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A Photometric Survey of Field Stars in the Large Magellanic Cloud: Probing its Star-Formation History1

Published online by Cambridge University Press:  25 May 2016

T. A. Smecker-Hane ,
J. S. Gallagher III ,
Andrew Cole ,
P. B. Stetson  and
E. Tolstoy
T. A. Smecker-Hane
Affiliation:
Dept. of Physics & Astronomy, Univ. of California, Irvine, CA 92697, USA
J. S. Gallagher III
Affiliation:
Astronomy Dept., Univ. of Wisconsin, Madison, WI 53706, USA
Andrew Cole
Affiliation:
Astronomy Dept., Univ. of Wisconsin, Madison, WI 53706, USA
P. B. Stetson
Affiliation:
National Res. Council of Canada, Herzberg Inst. of Astrophysics, Dominion Astrophysical Obs., Victoria, BC V8X 4M6, Canada
E. Tolstoy
Affiliation:
Space Telescope-European Coordinating Facility, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Muenchen, Germany

Extract

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The Large Magellanic Cloud (LMC) is unique among galaxies in the Local Group in that it is the most massive non-spiral, is relatively gas-rich, and is actively forming stars. Determining its star-formation rate (SFR) as a function of time will be a cornerstone in our understanding of galaxy evolution. The best method of deriving a galaxy's past SFR is to compare the densities of stars in a color-magnitude diagram (CMD), a Hess diagram, with model Hess diagrams. The LMC has a complex stellar population with ages ranging from 0 to ~ 14 Gyr and metallicities from −2 ≲ [Fe/H] ≲ −0.4, and deriving its SFR and simultaneously constraining model input parameters (distance, age-metallicity relation, reddening, and stellar models) requires well-populated CMDs that span the magnitude range 15 ≤ V ≤ 24. Although existing CMDs of field stars in the LMC show tantalizing evidence for a significant burst of star formation that occurred ~ 3 Gyr ago (for examples, see Westerlund et al. 1995; Vallenari et al. 1996; Elson, et al. 1997; Gallagher et al. 1999, and references therein), estimates of the enhancement in the SFR vary from factors of 3 to 50. This uncertainty is caused by the relatively large photometric errors that plague crowded ground-based images, and the small number statistics that plague CMDs created from single Wide Field Planetary Camera 2 (WFPC2) images.

Type
Part 5. Stellar Populations and Surveys
Information
Symposium - International Astronomical Union , Volume 190: New Views of the Magellanic Clouds , 1999 , pp. 343 - 344
Copyright
Copyright © Astronomical Society of the Pacific 1999 

References

Elson, R.A.W., Gilmore, G.F., & Santiago, B.X. 1997, MNRAS, 289, 157 Google Scholar
Gallagher, J.S. III, et al. 1999, this volume Google Scholar
Vallenari, A., et al. 1996, A&A, 309, 367 Google Scholar
Westerlund, B.E., Linde, P., & Lyngå, G. 1995, A&A, 298, 39 Google Scholar