Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations

J. Skottfelt; D. M. Bramich; R. Figuera Jaimes; U. G. Jørgensen; N. Kains; A. Arellano Ferro; K. A. Alsubai; V. Bozza; S. Calchi Novati; S. Ciceri; G. D'Ago; M. Dominik; P. Galianni; S.-H. Gu; K. B. W. Harpsøe; T. Haugbølle; T. C. Hinse; M. Hundertmark; D. Juncher; H. Korhonen; C. Liebig; L. Mancini; A. Popovas; M. Rabus; S. Rahvar; G. Scarpetta; R. W. Schmidt; C. Snodgrass; J. Southworth; D. Starkey; R. A. Street; J. Surdej; X.-B. Wang; O. Wertz (The Mindstep Consortium)

doi:10.1051/0004-6361/201424967

Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations

J. Skottfelt, D. M. Bramich, R. Figuera Jaimes, U. G. Jørgensen, N. Kains, A. Arellano Ferro, K. A. Alsubai, V. Bozza, S. Calchi Novati, S. Ciceri, G. D'Ago, M. Dominik, P. Galianni, S.-H. Gu, K. B. W. Harpsøe, T. Haugbølle, T. C. Hinse, M. Hundertmark, D. Juncher, H. KorhonenC. Liebig, L. Mancini, A. Popovas, M. Rabus, S. Rahvar, G. Scarpetta, R. W. Schmidt, C. Snodgrass, J. Southworth, D. Starkey, R. A. Street, J. Surdej, X.-B. Wang, O. Wertz (The Mindstep Consortium)

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

Abstract

Aims. In this paper, we present the analysis of time-series observations from 2013 and 2014 of five metal-rich ([Fe/H] > −1) globular clusters: NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652. The data have been used to perform a census of the variable stars in the central parts of these clusters.

Methods. The observations were made with the electron-multiplying charge-couple device (EMCCD) camera at the Danish 1.54 m Telescope at La Silla, Chile, and they were analysed using difference image analysis to obtain high-precision light curves of the variable stars.

Results. It was possible to identify and classify all of the previously known or suspected variable stars in the central regions of the five clusters. Furthermore, we were able to identify and, in most cases, classify 48, 49, 7, 8, and 2 previously unknown variables in NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652, respectively. Especially interesting is the case of NGC 6441, for which the variable star population of about 150 stars has been thoroughly examined by previous studies, including a Hubble Space Telescope study. In this paper we are able to present 49 new variable stars for this cluster, of which one (possibly two) are RR Lyrae stars, two are W Virginis stars, and the rest are long-period semi-regular or irregular variables on the red giant branch. We have also detected the first double-mode RR Lyrae in the cluster.

Original language	English
Number of pages	23
Journal	Astronomy & Astrophysics
Volume	573
Early online date	6 Jan 2015
DOIs	https://doi.org/10.1051/0004-6361/201424967
Publication status	Published - Jan 2015

Keywords

Globular clusters: individual:
Stars: variables: RR Lyrae
Stars: variables: general
Instrumentation: high angular resolution

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10.1051/0004-6361/201424967

Jaimes_2015_A&A_Searching
Reproduced with permission from Astronomy & Astrophysics, © ESO 2015. This work is made available online in accordance with the publisher’s policies. The final published version of this work is available at http://dx.doi.org/10.1051/0004-6361/201424967
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Cite this

Skottfelt, J., Bramich, D. M., Figuera Jaimes, R., Jørgensen, U. G., Kains, N., Arellano Ferro, A., Alsubai, K. A., Bozza, V., Calchi Novati, S., Ciceri, S., D'Ago, G., Dominik, M., Galianni, P., Gu, S.-H., Harpsøe, K. B. W., Haugbølle, T., Hinse, T. C., Hundertmark, M., Juncher, D., ... Wertz (The Mindstep Consortium), O. (2015). Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations. Astronomy & Astrophysics, 573. https://doi.org/10.1051/0004-6361/201424967

@article{9c4a4e83fbaa4385b7c1f26b365cc5bc,

title = "Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations",

abstract = "Aims. In this paper, we present the analysis of time-series observations from 2013 and 2014 of five metal-rich ([Fe/H] > −1) globular clusters: NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652. The data have been used to perform a census of the variable stars in the central parts of these clusters.Methods. The observations were made with the electron-multiplying charge-couple device (EMCCD) camera at the Danish 1.54 m Telescope at La Silla, Chile, and they were analysed using difference image analysis to obtain high-precision light curves of the variable stars.Results. It was possible to identify and classify all of the previously known or suspected variable stars in the central regions of the five clusters. Furthermore, we were able to identify and, in most cases, classify 48, 49, 7, 8, and 2 previously unknown variables in NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652, respectively. Especially interesting is the case of NGC 6441, for which the variable star population of about 150 stars has been thoroughly examined by previous studies, including a Hubble Space Telescope study. In this paper we are able to present 49 new variable stars for this cluster, of which one (possibly two) are RR Lyrae stars, two are W Virginis stars, and the rest are long-period semi-regular or irregular variables on the red giant branch. We have also detected the first double-mode RR Lyrae in the cluster. ",

keywords = "Globular clusters: individual:, Stars: variables: RR Lyrae, Stars: variables: general, Instrumentation: high angular resolution",

author = "J. Skottfelt and Bramich, {D. M.} and {Figuera Jaimes}, R. and J{\o}rgensen, {U. G.} and N. Kains and {Arellano Ferro}, A. and Alsubai, {K. A.} and V. Bozza and {Calchi Novati}, S. and S. Ciceri and G. D'Ago and M. Dominik and P. Galianni and S.-H. Gu and Harps{\o}e, {K. B. W.} and T. Haugb{\o}lle and Hinse, {T. C.} and M. Hundertmark and D. Juncher and H. Korhonen and C. Liebig and L. Mancini and A. Popovas and M. Rabus and S. Rahvar and G. Scarpetta and Schmidt, {R. W.} and C. Snodgrass and J. Southworth and D. Starkey and Street, {R. A.} and J. Surdej and X.-B. Wang and {Wertz (The Mindstep Consortium)}, O.",

note = "D.M.B. and K.A.A. acknowledge support from NPRP grant # X-019-1-006 from the Qatar National Research Fund (a member of Qatar Foundation). A.A.F. acknowledges the support from DGAPA-UNAM grant through project IN104612. K.A.A., C.L., M.D., K.H. and M.H. acknowledge grant NPRP-09-476-1-78 from the Qatar National Research Fund (a member of Qatar Foundation). CS has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 268421. S.H.G. and X.B.W. would like to thank the financial support from National Natural Science Foundation of China through grants Nos. 10373023, 10773027 and 11333006. T.H. is supported by a Sapere Aude Starting Grant from The Danish Council for Independent Research. T.C.H. acknowledges support from the Korea Research Council of Fundamental Science & Technology (KRCF) via the KRCF Young Scientist Research Fellowship Programme and for financial support from KASI travel grant number 2013-9-400-00. H.K. acknowledges the support from the European Commission under the Marie Curie IEF Programme in FP7. M.R. acknowledges support from FONDECYT postdoctoral fellowship No. 3120097. O.W. (FNRS research fellow) and J. Surdej acknowledge support from the Communaut{\'e} francaise de Belgique - Actions de recherche concert{\'e}es – Acad{\'e}mie Wallonie-Europe. Date of Acceptance: 31/10/2014",

year = "2015",

month = jan,

doi = "10.1051/0004-6361/201424967",

language = "English",

volume = "573",

journal = "Astronomy & Astrophysics",

issn = "0004-6361",

publisher = "EDP SCIENCES S A",

}

Skottfelt, J, Bramich, DM, Figuera Jaimes, R, Jørgensen, UG, Kains, N, Arellano Ferro, A, Alsubai, KA, Bozza, V, Calchi Novati, S, Ciceri, S, D'Ago, G, Dominik, M, Galianni, P, Gu, S-H, Harpsøe, KBW, Haugbølle, T, Hinse, TC, Hundertmark, M, Juncher, D, Korhonen, H, Liebig, C, Mancini, L, Popovas, A, Rabus, M, Rahvar, S, Scarpetta, G, Schmidt, RW, Snodgrass, C, Southworth, J, Starkey, D, Street, RA, Surdej, J, Wang, X-B & Wertz (The Mindstep Consortium), O 2015, 'Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations', Astronomy & Astrophysics, vol. 573. https://doi.org/10.1051/0004-6361/201424967

TY - JOUR

T1 - Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations

AU - Skottfelt, J.

AU - Bramich, D. M.

AU - Figuera Jaimes, R.

AU - Jørgensen, U. G.

AU - Kains, N.

AU - Arellano Ferro, A.

AU - Alsubai, K. A.

AU - Bozza, V.

AU - Calchi Novati, S.

AU - Ciceri, S.

AU - D'Ago, G.

AU - Dominik, M.

AU - Galianni, P.

AU - Gu, S.-H.

AU - Harpsøe, K. B. W.

AU - Haugbølle, T.

AU - Hinse, T. C.

AU - Hundertmark, M.

AU - Juncher, D.

AU - Korhonen, H.

AU - Liebig, C.

AU - Mancini, L.

AU - Popovas, A.

AU - Rabus, M.

AU - Rahvar, S.

AU - Scarpetta, G.

AU - Schmidt, R. W.

AU - Snodgrass, C.

AU - Southworth, J.

AU - Starkey, D.

AU - Street, R. A.

AU - Surdej, J.

AU - Wang, X.-B.

AU - Wertz (The Mindstep Consortium), O.

N1 - D.M.B. and K.A.A. acknowledge support from NPRP grant # X-019-1-006 from the Qatar National Research Fund (a member of Qatar Foundation). A.A.F. acknowledges the support from DGAPA-UNAM grant through project IN104612. K.A.A., C.L., M.D., K.H. and M.H. acknowledge grant NPRP-09-476-1-78 from the Qatar National Research Fund (a member of Qatar Foundation). CS has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 268421. S.H.G. and X.B.W. would like to thank the financial support from National Natural Science Foundation of China through grants Nos. 10373023, 10773027 and 11333006. T.H. is supported by a Sapere Aude Starting Grant from The Danish Council for Independent Research. T.C.H. acknowledges support from the Korea Research Council of Fundamental Science & Technology (KRCF) via the KRCF Young Scientist Research Fellowship Programme and for financial support from KASI travel grant number 2013-9-400-00. H.K. acknowledges the support from the European Commission under the Marie Curie IEF Programme in FP7. M.R. acknowledges support from FONDECYT postdoctoral fellowship No. 3120097. O.W. (FNRS research fellow) and J. Surdej acknowledge support from the Communauté francaise de Belgique - Actions de recherche concertées – Académie Wallonie-Europe. Date of Acceptance: 31/10/2014

PY - 2015/1

Y1 - 2015/1

N2 - Aims. In this paper, we present the analysis of time-series observations from 2013 and 2014 of five metal-rich ([Fe/H] > −1) globular clusters: NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652. The data have been used to perform a census of the variable stars in the central parts of these clusters.Methods. The observations were made with the electron-multiplying charge-couple device (EMCCD) camera at the Danish 1.54 m Telescope at La Silla, Chile, and they were analysed using difference image analysis to obtain high-precision light curves of the variable stars.Results. It was possible to identify and classify all of the previously known or suspected variable stars in the central regions of the five clusters. Furthermore, we were able to identify and, in most cases, classify 48, 49, 7, 8, and 2 previously unknown variables in NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652, respectively. Especially interesting is the case of NGC 6441, for which the variable star population of about 150 stars has been thoroughly examined by previous studies, including a Hubble Space Telescope study. In this paper we are able to present 49 new variable stars for this cluster, of which one (possibly two) are RR Lyrae stars, two are W Virginis stars, and the rest are long-period semi-regular or irregular variables on the red giant branch. We have also detected the first double-mode RR Lyrae in the cluster.

AB - Aims. In this paper, we present the analysis of time-series observations from 2013 and 2014 of five metal-rich ([Fe/H] > −1) globular clusters: NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652. The data have been used to perform a census of the variable stars in the central parts of these clusters.Methods. The observations were made with the electron-multiplying charge-couple device (EMCCD) camera at the Danish 1.54 m Telescope at La Silla, Chile, and they were analysed using difference image analysis to obtain high-precision light curves of the variable stars.Results. It was possible to identify and classify all of the previously known or suspected variable stars in the central regions of the five clusters. Furthermore, we were able to identify and, in most cases, classify 48, 49, 7, 8, and 2 previously unknown variables in NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652, respectively. Especially interesting is the case of NGC 6441, for which the variable star population of about 150 stars has been thoroughly examined by previous studies, including a Hubble Space Telescope study. In this paper we are able to present 49 new variable stars for this cluster, of which one (possibly two) are RR Lyrae stars, two are W Virginis stars, and the rest are long-period semi-regular or irregular variables on the red giant branch. We have also detected the first double-mode RR Lyrae in the cluster.

KW - Globular clusters: individual:

KW - Stars: variables: RR Lyrae

KW - Stars: variables: general

KW - Instrumentation: high angular resolution

UR - http://adsabs.harvard.edu/abs/2015A%26A...573A.103S

U2 - 10.1051/0004-6361/201424967

DO - 10.1051/0004-6361/201424967

M3 - Article

SN - 0004-6361

VL - 573

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

ER -

Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations

Abstract

Keywords

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Astronomy at St Andrews 2015-2018: Astronomy at St Andrews 2015-2018

Planet population statistics: Planet population statistics from fully-deterministic microlensing campaigns

Wide Area Search for Planets: Project support for the Wide Area Search for Planets

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Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations

Abstract

Keywords

Access to Document

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Projects

Astronomy at St Andrews 2015-2018: Astronomy at St Andrews 2015-2018

Planet population statistics: Planet population statistics from fully-deterministic microlensing campaigns

Wide Area Search for Planets: Project support for the Wide Area Search for Planets

Cite this