The Globular Cluster M15. I. Identification, Discovery, and Period Determination of Variable Stars

Abstract

We present new $BVI$ CCD photometry for variables in the globular cluster M15. Our photometry was obtained using both the image subtraction package ISIS and DAOPHOT/ALLFRAME. The data were acquired in 2001 on two observing runs on 11 observing nights using the 2-m telescope of the Bulgarian National Astronomical Observatory ``Rozhen'' with a Photometrics CCD camera. For 40 previously known variables, we present a period for the first time, and improved periods were obtained for many previously known variables. Fourteen new variables are reported. We present updated Bailey diagrams for the cluster and discuss its Oosterhoff classification. Although many of M15's RRab pulsators fall at an intermediate locus between Oosterhoff types I and II in the Bailey diagram, we argue that M15 is indeed a bona-fide Oosterhoff type II

arXiv comment48 pages, 7 figures, 3 tables

References in corpus (12)

• A method for optimal image subtraction
• Homogeneous Photometry for Star Clusters and Resolved Galaxies. II. Photometric Standard Stars
• Variable Stars in Galactic Globular Clusters
• A multi-color and Fourier study of RR Lyrae variables in the globular cluster NGC 5272 (M3)
• Variable Stars in the Unusual, Metal-Rich Globular Cluster NGC 6388
• The RR Lyrae Period-Amplitude Relation as a Clue to the Origin of the Oosterhoff Dichotomy
• The Evolutionary Status of M3 RR Lyrae Variables: Breakdown of the Canonical Framework?
• Is There a Difference in Luminosity between Field and Cluster RR Lyrae Variables?
• Deep HST/FOC Imaging of the Central Density Cusp of the Globular Cluster M15
• A Catalog of Helium Abundance Indicators from Globular Cluster Photometry
• The outer-halo globular cluster NGC 6229. IV. Variable stars
• RR Lyrae pulsational temperature scales: On the consistency between different empirical relations

Cited by in corpus (24)

• Gaia Data Release 3: All-sky classification of 12.4 million variable sources into 25 classes
• Characteristics of the Galaxy according to Cepheids
• The ACS LCID Project. I. Short-Period Variables in the Isolated Dwarf Spheroidal Galaxies Cetus & Tucana
• The RR Lyrae variables and Horizontal Branch of NGC6656 (M22)
• La Silla QUEST RR Lyrae Star Survey: Region I
• Gaia Data Release 3: Cross-match of Gaia sources with variable objects from the literature
• The Globular Cluster NGC 5286. II. Variable Stars
• A New Census of the variable star population in the Globular Cluster NGC 2419
• Constraints on the Distance Moduli, Helium and Metal Abundances, and Ages of Globular Clusters from their RR Lyrae and Non-Variable Horizontal-Branch Stars. I. M3, M15, and M92
• New LZ and PW(Z) relations of RR Lyrae stars calibrated with Gaia EDR3 parallaxes
• A Re-Evaluation of the Evolved Stars in the Globular Cluster M13
• Study of Globular Cluster M53: new variables, distance, metallicity
• Zwicky Transient Facility and Globular Clusters: The Period-Luminosity and Period-Wesenheit Relations for Type II Cepheids
• Multi-Periodic Oscillations in Cepheids and RR Lyrae-Type Stars
• The Horizontal Branch of NGC 1851: Constraints from its RR Lyrae Variables
• On the Use of Field RR Lyrae as Galactic Probes. VI. Mixed mode RR Lyrae variables in Fornax and in nearby dwarf galaxies
• The Swift/UVOT Stars Survey. II. RR Lyrae Stars in M 3 and M 15
• Multi-Mode Oscillations in Classical Cepheids and RR Lyrae-Type Stars
• Multiple populations in globular clusters: Unified efforts from stellar evolution and chemical evolution models
• Periods and classifications of RR Lyrae stars in the globular cluster M15
• The temperature distribution of horizontal branch stars: methods and first results
• Gaia Data Release 2: Specific characterisation and validation of all-sky Cepheids and RR Lyrae stars
• BVI Photometry and the Red Giant Branch Luminosity Function of M15
• Optical and near-infrared pulsation properties of RR Lyrae and Population II Cepheid variables in the Messier 15 globular cluster