The Astrophysical Journal, 882:169 (18pp), 2019 September 10 https://doi.org/10.3847/1538-4357/ab3977 © 2019. The American Astronomical Society. All rights reserved. On the Use of Field RR Lyrae as Galactic Probes. I. The Oosterhoff Dichotomy Based on Fundamental Variables* M. Fabrizio1,2 , G. Bono1,3 , V. F. Braga4,5 , D. Magurno1,3 , S. Marinoni1,2, P. M. Marrese1,2, I. Ferraro1, G. Fiorentino6 , G. Giuffrida1, G. Iannicola1, M. Monelli7,8 , G. Altavilla1,2, B. Chaboyer9 , M. Dall’Ora10 , C. K. Gilligan9, A. Layden11 , M. Marengo12 , M. Nonino13, G. W. Preston14, B. Sesar15 , C. Sneden16 , E. Valenti17 , F. Thévenin18, and E. Zoccali4,19 1 INAF–Osservatorio Astronomico di Roma, Via Frascati 33, I-00078, Monte Porzio Catone (Roma), Italy;
[email protected] 2 Space Science Data Center–ASI, Via del Politecnico s.n.c., I-00133 Roma, Italy 3 Department of Physics, Universitá di Roma Tor Vergata, via della Ricerca Scientifica 1, I-00133 Roma, Italy 4 Instituto Milenio de Astrofísica, Santiago, Chile 5 Departamento de Física, Facultad de Ciencias Exactas, Universidad Andrés Bello, Fernández Concha 700, Las Condes, Santiago, Chile 6 INAF–Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, I-40129, Bologna, Italy 7 Instituto de Astrofísica de Canarias, Calle Via Lactea s/n, E-38200 La Laguna, Tenerife, Spain 8 Departamento de Astrofísica, Universidad de La Laguna, E-38200 La Laguna, Tenerife, Spain 9 Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755, USA 10 INAF–Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli, Italy 11 Bowling Green State University, Bowling Green, OH 43403, USA 12 Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA 13 INAF–Osservatorio Astronomico di Trieste, Via G.B.