The First Galaxy Cluster Discovered by the VISTA Variables in the Vía Láctea Survey
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Fecha
2019-03-20
Profesor/a Guía
Facultad/escuela
Idioma
en
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Editor
Astrophysical Journal
Nombre de Curso
Licencia CC
Atribución 4.0 Internacional (CC BY 4.0)
Licencia CC
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
We report the first confirmed detection of the galaxy cluster VVV-J144321-611754 at very low latitudes (l = 315.°836, b = -1.°650) located in the tile d015 of the VISTA Variables in the Vía Láctea (VVV) survey. We defined the region of 30 ×30 arcmin 2 centered in the brightest galaxy finding 25 galaxies. For these objects, extinction-corrected median colors of (H-K s ) = 0.34 ± 0.05 mag, (J-H) = 0.57 ± 0.08 mag, and (J-K s ) = 0.87 ± 0.06 mag; R 1/2 = 1.59 ± 0.″16; C = 3.01 ± 0.08; and Sérsic index n = 4.63 ± 0.39 were estimated. They were visually confirmed showing characteristics of early-type galaxies in the near-IR images. An automatic clustering analysis performed in the whole tile found that the concentration of galaxies VVV-J144321-611754 is a real, compact concentration of early-type galaxies. Assuming a typical galaxy cluster with low X-ray luminosity, the photometric redshift of the brightest galaxy is z = 0.196 ± 0.025. Follow-up near-IR spectroscopy with FLAMINGOS-2 at the Gemini-South telescope revealed that the two brighter cluster galaxies have typical spectra of early-type galaxies and the estimated redshift for the brightest galaxy VVV-J144321.06-611753.9 is z = 0.234 ± 0.022 and that for VVV-J144319.02-611746.1 is z = 0.232 ± 0.019. Finally, these galaxies clearly follow the cluster red sequence in the rest-frame near-IR color-magnitude diagram with a slope similar to a galaxy cluster at a redshift of 0.2. These results are consistent with the presence of a bona fide galaxy cluster beyond the Milky Way disk.
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Indexación Scopus
Palabras clave
galaxies: clusters: general, infrared: galaxies, surveys
Citación
Astrophysical Journal Volume 874, Issue 1 20 March 2019 Article number 46
DOI
10.3847/1538-4357/aaff64