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

J. T.A. De Jong; J. Harris; M. G. Coleman; N. F. Martin; E. F. Bell; H. W. Rix; J. M. Hill; E. D. Skillman; D. J. Sand; E. W. Olszewski; D. Zaritsky; D. Thompson; E. Giallongo; R. Ragazzoni; A. DiPaola; J. Farinato; V. Testa; J. Bechtold

doi:10.1086/587835

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

J. T.A. De Jong, J. Harris, M. G. Coleman, N. F. Martin, E. F. Bell, H. W. Rix, J. M. Hill, E. D. Skillman, D. J. Sand, E. W. Olszewski, D. Zaritsky, D. Thompson, E. Giallongo, R. Ragazzoni, A. DiPaola, J. Farinato, V. Testa, J. Bechtold

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Abstract

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] ∼-1.5 over the entire age of the system. Finally, the data show little, if any, sign of tidal distortion of Leo T.

Original language	English (US)
Pages (from-to)	1112-1119
Number of pages	8
Journal	Astrophysical Journal
Volume	680
Issue number	2
DOIs	https://doi.org/10.1086/587835
State	Published - Jun 20 2008

Keywords

Galaxies: individual (Leo T dSph)
Galaxies: stellar content
Local group

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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De Jong, J. T. A., Harris, J., Coleman, M. G., Martin, N. F., Bell, E. F., Rix, H. W., Hill, J. M., Skillman, E. D., Sand, D. J., Olszewski, E. W., Zaritsky, D., Thompson, D., Giallongo, E., Ragazzoni, R., DiPaola, A., Farinato, J., Testa, V., & Bechtold, J. (2008). The structural properties and star formation history of Leo T from deep LBT photometry. Astrophysical Journal, 680(2), 1112-1119. https://doi.org/10.1086/587835

De Jong, JTA, Harris, J, Coleman, MG, Martin, NF, Bell, EF, Rix, HW, Hill, JM, Skillman, ED, Sand, DJ , Olszewski, EW , Zaritsky, D, Thompson, D, Giallongo, E, Ragazzoni, R, DiPaola, A, Farinato, J, Testa, V & Bechtold, J 2008, 'The structural properties and star formation history of Leo T from deep LBT photometry', Astrophysical Journal, vol. 680, no. 2, pp. 1112-1119. https://doi.org/10.1086/587835

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title = "The structural properties and star formation history of Leo T from deep LBT photometry",

abstract = "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] ∼-1.5 over the entire age of the system. Finally, the data show little, if any, sign of tidal distortion of Leo T.",

keywords = "Galaxies: individual (Leo T dSph), Galaxies: stellar content, Local group",

author = "{De Jong}, {J. T.A.} and J. Harris and Coleman, {M. G.} and Martin, {N. F.} and Bell, {E. F.} and Rix, {H. W.} and Hill, {J. M.} and Skillman, {E. D.} and Sand, {D. J.} and Olszewski, {E. W.} and D. Zaritsky and D. Thompson and E. Giallongo and R. Ragazzoni and A. DiPaola and J. Farinato and V. Testa and J. Bechtold",

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doi = "10.1086/587835",

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T1 - The structural properties and star formation history of Leo T from deep LBT photometry

AU - De Jong, J. T.A.

AU - Harris, J.

AU - Coleman, M. G.

AU - Martin, N. F.

AU - Bell, E. F.

AU - Rix, H. W.

AU - Hill, J. M.

AU - Skillman, E. D.

AU - Sand, D. J.

AU - Olszewski, E. W.

AU - Zaritsky, D.

AU - Thompson, D.

AU - Giallongo, E.

AU - Ragazzoni, R.

AU - DiPaola, A.

AU - Farinato, J.

AU - Testa, V.

AU - Bechtold, J.

PY - 2008/6/20

Y1 - 2008/6/20

N2 - 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] ∼-1.5 over the entire age of the system. Finally, the data show little, if any, sign of tidal distortion of Leo T.

AB - 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] ∼-1.5 over the entire age of the system. Finally, the data show little, if any, sign of tidal distortion of Leo T.

KW - Galaxies: individual (Leo T dSph)

KW - Galaxies: stellar content

KW - Local group

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EP - 1119

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

ER -

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

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