The structural properties and star formation history of Leo T from deep LBT photometry

被引：75

作者：

De Jong, J. T. A. ^{[1
]}

Harris, J. ^{[2
]}

Coleman, M. G. ^{[1
]}

Martin, N. F. ^{[1
]}

Bell, E. F. ^{[1
]}

Rix, H. -W. ^{[1
]}

Hill, J. M. ^{[3
]}

Skillman, E. D. ^{[4
]}

Sand, D. J. ^{[2
]}

Olszewski, E. W. ^{[2
]}

Zaritsky, D. ^{[2
]}

Thompson, D. ^{[3
]}

Giallongo, E. ^{[5
]}

Ragazzoni, R. ^{[6
]}

DiPaola, A. ^{[5
]}

Farinato, J. ^{[6
]}

Testa, V. ^{[5
]}

Bechtold, J. ^{[2
]}

机构：

[1] Max Planck Inst Astron, D-69117 Heidelberg, Germany

[2] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA

[3] Univ Arizona, Large Binocular Telescope Observ, Tucson, AZ 85721 USA

[4] Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA

[5] Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, Italy

[6] Osserv Astron Padova, INAF, I-35122 Padua, Italy

来源：

ASTROPHYSICAL JOURNAL | 2008年 / 680卷 / 02期

关键词：

galaxies : individual (Leo T dSph); galaxies : stellar content; Local Group;

D O I：

10.1086/587835

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present deep, wide-field g and r photometry of the transition-type dwarf galaxy Leo T, obtained with the blue arm of the Large Binocular Telescope. The data confirm the presence of both very young (< 1 Gyr) and much older (> 5 Gyr) stars. We study the structural properties of the old and young stellar populations by preferentially selecting either population on the basis of their color and magnitude. The young population is significantly more concentrated than the old population, with half-light radii of 104 +/- 8 and 148 +/- 16 pc, respectively, and their centers are slightly offset. Approximately 10% of the total stellar mass is estimated to be represented by the young stellar population. Comparison of the color-magnitude diagram(CMD) with theoretical isochrones, as well as numerical CMD fitting, suggests that star formation began over 10 Gyr ago and continued in recent times until at least a few hundred Myr ago. The CMD-fitting results are indicative of two distinct star formation bursts, with a quiescent period around 3 Gyr ago, albeit at low significance. The results are consistent with no metallicity evolution and a value of [Fe/H] similar to -1.5 over the entire age of the system. Finally, the data show little, if any, sign of tidal distortion of Leo T.

引用

页码：1112 / 1119

页数：8

共 41 条

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