Year: 2017
Type: article
Abstract: Multi-wavelength CCD photometry over 21 years has been used to produce deep color–magnitude diagrams (CMDs) together with light curves for the variables in the Galactic globular cluster NGC 5824. Twenty-one new cluster RR Lyrae stars are identified, bringing the total to 47, of which 42 have reliable periods determined for the first time. The CMD is matched using BaSTI isochrones with ages of 13 Gyr, and reddening is found to be using the period–Wesenheit relation in two colors, the distance modulus is corresponding to a distance of 30.9 Kpc. The observations show no signs of populations that are significantly younger than the 13 Gyr stars. The width of the red giant branch does not allow for a spread in greater than , and there is no photometric evidence for widened or parallel sequences. The pseudo-CMD shows a bifurcation of the red giant branch that by analogy with other clusters is interpreted as being due to differing spectral signatures of the first (75%) and second (25%) generations of stars whose age difference is close enough that main-sequence (MS) turnoffs in the CMD are unresolved. The cluster MS is visible against the background out to a radial distance of ∼17 arcmin. We conclude that NGC 5824 appears to be a classical Oosterhoff Type II globular cluster, without overt signs of being a remnant of a now-disrupted dwarf galaxy.
Source: The Astronomical Journal
Authors: A. R. Walker, G. Andreuzzi, C. E. Martínez-Vázquez, A. M. Kunder, P. B. Stetson, S. Cassisi, M. Monelli, G. Bono, M Dall’Ora, A. K. Vivas
Institutions: Cerro Tololo Inter-American Observatory, Telescopio Nazionale Galileo, Universidad de La Laguna, Instituto de Astrofísica de Canarias, Saint Martin's University, Leibniz Institute for Astrophysics Potsdam, Herzberg Institute of Astrophysics, Dominion Astrophysical Observatory, Collurania Teramo Observatory, University of Rome Tor Vergata, Astronomical Observatory of Capodimonte
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, U.S. Department of Energy, University of Pennsylvania, Ohio State University, University of Chicago, University of Portsmouth, University College London, University of Sussex, Deutsche Forschungsgemeinschaft, Ministerio de Economía y Competitividad, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Financiadora de Estudos e Projetos, Institut de Física d'Altes Energies, University of Illinois at Urbana-Champaign, Canadian Space Agency, Science and Technology Facilities Council, Integrated Electronics Engineering Center, Binghamton University, Argonne National Laboratory, Fermilab, Lawrence Berkeley National Laboratory, SLAC National Accelerator Laboratory
OpenAlex ID: W2614172715