; Bonatto, C.; Kurtev, R.; Baume, G.; Feinstein, C.; Minniti, D.; Catelan, Márcio; Lucas, P. W.; Geisler, D.Preliminary results are presented for the study of infrared data of three mas- sive stellar clusters. Have been combined photometric observations (JHK; VVV project = Vista Variables in the Vía Láctea) and spectroscopic (follow- up) observations of the brightest stars in these clusters. In this way we have been able to refine the values of distance, reddening, age and masses of the involved objects. FULL TEXT IN SPANISH...
- ItemInvestigating potential planetary nebula/cluster pairs(2014) Moni Bidin, C.; Majaess, D.; Bonatto, C.; Mauro, F.; Turner, D.; Gieren Waiblinger, Wolfgang Paul; Chené, A.N.; Gormaz-Matamala, A.C.; Borissova, J.; Minniti, D.; Kurtev, R.G.; Carraro, G.; Gieren Waiblinger, Wolfgang Paul; Moni Bidin, C.; Majaess, D.; Bonatto, C.; Mauro, F.; Turner, D.; Geisler, D.; Chené, A.N.; Gormaz-Matamala, A.C.; Borissova, J.; Minniti, D.; Kurtev, R.G.; Carraro, G.; Gieren Waiblinger, Wolfgang Paul
- ItemMassive open star clusters using the VVV survey. III. A young massive cluster at the far edge of the Galactic bar(2014) Ramírez Alegría, S.; Borissova, J.; Chené, A. N.; O'Leary, E.; Amigo, P.; Minniti, D.; Saito, R. K.; Geisler, D.; Kurtev, R.; Hempel, M.; Gromadzki, M.; Clarke, J. R. A.; Negueruela, I.; Marco, A.; Fierro, C.; Bonatto, C.; Catelan, MárcioContext. Young massive clusters are key to map the Milky Way's structure, and near-infrared large area sky surveys have contributed strongly to the discovery of new obscured massive stellar clusters. Aims: We present the third article in a series of papers focused on young and massive clusters discovered in the VVV survey. This article is dedicated to the physical characterization of VVV CL086, using part of its OB-stellar population. Methods: We physically characterized the cluster using JHKS near-infrared photometry from ESO public survey VVV images, using the VVV-SkZ pipeline, and near-infrared K-band spectroscopy, following the methodology presented in the first article of the series. Results: Individual distances for two observed stars indicate that the cluster is located at the far edge of the Galactic bar. These stars, which are probable cluster members from the statistically field-star decontaminated CMD, have spectral types between O9 and B0 V. According to our analysis, this young cluster (1.0 Myr < age < 5.0 Myr) is located at a distance of 11+5-6 kpc, and we estimate a lower limit for the cluster total mass of (2.8+1.6-1.4) · 103 M⊙. It is likely that the cluster contains even earlier and more massive stars. Based on observations taken within the ESO VISTA Public Survey VVV (programme ID 179.B-2002), and with ISAAC, VLT, ESO (programme 087.D-0341A).Near-IR photometry of the most probable cluster members is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/564/L9...
- ItemNew Galactic star cluster candidates discovered in the VVV Survey within 10 degrees around the Galactic center(2011) Borissova, J.; Clarke, J. R. A.; Bonatto, C.; Chené, A. -N.; Bica, E.; Kurtev, R.; Barbá, R.; Minniti, D.; Peñaloza, F.; Catelan, Márcio; Lucas, P. W.; Mauro, F.; Moni Bidin, C.; Geisler, D.; Ivanov, V. D.; Baume, G.; Feinstein, C.We report the discovery of 57 new infrared open cluster candidates and stel- lar groups in the inner 10 degrees around the Galactic center. The newly dis- covered candidates are found by visual inspection of near infrared images observed under the Vista Variables in the Via Lactea (VVV) ESO Large Public Survey. The preliminary analysis shows that approximately 1/3 of them are younger than 10 Myrs....
- ItemNew VVV Survey Globular Cluster Candidates in the Milky Way Bulge(2017) Minniti, D.; Geisler, D.; Alonso, J.; Palma, T.; Beamin, J.; Borissova, J.; Catelan, Márcio; Claria, J.; Hempel, Maren; Contreras Ramos, Rodrigo Andrés; Cohen, R.; Días, B.; Fernández, J.; Gómez, M.; Ivanov, V.; Kurtev, R.
- ItemSpectroscopy of blue horizontal branch stars in NGC 6656 (M 22)(2013) Salgado, C.; Bidin, C.; Villanova, S.; Geisler, D.; Catelan, Márcio
- ItemThe chemical compositions of accreted and in situ galactic globular clusters according to SDSS/APOGEE(2020) Horta, D.; Schiavon, R. P.; Mackereth, J. T.; Beers, T. C.; Fernández-Trincado, J. G.; Frinchaboy, P. M.; García-Hernández, D. A.; Geisler, D.; Hasselquist, S.; Jönsson, H.; Lane Richard Reade; Majewski, S. R.; Mészáros, S.; Bidin, C. M.; Nataf, D. M.; Roman-Lopes, A.; Nitschelm, C.; Vargas-González, J.; Zasowsk, G.Studies of the kinematics and chemical compositions of Galactic globular clusters (GCs) enable the reconstruction of the history of star formation, chemical evolution, and mass assembly of the Galaxy. Using the latest data release (DR16) of the SDSS/APOGEE survey, we identify 3090 stars associated with 46 GCs. Using a previously defined kinematic association, we break the sample down into eight separate groups and examine how the kinematics-based classification maps into chemical composition space, considering only α (mostly Si and Mg) elements and Fe. Our results show that (i) the loci of both in situ and accreted subgroups in chemical space match those of their field counterparts; (ii) GCs from different individual accreted subgroups occupy the same locus in chemical space. This could either mean that they share a similar origin or that they are associated with distinct satellites which underwent similar chemical enrichment histories; (iii) the chemical compositions of the GCs associated with the low orbital energy subgroup defined by Massari and collaborators is broadly consistent with an in situ origin. However, at the low-metallicity end, the distinction between accreted and in situ populations is blurred; (iv) regarding the status of GCs whose origin is ambiguous, we conclude the following: the position in Si–Fe plane suggests an in situ origin for Liller 1 and a likely accreted origin for NGC 5904 and NGC 6388. The case of NGC 288 is unclear, as its orbital properties suggest an accretion origin, its chemical composition suggests it may have formed in situ.
- ItemThe Gaia-ESO Survey Mg-Al anti-correlation in iDR4 globular clusters(EDP SCIENCES S A, 2017) Pancino, E.; Romano, D.; Tang, B.; Tautvaisiene, G.; Casey, A. R.; Gruyters, P.; Geisler, D.; San Roman, I.; Randich, S.; Alfaro, E. J.; Bragaglia, A.; Flaccomio, E.; Korn, A. J.; Recio Blanco, A.; Smiljanic, R.; Carraro, G.; Bayo, A.; Costado, M. T.; Damiani, F.; Jofre, P.; Lardo, C.; de laverny, P.; Monaco, L.; Morbidelli, L.; Sbordone, L.; Sousa, S. G.; Villanova, S.We use Gaia-ESO (GES) Survey iDR4 data to explore the Mg-Alanti-correlation in globular clusters that were observed as calibrators, as a demonstration of the quality of Gaia-ESO Survey data and analysis. The results compare well with the available literature, within 0.1 dex or less, after a small (compared to the internal spreads) off set between the UVES and GIRAFFE data of 0.10-0.15 dex was taken into account. In particular, for the first time we present data for NGC 5927, which is one of the most metal-rich globular clusters studied in the literature so far with [Fe/H] = -0.39 +/- 0.04 dex; this cluster was included to connect with the open cluster regime in the Gaia-ESO Survey internal calibration. The extent and shape of the Mg-Al anti-correlation provide strong constraints on the multiple population phenomenon in globular clusters. In particular, we studied the dependency of the Mg-Al anti-correlation extension with metallicity, present-day mass, and age of the clusters, using GES data in combination with a large set of homogenized literature measurements. We find a dependency with both metallicity and mass, which is evident when fitting for the two parameters simultaneously, but we do not find significant dependency with age. We confirm that the Mg-Al anti-correlation is not seen in all clusters, but disappears for the less massive or most metal-rich clusters. We also use our data set to see whether a normal anti-correlation would explain the low [Mg/ff] observed in some extragalactic globular clusters, but find that none of the clusters in our sample can reproduce it; a more extreme chemical composition, such as that of NGC 2419, would be required. We conclude that GES iDR4 data already meet the requirements set by the main survey goals and can be used to study globular clusters in detail, even if the analysis procedures were not specifically designed for them.