A DECam view of Crater II - Variable stars

DOI

Time series observations of a single dithered field centred on the diffuse dwarf satellite galaxy Crater II were obtained with the Dark Energy Camera (DECam) at the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile, uniformly covering up to two half-light radii. Analysis of the g and i time series results in the identification and characterization of 130 periodic variable stars, including 98 RR Lyrae stars, 7 anomalous Cepheids, and 1 SX Phoenicis star belonging to the Crater II population, and 24 foreground variables of different types. Using the large number of ab-type RR Lyrae stars present in the galaxy, we obtained a distance modulus to Crater II of (m-M)0=20.333+/-0.004 (stat) +/-0.07 (sys). The distribution of the RR Lyrae stars suggests an elliptical shape for Crater II, with an ellipticity of 0.24 and a position angle of 153{deg}. From the RR Lyrae stars, we infer a small metallicity dispersion for the old population of Crater II of only 0.17dex. There are hints that the most metal-poor stars in that narrow distribution have a wider distribution across the galaxy, while the slightly more metal-rich part of the population is more centrally concentrated. Given the features in the colour-magnitude diagram of Crater II, the anomalous Cepheids in this galaxy must have formed through a binary evolution channel of an old population.

Cone search capability for table J/MNRAS/492/1061/table1 (Periodic variable stars in Crater II)

Identifier
DOI http://doi.org/10.26093/cds/vizier.74921061
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/MNRAS/492/1061
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/492/1061
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/492/1061
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/MNRAS/492/1061
Provenance
Creator Vivas A.K.; Walker A.R.; Martinez-Vazquez C.E.; Monelli M.; Bono G.,Dorta A.; Nidever D.L.; Fiorentino G.; Gallart C.; Andreuzzi G.,Braga V.F.; Dall'Ora M.; Olsen K.; Stetson P.B.
Publisher CDS
Publication Year 2023
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Galactic and extragalactic Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy