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Exploring the crowded central region of ten Galactic globular clusters using EMCCDs Variable star searches and new discoveries

Figuera Jaimes, R. and Calchi Novati, S. (2016) Exploring the crowded central region of ten Galactic globular clusters using EMCCDs Variable star searches and new discoveries. Astronomy and Astrophysics, 588 . Art. No. A128. ISSN 0004-6361. doi:10.1051/0004-6361/201527641.

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Aims. We aim to obtain time-series photometry of the very crowded central regions of Galactic globular clusters; to obtain better angular resolution thanhas been previously achieved with conventional CCDs on ground-based telescopes; and to complete, or improve, the census of the variable star population in those stellar systems. Methods. Images were taken using the Danish 1.54-m Telescope at the ESO observatory at La Silla in Chile. The telescope was equipped with an electron-multiplying CCD, and the short-exposure-time images obtained (ten images per second) were stacked using the shift-and-add technique to produce the normal-exposure-time images (minutes). Photometry was performed via difference image analysis. Automatic detection of variable stars in the field was attempted. Results. The light curves of 12 541 stars in the cores of ten globular clusters were statistically analysed to automatically extract the variable stars. We obtained light curves for 31 previously known variable stars (3 long-period irregular, 2 semi-regular, 20 RR Lyrae, 1 SX Phoenicis, 3 cataclysmic variables, 1 W Ursae Majoris-type and 1 unclassified) and we discovered 30 new variables (16 long-period irregular, 7 semi-regular, 4 RR Lyrae, 1 SX Phoenicis and 2 unclassified). Fluxes and photometric measurements for these stars are available in electronic form through the Strasbourg astronomical Data Center.

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URLURL TypeDescription DOIArticle Paper
Calchi Novati, S.0000-0002-7669-1069
Additional Information:© 2016 ESO. Received 26 October 2015. Accepted 22 December 2015. Our thanks go to Christine Clement for clarifying the known variable star content of each cluster and the numbering systems within each one while we were working on these clusters. This support to the astronomical community is very much appreciated. The Danish 1.54m telescope is operated with a grant from the Danish Natural Science Foundation (FNU). R.F.J. thanks Ian Taylor for sorting out all my computational needs on my arrival at St Andrews. RFJ also thanks Katherine White for her comments and suggestions on the improvement of my English language. This publication was made possible by NPRP grant # X-019-1-006 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. K.H. acknowledges support from STFC grant ST/M001296/1. G.D. acknowledges Regione Campania for support from POR-FSE Campania 2014-2020. T.H. is supported by a Sapere Aude Starting Grant from the Danish Council for Independent Research. Research at Centre for Star and Planet Formation is funded by the Danish National Research Foundation. 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 & 2014-1-400-06. O.W. and J. Surdej acknowledge support from the Communauté française de Belgique – Actions de recherche concertées – Académie Wallonie-Europe. This work has made extensive use of the ADS and SIMBAD services, for which we are thankful.
Funding AgencyGrant Number
Danish Natural Science Foundation (FNU)UNSPECIFIED
Qatar National Research FundX-019-1-006
Science and Technology Facilities Council (STFC)ST/M001296/1
Regione CampaniaPOR-FSE Campania 2014–2020
Danish Council for Independent ResearchUNSPECIFIED
Danish National Research FoundationUNSPECIFIED
Korea Research Council of Fundamental Science & Technology (KRCF) KRCF Young Scientist Research Fellowship ProgrammeUNSPECIFIED
Korea Astronomy and Space Science Institute (KASI)2013-9-400-00
Korea Astronomy and Space Science Institute (KASI)2014-1-400-06
Communauté française de Belgique – Actions de recherche concertées – Académie universitaire Wallonie-EuropeUNSPECIFIED
Subject Keywords:blue stragglers, galaxies: star clusters: general, globular clusters: general, stars: variables: RR Lyrae, novae, cataclysmic variables, instrumentation: high angular resolution
Record Number:CaltechAUTHORS:20160519-131755093
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Official Citation:Exploring the crowded central region of ten Galactic globular clusters using EMCCDs - Variable star searches and new discoveries R. Figuera Jaimes, D. M. Bramich, et al. , J. Skottfelt, N. Kains, U. G. Jørgensen, K. Horne, M. Dominik, K. A. Alsubai, V. Bozza, S. Calchi Novati, S. Ciceri, G. D’Ago, P. Galianni, S.-H. Gu, K. B. W Harpsøe, T. Haugbølle, T. C. Hinse, M. Hundertmark, D. Juncher, H. Korhonen, 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 and O. Wertz A&A, 588 (2016) A128 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:67192
Deposited By: Ruth Sustaita
Deposited On:19 May 2016 21:34
Last Modified:11 Nov 2021 00:28

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