Abstract
We present a search for RR Lyrae stars using the full six-year data set from the Dark Energy Survey covering similar to 5000 deg(2) 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 similar to 335 kpc, and we estimate that our sample is >70% complete at similar to 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(-0.9)(+1.1) kpc with an inner slope of n(1) = - 2.54(-0.09)(+0.09) and an outer slope of n(2) = -5.42(-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 (r(h) greater than or similar to 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 similar to 5 deg. The third is close in projection to the globular cluster NGC 1851 but is similar to 10 kpc more distant and appears to differ in proper motion.
Item Type: | Journal article |
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Faculties: | Physics |
Subjects: | 500 Science > 530 Physics |
ISSN: | 0004-637X |
Language: | English |
Item ID: | 102394 |
Date Deposited: | 05. Jun 2023, 15:40 |
Last Modified: | 05. Jun 2023, 15:40 |