High-cadence stellar variability studies of RR Lyrae stars with DECam: New multi-band templates

TL;DR

This paper presents an extensive set of high-quality, multi-band RR Lyrae light curve templates derived from DECam observations, useful for distance measurements and classification in large surveys like LSST.

Contribution

It introduces a new, detailed set of RR Lyrae templates in griz bands, including a novel method for handling photometric outliers, and analyzes their Fourier parameters and light curve descriptors.

Findings

136 RRab and 144 RRc templates publicly available

Fourier parameters correlate with pulsation mode, period, and wavelength

New approach to outlier correction in light curve template construction

Abstract

We present the most extensive set to date of high-quality RR Lyrae light curve templates in the griz bands, based on time-series observations of the Dark Energy Camera Plane Survey (DECaPS) East field, located in the Galactic bulge at coordinates (RA, DEC)(J2000) = (18:03:34, -29:32:02), obtained with the Dark Energy Camera (DECam) on the 4-m Blanco telescope at the Cerro Tololo Inter-American Observatory (CTIO). Our templates, which cover both fundamental-mode (RRab) and first-overtone (RRc) pulsators, can be especially useful when there is insufficient data for accurately calculating the average magnitudes and colors, hence distances, as well as to inform multi-band light curve classifiers, as will be required in the case of the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST). In this paper, we describe in detail the procedures that were adopted in producing these templates, including a novel approach to account for the presence of outliers in photometry. Our final sample comprises 136 RRab and 144 RRc templates, all of which are publicly available. Lastly, in this paper we study the inferred Fourier parameters and other light curve descriptors, including rise time,skewness, and kurtosis, as well as their correlations with the pulsation mode, period, and effective wavelength.