New galactic star clusters discovered in the VVV survey. Candidates projected on the inner disk and bulge^⋆

¹ Departamento de Física y AstronomíaFacultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Casilla 5030, Valparaíso, Chile
e-mail: jura.borissova@uv.cl
² Gemini Observatory, Northern Operations Centre, 670 North A’ohoku Place, Hilo, HI 96720, USA
e-mail: andrenicolas.chene@gmail.com
³ Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, 263 129 Nainital, India
e-mail: saurabh175@gmail.com
⁴ Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
e-mail: ignacio.negueruela@ua.es
⁵ Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Casilla 306 Santiago 22, Chile
e-mail: dante@astro.puc.cl; mcatean@astro.puc.cl
⁶ Universidade Federal do Rio Grande do Sul, Departamento de Astronomia CP 15051, RS, 91501-970 Porto Alegre, Brazil
e-mail: charles@if.ufrgs.br
⁷ Departamento de Astronomía, Casilla 160-C Concepción, Universidad de Concepción, Chile
e-mail: dgeisler@astro-udec.cl
⁸ Department of Physics, University of Cincinnati, Cincinnati, OH 45221-0011, USA
e-mail: margaret.hanson@uc.edu; bogdan.popescu@uc.edu
⁹ European Southern Observatory, Ave. Alonso de Cordova 3107, Casilla 19 Santiago 19001, Chile
e-mail: vivanov@eso.org
¹⁰ Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UK
e-mail: p.w.lucas@herts.ac.uk
¹¹ Department of Astronomy & Physics, Saint Mary’s University, Halifax, NS B3H 3C3; Mount Saint Vincent University, Halifax, NS B3M 2J6, Canada
e-mail: dmajaess@ns.sympatico.ca
¹² Instituto de Astronomia, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta, Chile
e-mail: cmoni@ucn.cl
¹³ Universidade Federal de Sergipe, Departamento de Física, Av. Marechal Rondon s/n, 49100-000 São Cristóvão, SE, Brazil
e-mail: robsaito@gmail.com
¹⁴ Vatican Observatory, V 00120 Vatican City State, Italy
¹⁵ Millennium Institute of Astrophysics  

Received: 13 August 2013
Accepted: 8 June 2014

Abstract

Context. VISTA Variables in the Vía Láctea (VVV) is one of six ESO Public Surveys using the 4 meter Visible and Infrared Survey Telescope for Astronomy (VISTA). The VVV survey covers the Milky Way bulge and an adjacent section of the disk, and one of the principal objectives is to search for new star clusters within previously unreachable obscured parts of the Galaxy.

Aims. The primary motivation behind this work is to discover and analyze obscured star clusters in the direction of the inner Galactic disk and bulge.

Methods. Regions of the inner disk and bulge covered by the VVV survey were visually inspected using composite JHK_S color images to select new cluster candidates on the basis of apparent overdensities. DR1, DR2, CASU, and point spread function photometry of 10 × 10 arcmin fields centered on each candidate cluster were used to construct color–magnitude and color–color diagrams. Follow-up spectroscopy of the brightest members of several cluster candidates was obtained in order to clarify their nature.

Results. We report the discovery of 58 new infrared cluster candidates. Fundamental parameters such as age, distance, and metallicity were determined for 20 of the most populous clusters.