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Title: FSR 1716: a new Milky Way globular cluster confirmed using VVV RR Lyrae stars

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.{sub J2000} = 16:10:30.0, decl.{sub 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 {sub s} = 13.35 ± 0.05, and J − K {sub 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, 〈P〉=0.540 days, and arguemore » 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{sub K{sub s}}=0.38±0.02 and E(J − K {sub 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){sub 0} = 14.38 ± 0.03 mag, implying a distance D = 7.5 ± 0.2 kpc and a Galactocentric distance R {sub G} = 4.3 kpc.« less

Authors:
 [1]; ;  [2];  [3]; ; ;  [4];  [5];  [6];  [7];  [8]; ;  [9];  [10];  [11];
  1. Departamento de Física, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. Fernandez Concha 700, Las Condes, Santiago (Chile)
  2. Instituto Milenio de Astrofísica, Santiago (Chile)
  3. Astronomisches Rechen-Institut, Zentrum fuer Astronomie der Universitaet Heidelberg, Moenchhofstr. 12-14, D-69120 Heidelberg (Germany)
  4. Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Av. Vicuña Mackenna 4860, Santiago (Chile)
  5. European Southern Observatory, Karl-Schwarszchild-Str. 2, D-85748 Garching bei Muenchen (Germany)
  6. Unidad de Astronomia, Facultad Cs. Básicas, Universidad de Antofagasta, Avda. U. de Antofagasta 02800, Antofagasta (Chile)
  7. Departamento de Física y Astronomía, Universidad de la Serena, Av. Juan Cisternas 1200 Norte, La Serena (Chile)
  8. Dept. of Astronomy, University of Sao Paulo, Sao Paulo (Brazil)
  9. Universidade Federal do Rio Grande do Sul (Brazil)
  10. Instituto de Física y Astronomía, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Casilla 5030, Valparaíso (Chile)
  11. Gemini Observatory, Northern Operations Center, 670 North A’ohoku Place, Hilo, HI 96720 (United States)
Publication Date:
OSTI Identifier:
22869172
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 838; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; COLOR; DETECTION; DIAGRAMS; METALS; MILKY WAY; NEAR INFRARED RADIATION; PHOTOMETRY; STAR CLUSTERS

Citation Formats

Minniti, Dante, Palma, Tali, Pullen, Joyce, Dékány, Istvan, Hempel, Maren, Catelan, Marcio, Carballo-Bello, Julio A., Rejkuba, Marina, Alonso-García, Javier, Barbá, Rodolfo, Barbuy, Beatriz, Bica, Eduardo, Bonatto, Charles, Borissova, Jura, Chene, Andre Nicolas, and others, and. FSR 1716: a new Milky Way globular cluster confirmed using VVV RR Lyrae stars. United States: N. p., 2017. Web. doi:10.3847/2041-8213/838/1/L14.
Minniti, Dante, Palma, Tali, Pullen, Joyce, Dékány, Istvan, Hempel, Maren, Catelan, Marcio, Carballo-Bello, Julio A., Rejkuba, Marina, Alonso-García, Javier, Barbá, Rodolfo, Barbuy, Beatriz, Bica, Eduardo, Bonatto, Charles, Borissova, Jura, Chene, Andre Nicolas, & others, and. FSR 1716: a new Milky Way globular cluster confirmed using VVV RR Lyrae stars. United States. https://doi.org/10.3847/2041-8213/838/1/L14
Minniti, Dante, Palma, Tali, Pullen, Joyce, Dékány, Istvan, Hempel, Maren, Catelan, Marcio, Carballo-Bello, Julio A., Rejkuba, Marina, Alonso-García, Javier, Barbá, Rodolfo, Barbuy, Beatriz, Bica, Eduardo, Bonatto, Charles, Borissova, Jura, Chene, Andre Nicolas, and others, and. Mon . "FSR 1716: a new Milky Way globular cluster confirmed using VVV RR Lyrae stars". United States. https://doi.org/10.3847/2041-8213/838/1/L14.
@article{osti_22869172,
title = {FSR 1716: a new Milky Way globular cluster confirmed using VVV RR Lyrae stars},
author = {Minniti, Dante and Palma, Tali and Pullen, Joyce and Dékány, Istvan and Hempel, Maren and Catelan, Marcio and Carballo-Bello, Julio A. and Rejkuba, Marina and Alonso-García, Javier and Barbá, Rodolfo and Barbuy, Beatriz and Bica, Eduardo and Bonatto, Charles and Borissova, Jura and Chene, Andre Nicolas and others, and},
abstractNote = {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.{sub J2000} = 16:10:30.0, decl.{sub 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 {sub s} = 13.35 ± 0.05, and J − K {sub 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, 〈P〉=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{sub K{sub s}}=0.38±0.02 and E(J − K {sub 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){sub 0} = 14.38 ± 0.03 mag, implying a distance D = 7.5 ± 0.2 kpc and a Galactocentric distance R {sub G} = 4.3 kpc.},
doi = {10.3847/2041-8213/838/1/L14},
url = {https://www.osti.gov/biblio/22869172}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 838,
place = {United States},
year = {2017},
month = {3}
}