The VMC survey. XI. Radial stellar population gradients in the Galactic globular cluster 47 Tucanae

Chengyuan Li; Richard De Grijs; Licai Deng; Stefano Rubele; Chuchu Wang; Kenji Bekki; Maria Rosa L Cioni; Gisella Clementini; Jim Emerson; Bi Qing For; Leo Girardi; Martin A T Groenewegen; Roald Guandalini; Marco Gullieuszik; Marcella Marconi; Andrés E. Piatti; Vincenzo Ripepi; Jacco Th Van Loon

doi:10.1088/0004-637X/790/1/35

The VMC survey. XI. Radial stellar population gradients in the Galactic globular cluster 47 Tucanae

Chengyuan Li, Richard De Grijs, Licai Deng, Stefano Rubele, Chuchu Wang, Kenji Bekki, Maria Rosa L Cioni, Gisella Clementini, Jim Emerson, Bi Qing For, Leo Girardi, Martin A T Groenewegen, Roald Guandalini, Marco Gullieuszik, Marcella Marconi, Andrés E. Piatti, Vincenzo Ripepi, Jacco Th Van Loon

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Abstract

We present a deep near-infrared color-magnitude diagram of the Galactic globular cluster 47 Tucanae, obtained with the Visible and Infrared Survey Telescope for Astronomy (VISTA) as part of the VISTA near-infrared Y, J, K s survey of the Magellanic System (VMC). The cluster stars comprising both the subgiant and red giant branches exhibit apparent, continuous variations in color-magnitude space as a function of radius. Subgiant branch stars at larger radii are systematically brighter than their counterparts closer to the cluster core; similarly, red-giant-branch stars in the cluster's periphery are bluer than their more centrally located cousins. The observations can very well be described by adopting an age spread of 0.5 Gyr as well as radial gradients in both the cluster's helium abundance (Y) and metallicity (Z), which change gradually from (Y = 0.28, Z = 0.005) in the cluster core to (Y = 0.25, Z = 0.003) in its periphery. We conclude that the cluster's inner regions host a significant fraction of second-generation stars, which decreases with increasing radius; the stellar population in the 47 Tuc periphery is well approximated by a simple stellar population.

Original language	English
Article number	35
Pages (from-to)	1-14
Number of pages	14
Journal	Astrophysical Journal
Volume	790
Issue number	1
DOIs	https://doi.org/10.1088/0004-637X/790/1/35
Publication status	Published - 20 Jul 2014
Externally published	Yes

Bibliographical note

Copyright 2014 The American Astronomical Society. First published in the Astrophysical Journal, 790(1), 35, 2014. The original publication is available at https://doi.org/10.1088/0004-637X/790/1/35, published by IOP Publishing. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

globular clusters: individual (47 Tuc, NGC 104)
Hertzsprung-Russell and C-M diagrams
infrared: stars
stars: Population II

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10.1088/0004-637X/790/1/35

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Li, C., De Grijs, R., Deng, L., Rubele, S., Wang, C., Bekki, K., Cioni, M. R. L., Clementini, G., Emerson, J., For, B. Q., Girardi, L., Groenewegen, M. A. T., Guandalini, R., Gullieuszik, M., Marconi, M., Piatti, A. E., Ripepi, V., & Van Loon, J. T. (2014). The VMC survey. XI. Radial stellar population gradients in the Galactic globular cluster 47 Tucanae. Astrophysical Journal, 790(1), 1-14. Article 35. https://doi.org/10.1088/0004-637X/790/1/35

@article{77bdacbcf2e64e90b1ec39641894cb19,

title = "The VMC survey. XI. Radial stellar population gradients in the Galactic globular cluster 47 Tucanae",

abstract = "We present a deep near-infrared color-magnitude diagram of the Galactic globular cluster 47 Tucanae, obtained with the Visible and Infrared Survey Telescope for Astronomy (VISTA) as part of the VISTA near-infrared Y, J, K s survey of the Magellanic System (VMC). The cluster stars comprising both the subgiant and red giant branches exhibit apparent, continuous variations in color-magnitude space as a function of radius. Subgiant branch stars at larger radii are systematically brighter than their counterparts closer to the cluster core; similarly, red-giant-branch stars in the cluster's periphery are bluer than their more centrally located cousins. The observations can very well be described by adopting an age spread of 0.5 Gyr as well as radial gradients in both the cluster's helium abundance (Y) and metallicity (Z), which change gradually from (Y = 0.28, Z = 0.005) in the cluster core to (Y = 0.25, Z = 0.003) in its periphery. We conclude that the cluster's inner regions host a significant fraction of second-generation stars, which decreases with increasing radius; the stellar population in the 47 Tuc periphery is well approximated by a simple stellar population.",

keywords = "globular clusters: individual (47 Tuc, NGC 104), Hertzsprung-Russell and C-M diagrams, infrared: stars, stars: Population II",

author = "Chengyuan Li and {De Grijs}, Richard and Licai Deng and Stefano Rubele and Chuchu Wang and Kenji Bekki and Cioni, {Maria Rosa L} and Gisella Clementini and Jim Emerson and For, {Bi Qing} and Leo Girardi and Groenewegen, {Martin A T} and Roald Guandalini and Marco Gullieuszik and Marcella Marconi and Piatti, {Andr{\'e}s E.} and Vincenzo Ripepi and {Van Loon}, {Jacco Th}",

note = "Copyright 2014 The American Astronomical Society. First published in the Astrophysical Journal, 790(1), 35, 2014. The original publication is available at https://doi.org/10.1088/0004-637X/790/1/35, published by IOP Publishing. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.",

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Li, C, De Grijs, R, Deng, L, Rubele, S, Wang, C, Bekki, K, Cioni, MRL, Clementini, G, Emerson, J, For, BQ, Girardi, L, Groenewegen, MAT, Guandalini, R, Gullieuszik, M, Marconi, M, Piatti, AE, Ripepi, V & Van Loon, JT 2014, 'The VMC survey. XI. Radial stellar population gradients in the Galactic globular cluster 47 Tucanae', Astrophysical Journal, vol. 790, no. 1, 35, pp. 1-14. https://doi.org/10.1088/0004-637X/790/1/35

TY - JOUR

T1 - The VMC survey. XI. Radial stellar population gradients in the Galactic globular cluster 47 Tucanae

AU - Li, Chengyuan

AU - De Grijs, Richard

AU - Deng, Licai

AU - Rubele, Stefano

AU - Wang, Chuchu

AU - Bekki, Kenji

AU - Cioni, Maria Rosa L

AU - Clementini, Gisella

AU - Emerson, Jim

AU - For, Bi Qing

AU - Girardi, Leo

AU - Groenewegen, Martin A T

AU - Guandalini, Roald

AU - Gullieuszik, Marco

AU - Marconi, Marcella

AU - Piatti, Andrés E.

AU - Ripepi, Vincenzo

AU - Van Loon, Jacco Th

N1 - Copyright 2014 The American Astronomical Society. First published in the Astrophysical Journal, 790(1), 35, 2014. The original publication is available at https://doi.org/10.1088/0004-637X/790/1/35, published by IOP Publishing. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

PY - 2014/7/20

Y1 - 2014/7/20

N2 - We present a deep near-infrared color-magnitude diagram of the Galactic globular cluster 47 Tucanae, obtained with the Visible and Infrared Survey Telescope for Astronomy (VISTA) as part of the VISTA near-infrared Y, J, K s survey of the Magellanic System (VMC). The cluster stars comprising both the subgiant and red giant branches exhibit apparent, continuous variations in color-magnitude space as a function of radius. Subgiant branch stars at larger radii are systematically brighter than their counterparts closer to the cluster core; similarly, red-giant-branch stars in the cluster's periphery are bluer than their more centrally located cousins. The observations can very well be described by adopting an age spread of 0.5 Gyr as well as radial gradients in both the cluster's helium abundance (Y) and metallicity (Z), which change gradually from (Y = 0.28, Z = 0.005) in the cluster core to (Y = 0.25, Z = 0.003) in its periphery. We conclude that the cluster's inner regions host a significant fraction of second-generation stars, which decreases with increasing radius; the stellar population in the 47 Tuc periphery is well approximated by a simple stellar population.

AB - We present a deep near-infrared color-magnitude diagram of the Galactic globular cluster 47 Tucanae, obtained with the Visible and Infrared Survey Telescope for Astronomy (VISTA) as part of the VISTA near-infrared Y, J, K s survey of the Magellanic System (VMC). The cluster stars comprising both the subgiant and red giant branches exhibit apparent, continuous variations in color-magnitude space as a function of radius. Subgiant branch stars at larger radii are systematically brighter than their counterparts closer to the cluster core; similarly, red-giant-branch stars in the cluster's periphery are bluer than their more centrally located cousins. The observations can very well be described by adopting an age spread of 0.5 Gyr as well as radial gradients in both the cluster's helium abundance (Y) and metallicity (Z), which change gradually from (Y = 0.28, Z = 0.005) in the cluster core to (Y = 0.25, Z = 0.003) in its periphery. We conclude that the cluster's inner regions host a significant fraction of second-generation stars, which decreases with increasing radius; the stellar population in the 47 Tuc periphery is well approximated by a simple stellar population.

KW - globular clusters: individual (47 Tuc, NGC 104)

KW - Hertzsprung-Russell and C-M diagrams

KW - infrared: stars

KW - stars: Population II

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DO - 10.1088/0004-637X/790/1/35

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SN - 0004-637X

VL - 790

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EP - 14

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

M1 - 35

ER -

The VMC survey. XI. Radial stellar population gradients in the Galactic globular cluster 47 Tucanae

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Bibliographical note

Keywords

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