FSR 1716: A New Milky Way Globular Cluster Confirmed Using VVV RR Lyrae Stars

We use deep multi-epoch near-IR images of the VISTA Variables in the Vía Láctea(VVV)Survey to search forRR Lyrae stars toward the Southern Galactic plane. Here, we report the discovery of a group of RR Lyrae starsclose together in VVV tile d025. Inspection of the VVV images and PSF photometry reveal...

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Detalles Bibliográficos
Autores: Minniti, Dante, Palma, Tali, Dékány, Istvan, Hempel, Maren, Rejkuba, Marina, Pullen, Joyce, Alonso-García, Javier, Barba, Rodolfo Hector, Barbuy, Beatriz, Bica, Eduardo, Bonatto, Charles, Borissova, Jura, Catelan, Marcio, Carballo-Bello, Julio A., Chene, Andre Nicolas, Claria Olmedo, Juan Jose, Cohen, Roger E., Contreras Ramos, Rodrigo, Dias, Bruno, Emerson, Jim, Froebrich, Dirk, Buckner, Anne S. M., Geisler, Douglas, Gonzalez, Oscar A., Gran, Felipe, Hagdu, Gergely, Irwin, Mike, Ivanov, Valentin D., Kurtev, Radostin, Lucas, Philip W., Majaess, Daniel, Mauro, Francesco, Moni-Bidin, Christian, Navarrete, Camila, Alegría, Sebastian Ramírez, Saito, Roberto K., Valenti, Elena, Zoccali, Manuela
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2017
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/76842
Acceso en línea:http://hdl.handle.net/11336/76842
Access Level:acceso abierto
Palabra clave:Globular cluster
VVV Survey
RR Lyrae
Milky Way
Descripción
Sumario:We use deep multi-epoch near-IR images of the VISTA Variables in the Vía Láctea(VVV)Survey to search forRR Lyrae stars toward the Southern Galactic plane. Here, we report the discovery of a group of RR Lyrae starsclose together in VVV tile d025. Inspection of the VVV images and PSF photometry reveals that most of thesestars are likely to belong to a globular cluster that matches the position of the previously known star clusterFSR 1716. The stellar density map of thefield yields a>100σdetection for this candidate globular cluster that iscentered at equatorial coordinates R.A.J2000=16:10:30.0, decl.J2000=−53:44:56 and galactic coordinatesl=329.77812,b=−1.59227. The color–magnitude diagram of this object reveals a well-populated red giantbranch, with a prominent red clump atKs=13.35±0.05, andJ−Ks=1.30±0.05. We present the clusterRR Lyrae positions, magnitudes, colors, periods, and amplitudes. The presence of RR Lyrae indicates an oldglobular cluster, with an age>10 Gyr. We classify this object as an Oosterhoff type I globular cluster, based onthe mean period of its RR Lyrae type ab,áñ=P0.540days, and argue that this is a relatively metal-poor clusterwith[Fe/H]=−1.5±0.4 dex. The mean extinction and reddening for this cluster are=A0.38 0.02KsandE(J−Ks)=0.72±0.02 mag, respectively, as measured from the RR Lyrae colors and the near-IR color–magnitude diagram. We also measure the cluster distance using the RR Lyrae type ab stars. The cluster meandistance modulus is(m−M)0=14.38±0.03 mag, implying a distanceD=7.5±0.2 kpc and aGalactocentric distanceRG=4.3 kpc

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