INVESTIGADORES
BARAVALLE Laura Daniela
artículos
Título:
The First Galaxy Cluster Discovered by the VISTA Variables in the Vía Láctea Survey
Autor/es:
BARAVALLE, L. D.; CASTELLÓN, J. L. NILO; ALONSO, M. V.; TELLO, J. DÍAZ; DAMKE, G.; VALOTTO, C.; LARENAS, H. CUEVAS; SÁNCHEZ, B.; RÍOS, M. DE LOS; MINNITI, D.; DOMÍNGUEZ, M.; GUROVICH, S.; BARBÁ, R.; SOTO, M.; CASTRO, F. MILLA
Revista:
The Astrophysical Journal
Editorial:
AAS JOURNAL
Referencias:
Lugar: Washington; Año: 2019 vol. 874
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 arcmin2 centered in the brightest galaxy finding 25 galaxies. For these objects, extinction-corrected median colors of (H−Ks)=0.34±0.05 mag, (J−H)=0.57±0.08 mag, and (J−Ks)=0.87±0.06 mag; R1/2=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.