Identifying RR Lyrae Variable Stars in Six Years of the Dark Energy Survey
Creators: name: Stringer, K. M.
name: Drlica-Wagner, A.
name: Macri, L.
name: Martínez-Vázquez, C. E.
name: Vivas, A. K.
name: Ferguson, P.
name: Pace, A. B.
name: Walker, A. R.
name: Neilsen, E.
name: Tavangar, K.
name: Wester, W.
name: Abbott, T. M. C.
name: Aguena, M.
name: Allam, S.
name: Bacon, D.
name: Bechtol, K.
name: Bertin, E.
name: Brooks, D.
name: Burke, D. L.
name: Rosell, A. Carnero
name: Kind, M. Carrasco
name: Carretero, J.
name: Costanzi, M.
name: Crocce, M.
name: da Costa, L. N.
name: Pereira, M. E. S.
name: De Vicente, J.
name: Desai, S.
name: Diehl, H. T.
name: Doel, P.
name: Ferrero, I.
name: García-Bellido, J.
name: Gaztanaga, E.
name: Gerdes, D. W.
name: Gruen, D.
name: Gruendl, R. A.
name: Gschwend, J.
name: Gutierrez, G.
name: Hinton, S. R.
name: Hollowood, D. L.
name: Honscheid, K.
name: Hoyle, B.
name: James, D. J.
name: Kuehn, K.
name: Kuropatkin, N.
name: Li, T. S.
name: Maia, M. A. G.
name: Marshall, J. L.
name: Menanteau, F.
name: Miquel, R.
name: Morgan, R.
name: Ogando, R. L. C.
name: Palmese, A.
name: Paz-Chinchón, F.
name: Plazas, A. A.
name: Roodman, A.
name: Sanchez, E.
name: Schubnell, M.
name: Serrano, S.
name: Sevilla-Noarbe, I.
name: Smith, M.
name: Soares-Santos, M.
name: Suchyta, E.
name: Tarle, G.
name: Thomas, D.
name: To, C.
name: Varga, T. N.
name: Wilkinson, R. D.
name: Zhang, Y.
name: Collaboration, the DES
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present a search for RR Lyrae stars using the full six-year data set from the Dark Energy Survey (DES) covering ~5,000 sq. deg. of the southern sky. Using a multi-stage multi-variate classification and light curve template-fitting scheme, we identify RR Lyrae candidates with a median of 35 observations per candidate. We detect 6,971 RR Lyrae candidates out to ~335 kpc, and we estimate that our sample is &gt;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 $R_0 = 32.1^{+1.1}_{-0.9}$ kpc with an inner slope of $n_1 = -2.54^{+0.09}_{-0.09}$ and an outer slope of $n_2 = -5.42^{+0.13}_{-0.14}$. 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 ($r_h &gt; 500$ 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 similar distance and proper motion to the ultra-faint 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.
description: 34 pages, 20 figures, 9 tables. Updated to match published version. Data products are available at https://des.ncsa.illinois.edu/releases/other/y6-rrl