A Caltech Library Service

The Palomar Transient Factory and RR Lyrae: The Metallicity–Light Curve Relation Based on ab-type RR Lyrae in the Kepler Field

Ngeow, Chow-Choong and Yu, Po-Chieh and Bellm, Eric and Yang, Ting-Chang and Chang, Chan-Kao and Miller, Adam and Laher, Russ and Surace, Jason and Ip, Wing-Huen (2016) The Palomar Transient Factory and RR Lyrae: The Metallicity–Light Curve Relation Based on ab-type RR Lyrae in the Kepler Field. Astrophysical Journal Supplement Series, 227 (2). Art. No. 30. ISSN 0067-0049.

[img] PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


The wide-field synoptic sky surveys, known as the Palomar Transient Factory (PTF) and the intermediate Palomar Transient Factory (iPTF), will accumulate a large number of known and new RR Lyrae. These RR Lyrae are good tracers to study the substructure of the Galactic halo if their distance, metallicity, and galactocentric velocity can be measured. Candidates of halo RR Lyrae can be identified from their distance and metallicity before requesting spectroscopic observations for confirmation. This is because both quantities can be obtained via their photometric light curves, because the absolute V-band magnitude for RR Lyrae is correlated with metallicity, and the metallicity can be estimated using a metallicity–light curve relation. To fully utilize the PTF and iPTF light-curve data in related future work, it is necessary to derive the metallicity–light curve relation in the native PTF/iPTF R-band photometric system. In this work, we derived such a relation using the known ab-type RR Lyrae located in the Kepler field, and it is found to be [Fe/H]_(PTF) = -4.089-7.346P + 1.280φ_(31) (where P is pulsational period and φ_(31) is one of the Fourier parameters describing the shape of the light curve), with a dispersion of 0.118 dex. We tested our metallicity–light curve relation with new spectroscopic observations of a few RR Lyrae in the Kepler field, as well as several data sets available in the literature. Our tests demonstrated that the derived metallicity–light curve relation could be used to estimate metallicities for the majority of the RR Lyrae, which are in agreement with the published values.

Item Type:Article
Related URLs:
URLURL TypeDescription
Ngeow, Chow-Choong0000-0001-8771-7554
Yu, Po-Chieh0000-0001-8894-0854
Bellm, Eric0000-0001-8018-5348
Chang, Chan-Kao0000-0003-1656-4540
Miller, Adam0000-0001-9515-478X
Laher, Russ0000-0003-2451-5482
Surace, Jason0000-0001-7291-0087
Ip, Wing-Huen0000-0002-3140-5014
Additional Information:© 2016 The American Astronomical Society. Received 2016 August 19; revised 2016 October 11; accepted 2016 October 27; published 2016 December 15. We thank the referee for valuable input that improved the manuscript. We acknowledge Wee Siang Edmund Yuen, a 2015 summer student at the National Central University, for carrying out the preliminary analysis of the PTF data for RR Lyrae in the Kepler field. C.C.N. is thankful for the funding from the Ministry of Science and Technology (Taiwan) under grants 104-2112-M-008-012-MY3 and 104-2119-M-008-024. This research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Facility: PO:1.2m.
Group:Palomar Transient Factory, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Ministry of Science and Technology (Taipei)104-2112-M-008-012-MY3
Ministry of Science and Technology (Taipei)104-2119-M-008-024
Subject Keywords:distance scale – stars: abundances – stars: variables: RR Lyrae
Issue or Number:2
Record Number:CaltechAUTHORS:20161216-091221197
Persistent URL:
Official Citation:Chow-Choong Ngeow et al 2016 ApJS 227 30
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:72887
Deposited By: Tony Diaz
Deposited On:16 Dec 2016 17:25
Last Modified:09 Mar 2020 13:19

Repository Staff Only: item control page