FSR 1716: A New Milky Way Globular Cluster Confirmed Using VVV RR Lyrae Stars
| Autor: | R. K. Saito, Christian Moni-Bidin, Marina Rejkuba, Maren Hempel, Radostin Kurtev, István Dékány, Camila Navarrete, Mike Irwin, Daniel J. Majaess, Tali Palma, Sebastián Ramírez Alegría, Dante Minniti, Eduardo Luiz Damiani Bica, Beatriz Barbuy, Felipe Gran, Charles Jose Bonatto, Francesco Mauro, Douglas Geisler, Jura Borissova, Rodolfo H. Barbá, Valentin D. Ivanov, Márcio Catelan, Bruno Dias, Roger E. Cohen, Rodrigo Contreras-Ramos, Dirk Froebrich, Juan J. Clariá, Manuela Zoccali, Philip W. Lucas, Oscar A. Gonzalez, Anne S. M. Buckner, Julio A. Carballo-Bello, Elena Valenti, Javier Alonso-García, Gergely Hagdu, André-Nicolas Chené, Jim Emerson, Joyce Pullen |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Vista Variables in the Via Lactea
ESTRELAS VARIÁVEIS Milky Way FOS: Physical sciences Astrophysics RR Lyrae variable Globular cluster 01 natural sciences VVV Survey 0103 physical sciences QB460 010303 astronomy & astrophysics Red clump Solar and Stellar Astrophysics (astro-ph.SR) Physics RR Lyrae 010308 nuclear & particles physics Astronomy and Astrophysics Astrophysics - Astrophysics of Galaxies Red-giant branch Distance modulus Star cluster Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) |
| Zdroj: | CONICET Digital (CONICET) Consejo Nacional de Investigaciones Científicas y Técnicas instacron:CONICET Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| ISSN: | 2041-8205 |
| DOI: | 10.3847/2041-8213/838/1/L14/meta |
| Popis: | We use deep multi-epoch near-IR images of the VISTA Variables in the V��a L��ctea (VVV) Survey to search for RR Lyrae stars towards the Southern Galactic plane. Here we report the discovery of a group of RR Lyrae stars close together in VVV tile d025. Inspection of the VVV images and PSF photometry reveals that most of these stars are likely to belong to a globular cluster, that matches the position of the previously known star cluster FSR\,1716. The stellar density map of the field yields a $>100$ sigma detection for this candidate globular cluster, that is centered at equatorial coordinates $RA_{J2000}=$16:10:30.0, $DEC_{J2000}=-$53:44:56; and galactic coordinates $l=$329.77812, $b=-$1.59227. The color-magnitude diagram of this object reveals a well populated red giant branch, with a prominent red clump at $K_s=13.35 \pm 0.05$, and $J-K_s=1.30 \pm 0.05$. We present the cluster RR Lyrae positions, magnitudes, colors, periods and amplitudes. The presence of RR Lyrae indicates an old globular cluster, with age $>10$ Gyr. We classify this object as an Oosterhoff type I globular cluster, based on the mean period of its RR Lyrae type ab, $=0.540$ days, and argue that this is a relatively metal-poor cluster with $[Fe/H] = -1.5 \pm 0.4$ dex. The mean extinction and reddening for this cluster are $A_{K_s}=0.38 \pm 0.02$, and $E(J-K_s)=0.72 \pm 0.02$ 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 mean distance modulus is $(m-M)_0 = 14.38 \pm 0.03$ mag, implying a distance $D = 7.5 \pm 0.2$ kpc, and a Galactocentric distance $R_G=4.3$ kpc. 7 pages, 4 figures. ApJL, in press |
| Databáze: | OpenAIRE |
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