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Near-Field Cosmology with RR Lyrae Variable Stars: A First View of Substructure in the Southern Sky

Published online by Cambridge University Press:  09 May 2016

C. Navarrete ,
S. Duffau ,
A. K. Vivas ,
M. Catelan ,
G. Hajdu ,
G. Torrealba ,
C. Cortés ,
V. Belokurov ,
S. Koposov  and
A. J. Drake
C. Navarrete
Affiliation:
Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile email: cnavarre@astro.puc.cl, sduffau@astro.puc.cl Millennium Institute of Astrophysics, Santiago, Chile
S. Duffau
Affiliation:
Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile email: cnavarre@astro.puc.cl, sduffau@astro.puc.cl Millennium Institute of Astrophysics, Santiago, Chile
A. K. Vivas
Affiliation:
Cerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile
M. Catelan
Affiliation:
Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile email: cnavarre@astro.puc.cl, sduffau@astro.puc.cl Millennium Institute of Astrophysics, Santiago, Chile
G. Hajdu
Affiliation:
Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile email: cnavarre@astro.puc.cl, sduffau@astro.puc.cl Millennium Institute of Astrophysics, Santiago, Chile
G. Torrealba
Affiliation:
Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
C. Cortés
Affiliation:
Millennium Institute of Astrophysics, Santiago, Chile Departamento de Física, Facultad de Ciencias Básicas, Universidad Metropolitana de Ciencias de la Educación, Av. José Pedro Alessandri 774, 776-0197 Ñuñoa, Santiago, Chile
V. Belokurov
Affiliation:
Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
S. Koposov
Affiliation:
Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
A. J. Drake
Affiliation:
California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91225, USA
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Abstract

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We present the current status of the spectroscopic follow-up of a large number of RR Lyrae (RRL) halo overdensity candidates recently found by Torrealba et al. (2015) using southern-hemisphere data from the Catalina Real-time Transient Survey (CRTS). Characterizing the individual RRL stars in these overdensities is crucial to confirm them as real halo substructures. Low-resolution spectra have been obtained for RRL stars in 11 different overdensities, using the SOAR and Magellan telescopes. Radial velocities and metallicities have been derived so far for 123 and 99 RRL stars, respectively.

Keywords

Galaxy: haloGalaxy: structurestars: variables: RR Lyrae

References

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