RR lyrae stars in the newly discovered ultra-faint dwarf galaxy centaurus I
Author
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Martínez Vázquez, C. E.
Author
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Cerny, W.
Author
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Vivas, A. K.
Author
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Drlica Wagner, A.
Author
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Pace, A. B.
Author
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Simon, J. D.
Author
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Muñoz, R. R.
Author
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Walker, A. R.
Author
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Allam, S.
Author
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Tucker, D. L.
Author
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Adamow, M.
Author
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Carlin, J. L.
Author
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Choi, Y.
Author
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Ferguson, P. S.
Author
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Ji, A. P.
Author
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Kuropatkin, N.
Author
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Li, T. S.
Author
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Martínez Delgado, D.
Author
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Mau, S.
Author
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Mutlu Pakdil, B.
Author
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Nidever, D. L.
Author
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Riley, A. H.
Author
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Sakowska, J. D.
Author
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Sand, D. J.
Author
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Stringfellow, G. S.
Admission date
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2022-05-04T15:59:16Z
Available date
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2022-05-04T15:59:16Z
Publication date
dc.date.issued
2021
Cita de ítem
dc.identifier.citation
The Astronomical Journal, 162:253 (10pp), 2021 December
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Identifier
dc.identifier.other
10.3847/1538-3881/ac2368
Identifier
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https://repositorio.uchile.cl/handle/2250/185257
Abstract
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We report the detection of three RR Lyrae (RRL) stars (two RRc and one RRab) in the ultra-faint dwarf (UFD) galaxy
Centaurus I (Cen I) and two Milky Way (MW) δ Scuti/SX Phoenicis stars based on multi-epoch giz DECam
observations. The two RRc stars are located within two times the half-light radius (rh) of Cen I, while the RRab star
(CenI-V3) is at ∼6 rh. The presence of three distant RRL stars clustered this tightly in space represents a 4.7σ excess
relative to the smooth distribution of RRL in the Galactic halo. Using the newly detected RRL stars, we obtain
a distance modulus to Cen I of μ0 = 20.354 ± 0.002 mag (σ = 0.03 mag), a heliocentric distance of
De = 117.7 ± 0.1 kpc (σ = 1.6 kpc), with systematic errors of 0.07 mag and 4 kpc. The location of the Cen I RRL
stars in the Bailey diagram is in agreement with other UFD galaxies (mainly Oosterhoff II). Finally, we study the
relative rate of RRc+RRd (RRcd) stars (fcd) in UFD and classical dwarf galaxies. The full sample of MW dwarf
galaxies gives a mean of fcd = 0.28. While several UFD galaxies, such as Cen I, present higher RRcd ratios, if we
combine the RRL populations of all UFD galaxies, the RRcd ratio is similar to the one obtained for the classical dwarfs
(fcd ∼ 0.3). Therefore, there is no evidence for a different fraction of RRcd stars in UFD and classical dwarf galaxies.
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Patrocinador
dc.description.sponsorship
Fermilab LDRD project L2019-011
NASA Fermi Guest Investigator Program Cycle 9 91201
United States Department of Energy (DOE)
National Science Foundation (NSF)
Spanish Government
UK Research & Innovation (UKRI)
Science & Technology Facilities Council (STFC)
UK Research & Innovation (UKRI)
Higher Education Funding Council for England (HEFCE)
National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign
University of Chicago
Ohio State University
Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University
Financiadora de Inovacao e Pesquisa (Finep)
Fundaco Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro
Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ)
Spanish Government
German Research Foundation (DFG)
Dark Energy Survey
United States Department of Energy (DOE)
University of California at Santa Cruz
University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid
University of Chicago, University College London
DES-Brazil Consortium
University of Edinburgh
ETH Zurich
United States Department of Energy (DOE)
University of Chicago
University of Illinois at Urbana-Champaign
Institut de Ciencies de l'Espai (IEEC/CSIC)
Institut de Fisica d'Altes Energies, Lawrence Berkeley National Laboratory
Ludwig-Maximilians Universitat Munchen
associated Excellence Cluster Universe
University of Michigan, NSF's NOIRLab
University of Nottingham
Ohio State University
OzDES Membership Consortium
University of Pennsylvania
University of Portsmouth
Stanford University
United States Department of Energy (DOE)
Stanford University
University of Sussex
Texas AM University
United States Department of Energy (DOE) DE-AC02-07CH11359
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Lenguage
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en
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Publisher
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IOP
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Type of license
dc.rights
Attribution-NonCommercial-NoDerivs 3.0 United States