共 21 条
Deep imaging of Virgo Z: not a nearby ultrafaint dwarf galaxy, but a distant compact group of galaxies
被引:2
作者:
Barbuy, B.
[1
]
Bica, E.
[2
]
Ortolani, S.
[3
]
Lopes-Souza, A.
[1
]
机构:
[1] Univ Sao Paulo, IAG, BR-05508900 Sao Paulo, Brazil
[2] Univ Fed Rio Grande do Sul, Dept Astron, BR-91501970 Porto Alegre, RS, Brazil
[3] Univ Padua, Dipartimento Fis & Astron Galileo Galilei, I-35122 Padua, Italy
基金:
巴西圣保罗研究基金会;
关键词:
Galaxy: general;
galaxies: groups: individual: Virgo Z;
PHOTOMETRIC STANDARD STARS;
MILKY-WAY;
LUMINOSITY FUNCTION;
CELESTIAL EQUATOR;
SKY SURVEY;
DISCOVERY;
EVOLUTION;
CLUSTER;
D O I:
10.1051/0004-6361/201321943
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
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 approximate to 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 M 31.
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