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Zwicky Transient Facility and Globular Clusters: the Period–Luminosity and Period–Luminosity–Color Relations for Late-type Contact Binaries

Ngeow, Chow-Choong and Liao, Szu-Han and Bellm, Eric C. and Duev, Dmitry A. and Graham, Matthew J. and Mahabal, Ashish A. and Masci, Frank J. and Medford, Michael S. and Riddl, Reed and Rusholme, Ben (2021) Zwicky Transient Facility and Globular Clusters: the Period–Luminosity and Period–Luminosity–Color Relations for Late-type Contact Binaries. Astronomical Journal, 162 (2). Art. No. 63. ISSN 0004-6256. doi:10.3847/1538-3881/ac01ea.

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In this work, we aimed to derive the gri-band period–luminosity (PL) and period–luminosity–color (PLC) relations for late-type contact binaries, for the first time, located in globular clusters, using the homogeneous light curves collected by the Zwicky Transient Factory (ZTF). We started with 79 contact binaries in 15 globular clusters, and retained 30 contact binaries in 10 globular clusters that have adequate numbers of data points in the ZTF light curves and are unaffected by blending. Magnitudes at mean and maximum light of these contact binaries were determined using a fourth-order Fourier expansion, while extinction corrections were done using the Bayerstar2019 3D reddening map together with adopting the homogeneous distances to their host globular clusters. After removing early-type and "anomaly" contact binaries, our derived gri-band PL and period–Wesenheit (PW) relations exhibited a much larger dispersion with large errors on the fitted coefficients. Nevertheless, the gr-band PL and PW relations based on this small sample of contact binaries in globular clusters were consistent with those based on a larger sample of nearby contact binaries. Good agreements of the PL and PW relations suggested both samples of contact binaries in the local Solar neighborhood and in the distant globular clusters can be combined and used to derive and calibrate the PL, PW, and PLC relations. The final derived gr-band PL, PW, and PLC relations were much improved over those based on the limited sample of contact binaries in the globular clusters.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ngeow, Chow-Choong0000-0001-8771-7554
Bellm, Eric C.0000-0001-8018-5348
Duev, Dmitry A.0000-0001-5060-8733
Graham, Matthew J.0000-0002-3168-0139
Mahabal, Ashish A.0000-0003-2242-0244
Masci, Frank J.0000-0002-8532-9395
Medford, Michael S.0000-0002-7226-0659
Riddl, Reed0000-0002-0387-370X
Rusholme, Ben0000-0001-7648-4142
Additional Information:© 2021. The American Astronomical Society. Received 2021 February 27; revised 2021 May 13; accepted 2021 May 15; published 2021 July 16. We thank the useful discussions and comments from an anonymous referee to improve the manuscript. We thank the funding from Ministry of Science and Technology (Taiwan) under the contract 107-2119-M-008-014-MY2, 107-2119-M-008 012, 108-2628-M-007-005-RSP, and 109-2112-M-008-014-MY3. Based on observations obtained with the Samuel Oschin Telescope 48 inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. Major funding has been provided by the U.S. National Science Foundation under grant No. AST-1440341 and by the ZTF partner institutions: the California Institute of Technology, the Oskar Klein Centre, the Weizmann Institute of Science, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron, the University of Wisconsin-Milwaukee, and the TANGO Program of the University System of Taiwan. This research has made use of the SIMBAD database and the VizieR catalog access tool, operated at CDS, Strasbourg, France. This research made use of Astropy, 17 a community-developed core Python package for Astronomy (Astropy Collaboration et al. 2013, 2018). This research has made use of the SVO Filter Profile Service ( supported from the Spanish MINECO through grant AYA2017-84089. Facility: PO:1.2m. - Software: astropy (Astropy Collaboration et al. 2013, 2018), gatspy (VanderPlas & Ivezić 2015), Matplotlib (Hunter 2007), NumPy (Harris et al. 2020), SciPy (Virtanen et al.2020).
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC), Zwicky Transient Facility
Funding AgencyGrant Number
Ministry of Science and Technology (Taipei)107-2119-M-008-014-MY2
Ministry of Science and Technology (Taipei)107-2119-M-008-012
Ministry of Science and Technology (Taipei)108-2628-M-007-005-RSP
Ministry of Science and Technology (Taipei)109-2112-M-008-014-MY3
ZTF partner institutionsUNSPECIFIED
Ministerio de Economía, Industria y Competitividad (MINECO)AYA2017-84089
Subject Keywords:Contact binary stars; Globular star clusters; Sky surveys; Distance indicators
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Contact binary stars (297); Globular star clusters (656); Sky surveys (1464); Distance indicators (394)
Record Number:CaltechAUTHORS:20210604-142606782
Persistent URL:
Official Citation:Chow-Choong Ngeow et al 2021 AJ 162 63
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109402
Deposited By: George Porter
Deposited On:07 Jun 2021 14:17
Last Modified:16 Nov 2021 19:35

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