Stellar populations in three outer fields of the Large Magellanic Cloud

Marla C. Geha, Jon A. Holtzman, Jeremy R. Mould, John S. Gallagher, Alan M. Watson, Andrew A. Cole, Carl J. Grillmair, Karl R. Stapelfeldt, Gilda E. Ballester, Christopher J. Burrows, John T. Clarke, David Crisp, Robin W. Evans, Richard E. Griffiths, J. Jeff Hester, John G. Hoessel, Paul Scowen, John T. Trauger, James A. Westphal

Research output: Contribution to journalArticle

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Abstract

We present Hubble Space Telescope photometry for three fields in the outer disk of the Large Magellanic Cloud (LMC) extending approximately 4 mag below the faintest main-sequence turnoff. We cannot detect any strongly significant differences in the stellar populations of the three fields based on the morphologies of the color-magnitude diagrams, the luminosity functions, and the relative numbers of stars in different evolutionary stages. Our observations therefore suggest similar star formation histories in these regions, although some variations are certainly allowed. The fields are located in two regions of the LMC: one is in the northeast and two are located in the northwest. Under the assumption of a common star formation history, we combine the three fields with ground-based data at the same location as one of the fields to improve statistics for the brightest stars. We compare this stellar population with those predicted from several simple star formation histories suggested in the literature, using a combination of the R-method of Bertelli et al. (1992) and comparisons with the observed luminosity function. The only model we consider that is not rejected by the observations is one in which the star formation rate is roughly constant for most of the LMC's history and then increases by a factor of 3 about 2 Gyr ago. Such a model has roughly equal numbers of stars older and younger than 4 Gyr, and thus is not dominated by young stars. This star formation history, combined with a closed-box chemical evolution model, is consistent with observations that the metallicity of the LMC has doubled in the past 2 Gyr.

Original languageEnglish (US)
Pages (from-to)1045-1056
Number of pages12
JournalAstronomical Journal
Volume115
Issue number3
DOIs
StatePublished - Jan 1 1998

Fingerprint

Magellanic clouds
histories
star formation
history
stars
luminosity
color-magnitude diagram
chemical evolution
star formation rate
Hubble Space Telescope
metallicity
photometry
boxes
diagram
statistics
young

Keywords

  • Galaxies: stellar content
  • Magellanic clouds
  • Stars: evolution

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Geha, M. C., Holtzman, J. A., Mould, J. R., Gallagher, J. S., Watson, A. M., Cole, A. A., ... Westphal, J. A. (1998). Stellar populations in three outer fields of the Large Magellanic Cloud. Astronomical Journal, 115(3), 1045-1056. https://doi.org/10.1086/300252

Stellar populations in three outer fields of the Large Magellanic Cloud. / Geha, Marla C.; Holtzman, Jon A.; Mould, Jeremy R.; Gallagher, John S.; Watson, Alan M.; Cole, Andrew A.; Grillmair, Carl J.; Stapelfeldt, Karl R.; Ballester, Gilda E.; Burrows, Christopher J.; Clarke, John T.; Crisp, David; Evans, Robin W.; Griffiths, Richard E.; Hester, J. Jeff; Hoessel, John G.; Scowen, Paul; Trauger, John T.; Westphal, James A.

In: Astronomical Journal, Vol. 115, No. 3, 01.01.1998, p. 1045-1056.

Research output: Contribution to journalArticle

Geha, MC, Holtzman, JA, Mould, JR, Gallagher, JS, Watson, AM, Cole, AA, Grillmair, CJ, Stapelfeldt, KR, Ballester, GE, Burrows, CJ, Clarke, JT, Crisp, D, Evans, RW, Griffiths, RE, Hester, JJ, Hoessel, JG, Scowen, P, Trauger, JT & Westphal, JA 1998, 'Stellar populations in three outer fields of the Large Magellanic Cloud', Astronomical Journal, vol. 115, no. 3, pp. 1045-1056. https://doi.org/10.1086/300252
Geha MC, Holtzman JA, Mould JR, Gallagher JS, Watson AM, Cole AA et al. Stellar populations in three outer fields of the Large Magellanic Cloud. Astronomical Journal. 1998 Jan 1;115(3):1045-1056. https://doi.org/10.1086/300252
Geha, Marla C. ; Holtzman, Jon A. ; Mould, Jeremy R. ; Gallagher, John S. ; Watson, Alan M. ; Cole, Andrew A. ; Grillmair, Carl J. ; Stapelfeldt, Karl R. ; Ballester, Gilda E. ; Burrows, Christopher J. ; Clarke, John T. ; Crisp, David ; Evans, Robin W. ; Griffiths, Richard E. ; Hester, J. Jeff ; Hoessel, John G. ; Scowen, Paul ; Trauger, John T. ; Westphal, James A. / Stellar populations in three outer fields of the Large Magellanic Cloud. In: Astronomical Journal. 1998 ; Vol. 115, No. 3. pp. 1045-1056.
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abstract = "We present Hubble Space Telescope photometry for three fields in the outer disk of the Large Magellanic Cloud (LMC) extending approximately 4 mag below the faintest main-sequence turnoff. We cannot detect any strongly significant differences in the stellar populations of the three fields based on the morphologies of the color-magnitude diagrams, the luminosity functions, and the relative numbers of stars in different evolutionary stages. Our observations therefore suggest similar star formation histories in these regions, although some variations are certainly allowed. The fields are located in two regions of the LMC: one is in the northeast and two are located in the northwest. Under the assumption of a common star formation history, we combine the three fields with ground-based data at the same location as one of the fields to improve statistics for the brightest stars. We compare this stellar population with those predicted from several simple star formation histories suggested in the literature, using a combination of the R-method of Bertelli et al. (1992) and comparisons with the observed luminosity function. The only model we consider that is not rejected by the observations is one in which the star formation rate is roughly constant for most of the LMC's history and then increases by a factor of 3 about 2 Gyr ago. Such a model has roughly equal numbers of stars older and younger than 4 Gyr, and thus is not dominated by young stars. This star formation history, combined with a closed-box chemical evolution model, is consistent with observations that the metallicity of the LMC has doubled in the past 2 Gyr.",
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AU - Watson, Alan M.

AU - Cole, Andrew A.

AU - Grillmair, Carl J.

AU - Stapelfeldt, Karl R.

AU - Ballester, Gilda E.

AU - Burrows, Christopher J.

AU - Clarke, John T.

AU - Crisp, David

AU - Evans, Robin W.

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AU - Hester, J. Jeff

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N2 - We present Hubble Space Telescope photometry for three fields in the outer disk of the Large Magellanic Cloud (LMC) extending approximately 4 mag below the faintest main-sequence turnoff. We cannot detect any strongly significant differences in the stellar populations of the three fields based on the morphologies of the color-magnitude diagrams, the luminosity functions, and the relative numbers of stars in different evolutionary stages. Our observations therefore suggest similar star formation histories in these regions, although some variations are certainly allowed. The fields are located in two regions of the LMC: one is in the northeast and two are located in the northwest. Under the assumption of a common star formation history, we combine the three fields with ground-based data at the same location as one of the fields to improve statistics for the brightest stars. We compare this stellar population with those predicted from several simple star formation histories suggested in the literature, using a combination of the R-method of Bertelli et al. (1992) and comparisons with the observed luminosity function. The only model we consider that is not rejected by the observations is one in which the star formation rate is roughly constant for most of the LMC's history and then increases by a factor of 3 about 2 Gyr ago. Such a model has roughly equal numbers of stars older and younger than 4 Gyr, and thus is not dominated by young stars. This star formation history, combined with a closed-box chemical evolution model, is consistent with observations that the metallicity of the LMC has doubled in the past 2 Gyr.

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KW - Magellanic clouds

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