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Title: Photometric and structural properties of NGC 6544: A combined VVV-Hubble space telescope study

We combine archival Hubble Space Telescope imaging with wide-field near-infrared photometry to study the neglected metal-poor Galactic globular cluster NGC 6544. A high spatial resolution map of differential reddening over the inner portion of the cluster is constructed, revealing variations of up to half of the total reddening, and the resulting corrected color-magnitude diagrams reveal a sparse blue horizontal branch and centrally concentrated blue straggler population, verified via relative proper motions. Using the corrected photometry to investigate the cluster distance, reddening, and age via direct comparison to well-calibrated photometry of clusters with similar metallicities, we estimate (m – M){sub 0} = 11.96, E(B – V) = 0.79, and an age coeval with M13 to within the relevant uncertainties. Although our data are insufficient to place tight constraints on the reddening law toward NGC 6544, we find no strong evidence that it is non-standard at optical or near-infrared wavelengths. We also provide near-infrared fiducial sequences extending nearly 2 mag below the cluster main sequence turnoff, generated from a statistically decontaminated sample of cluster stars. Lastly, we redetermine the cluster center and construct a radial number density profile which is well fit by an atypically flat power law with a slope ofmore » about 1.7. We discuss this result, together with a flattened main sequence luminosity function and inverted mass function, in the context of mass segregation and tidal stripping via interactions with Milky Way potential.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4]
  1. Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción (Chile)
  2. Instituto de Astronomía, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile)
  3. Research School of Astronomy and Astrophysics, The Australian National University, Canberra ACT 2611 (Australia)
  4. Departamento de Astronomia, Universidade Federal de Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre 91501-970, RS (Brazil)
Publication Date:
OSTI Identifier:
22342295
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 148; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COLOR; DENSITY; EVOLUTION; INTERACTIONS; LIMITING VALUES; LUMINOSITY; MAPS; MASS; METALLICITY; METALS; MILKY WAY; PHOTOMETRY; PROPER MOTION; SEGREGATION; SPACE; SPATIAL RESOLUTION; STAR CLUSTERS; STARS; STRIPPING; TELESCOPES