Minniti, D, Palma, T, Dékány, I et al. (35 more authors) (2017) FSR 1716: A New Milky Way Globular Cluster Confirmed Using VVV RR Lyrae Stars. The Astrophysical Journal Letters, 838 (1). L14. ISSN 2041-8205
Abstract
We use deep multi-epoch near-IR images of the VISTA Variables in the Vía Láctea (VVV) Survey to search for RR Lyrae stars toward 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 >100σ detection for this candidate globular cluster that is centered at equatorial coordinates R.A. J2000 = 16:10:30.0, decl. 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 ± 0.05, and J − K s = 1.30 ± 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 an 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, $\langle P\rangle =0.540$ days, and argue that this is a relatively metal-poor cluster with [Fe/H] = −1.5 ± 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 ± 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 ± 0.03 mag, implying a distance D = 7.5 ± 0.2 kpc and a Galactocentric distance R G = 4.3 kpc.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017, The American Astronomical Society. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | globular clusters: general; galaxies: photometry; stars: variables: RR Lyrae |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Mar 2019 14:39 |
Last Modified: | 06 Mar 2019 14:39 |
Status: | Published |
Publisher: | American Astronomical Society |
Identification Number: | 10.3847/2041-8213/838/1/L14 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:143280 |