Identifying RR lyrae variable stars in six years of the dark energy survey

K. M. Stringer, A. Drlica-Wagner, L. Macri, C. E. Martínez-Vázquez, A. K. Vivas, P. Ferguson, A. B. Pace, A. R. Walker, E. Neilsen, K. Tavangar, W. Wester, T. M.C. Abbott, M. Aguena, S. Allam, D. Bacon, K. Bechtol, E. Bertin, D. Brooks, D. L. Burke, A. Carnero RosellM. Carrasco Kind, J. Carretero, M. Costanzi, M. Crocce, L. N. Da Costa, M. E.S. Pereira, J. De Vicente, S. Desai, H. T. Diehl, P. Doel, I. Ferrero, J. García-Bellido, E. Gaztanaga, D. W. Gerdes, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, S. R. Hinton, D. L. Hollowood, K. Honscheid, B. Hoyle, D. J. James, K. Kuehn, N. Kuropatkin, T. S. Li, M. A.G. Maia, J. L. Marshall, F. Menanteau, R. Miquel, R. Morgan, R. L.C. Ogando, A. Palmese, F. Paz-Chinchón, A. A. Plazas, A. Roodman, E. Sanchez, M. Schubnell, S. Serrano, I. Sevilla-Noarbe, M. Smith, M. Soares-Santos, E. Suchyta, G. Tarle, D. Thomas, C. To, T. N. Varga, R. D. Wilkinson, Y. Zhang

Research output: Contribution to journalReview articlepeer-review

Abstract

We present a search for RR Lyrae stars using the full six-year data set from the Dark Energy Survey covering ∼5000 deg2 of the southern sky. Using a multistage multivariate classification and light-curve template-fitting scheme, we identify RR Lyrae candidates with a median of 35 observations per candidate. We detect 6971 RR Lyrae candidates out to ∼335 kpc, and we estimate that our sample is >70% complete at ∼150 kpc. We find excellent agreement with other wide-area RR Lyrae catalogs and RR Lyrae studies targeting the Magellanic Clouds and other Milky Way satellite galaxies. We fit the smooth stellar halo density profile using a broken-power-law model with fixed halo flattening (q = 0.7), and we find strong evidence for a break at = - R 32.1+ kpc 0 0.9 1.1 with an inner slope of = - - n 2.54+ 1 0.09 0.09 and an outer slope of = - - n 5.42+ 2 0.14 0.13. We use our catalog to perform a search for Milky Way satellite galaxies with large sizes and low luminosities. Using a set of simulated satellite galaxies, we find that our RR Lyrae-based search is more sensitive than those using resolved stellar populations in the regime of large (rh 500 pc), low-surface-brightness dwarf galaxies. A blind search for large, diffuse satellites yields three candidate substructures. The first can be confidently associated with the dwarf galaxy Eridanus II. The second has a distance and proper motion similar to the ultrafaint dwarf galaxy Tucana II but is separated by ∼5 deg. The third is close in projection to the globular cluster NGC 1851 but is ∼10 kpc more distant and appears to differ in proper motion.

Original languageEnglish (US)
Article numberabe873
JournalAstrophysical Journal
Volume911
Issue number2
DOIs
StatePublished - Apr 20 2021
Externally publishedYes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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