RR Lyrae Stars in the Newly Discovered Ultra-faint Dwarf Galaxy Centaurus I*
| العنوان: | RR Lyrae Stars in the Newly Discovered Ultra-faint Dwarf Galaxy Centaurus I* |
|---|---|
| المؤلفون: | Martínez-Vázquez, C. E., Cerny, W., Vivas, A. K., Drlica-Wagner, A., Pace, A. B., Simon, J. D., Muñoz, R. R., Walker, A. R., Allam, S., Tucker, D. L., Adamów, M., Carlin, J. L., Choi, Y., Ferguson, P. S., Ji, A. P., Kuropatkin, N., Li, T. S., Martínez-Delgado, David, Mau, S., Mutlu-Pakdil, B., Nidever, D. L., Riley, A. H., Sakowska, J. D., Sand, D. J., Stringfellow, G. S., DELVE Collaboration |
| المساهمون: | National Aeronautics and Space Administration (US), Ministerio de Economía y Competitividad (España) |
| المصدر: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| بيانات النشر: | IOP Publishing, 2021. |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | Physics, Milky Way, FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, RR Lyrae variable, Astrophysics - Astrophysics of Galaxies, Galaxy, Galactic halo, Stars, Distance modulus, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Solar and Stellar Astrophysics (astro-ph.SR), Dwarf galaxy |
| الوصف: | 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 (r h ) of Cen I, while the RRab star (CenI-V3) is at ∼6 r h . 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 μ 0 = 20.354 0.002 mag (σ = 0.03 mag), a heliocentric distance of D o˙ = 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 (f cd) in UFD and classical dwarf galaxies. The full sample of MW dwarf galaxies gives a mean of f cd = 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 (f cd ∼ 0.3). Therefore, there is no evidence for a different fraction of RRcd stars in UFD and classical dwarf galaxies. © 2021. The American Astronomical Society. All rights reserved. The DELVE project is partially supported by Fermilab LDRD project L2019-011 and the NASA Fermi Guest Investigator Program Cycle 9 No. 91201. This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internships (SULI) program. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaboration. Funding for the DES Projects has been provided by the US Department of Energy, the US National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute for Cosmological Physics at the University of Chicago, Center for Cosmology and Astro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência, Tecnologia e Inovação, the Deutsche Forschungsgemeinschaft, and the Collaborating Institutions in the Dark Energy Survey. The Collaborating Institutions are Argonne National Laboratory, the University of California at Santa Cruz, the University of Cambridge, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas-Madrid, the University of Chicago, University College London, the DES-Brazil Consortium, the University of Edinburgh, the Eidgenössische Technische Hochschule (ETH) Zürich, Fermi National Accelerator Laboratory, the University of Illinois at Urbana-Champaign, the Institut de Ciències de l'Espai (IEEC/CSIC), the Institut de Física d'Altes Energies, Lawrence Berkeley National Laboratory, the Ludwig-Maximilians Universität München and the associated Excellence Cluster Universe, the University of Michigan, NSF's NOIRLab, the University of Nottingham, the Ohio State University, the OzDES Membership Consortium, the University of Pennsylvania, the University of Portsmouth, SLAC National Accelerator Laboratory, Stanford University, the University of Sussex, and Texas A&M University. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaiaTest), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortiumTest). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. |
| اللغة: | English |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5b82630c89953360ec9f095e8256c722Test http://hdl.handle.net/10261/264146Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....5b82630c89953360ec9f095e8256c722 |
| قاعدة البيانات: | OpenAIRE |
| الوصف غير متاح. |