Deep imaging of Virgo Z : not a nearby ultrafaint dwarf galaxy, but a distant compact group of galaxies

Context. The search for Milky Way faint satellite galaxies and star clusters has been intensified in recent years thanks to the Sloan Digital Sky Survey (SDSS), and other efforts to verify candidate objects. Aims. We observed the Milky Way satellite candidate Vir Z, reported by Walsh et al. (2009, A...

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Detalles Bibliográficos
Autores: Barbuy, Beatriz, Bica, Eduardo Luiz Damiani, Ortolani, Sergio, Souza, André Lopes de
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2013
País:Brasil
Institución:Universidade Federal do Rio Grande do Sul (UFRGS)
Repositorio:Repositório Institucional da UFRGS
Idioma:inglés
OAI Identifier:oai:www.lume.ufrgs.br:10183/109478
Acceso en línea:http://hdl.handle.net/10183/109478
Access Level:acceso abierto
Palabra clave:Aglomerados de galaxias
Galaxia
Galaxy: general
Galaxies: groups: individual: Virgo Z
Descripción
Sumario:Context. The search for Milky Way faint satellite galaxies and star clusters has been intensified in recent years thanks to the Sloan Digital Sky Survey (SDSS), and other efforts to verify candidate objects. Aims. We observed the Milky Way satellite candidate Vir Z, reported by Walsh et al. (2009, AJ, 137, 450), from the detection of an overdensity in the SDSS database. Methods. Deep subarcsec seeing images from the New Technology Telescope (NTT) and Galileo telescopes were obtained in order to infer the nature of the proposed overdensity. Results. The image and colour-magnitude diagram of the Vir Z field shows no dwarf galaxy. Instead, we identified a compact group of galaxies near the center of the Vir Z field at redshift z ≈ 0.3 ± 0.2, based on the apparent magnitudes of the brightest galaxies assuming L = L∗, and on angular sizes of the spirals assuming physical sizes equal to M31.