New results on the structure and stellar content of the outer regions of the SMC

Surface distribution contour maps of the HB/clump population and the < 1 Gyr main sequence population for the outer regions of the Small Magellanic Cloud (SMC) are presented. Aspects of the stellar population synthesis, large-scale structure and evolutionary history of the SMC halo are discussed.

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Stellar Populations in Mixed Pairs of Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900109477 ◽

1995 ◽

Vol 164 ◽

pp. 434-434 ◽

Cited By ~ 1

Author(s):

D.F. De Mello ◽

W.C. Keel ◽

J.W. Sulentic ◽

R. Rampazzo

Keyword(s):

Star Formation ◽

Stellar Population ◽

Elliptical Galaxy ◽

Star Formation History ◽

Population Synthesis ◽

Early Type ◽

Stellar Content ◽

Stellar Population Synthesis ◽

History Of ◽

Early Type Galaxy

The interpration of the interaction in galaxies is simplified in mixed pairs (E+S) because most or all of the cold gas can be traced to an origin in a single galaxy (S). We used spectroscopy, imaging, far–IR, and stellar population synthesis to study the stellar content and history of star formation in the nuclear region of the early–type galaxy in the mixed pair AM0327–285. We used the procedure for stellar population synthesis developed by Bica (1988) to estimate the star-formation history of the nucleus of the elliptical galaxy. The method uses a library of star clusters, and estimates the chemical evolution in a test population with two parameters: age and metallicity; no assumptions on gravity or details of stellar evolution are necessary, and the IMF is implicit in the cluster spectra. The procedure allows one to both determine the chemical enrichment and date successive generations of star formation. The result indicates that the dominant population is old and metal–rich ([Z/Z]⊙=0.3), while ~ 10% of the flux at 5870 Å arises from a young stellar population (age ≤ 5 × 108 yr), confirming that this early-type galaxy had recent star formation as suggested also by photometry and far–IR data (de Mello et al 1994). This age is close to several estimates of the characteristic timescale of the interaction, suggesting that the mass influx associated with this star formation occurred as a result of an earlier phase of the interaction and not as a result of the present geometry of the pair.

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The star formation history of the Fornax dwarf spheroidal galaxy

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310003200 ◽

2009 ◽

Vol 5 (S262) ◽

pp. 353-354

Author(s):

Enrico V. Held ◽

Eline Tolstoy ◽

Luca Rizzi ◽

Mary Cesetti ◽

Andrew A. Cole ◽

...

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Stellar Population ◽

Main Sequence ◽

Dwarf Galaxy ◽

Star Formation History ◽

Stellar Content ◽

Formation History ◽

First Results ◽

History Of

AbstractWe present the first results of a comprehensive HST study of the star-formation history of Fornax dSph, based on WFPC2 imaging of 7 Fornax fields. Our observations reach the oldest main-sequence turnoffs, allowing us to address fundamental questions of dwarf galaxy evolution, such as the spatial variations in the stellar content, and whether the old stellar population is made up of stars formed in a very early burst or the result of a more continuous star formation.

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Stellar population synthesis: Application To Galactic Bulges

Symposium - International Astronomical Union ◽

10.1017/s0074180900123162 ◽

1993 ◽

Vol 153 ◽

pp. 133-150

Author(s):

N. Arimoto

Keyword(s):

Observational Data ◽

Stellar Population ◽

Stellar Populations ◽

Population Synthesis ◽

Firm Conclusion ◽

Formation History ◽

Stellar Population Synthesis ◽

Central Regions ◽

History Of ◽

Metallicity Distribution

The stellar populations give traces of the formation history of the bulges. The metallicity distribution of K-giants in the Galactic bulge resembles to that of the giant ellipticals. There seems to be no conspicuous colour-magnitude relation intrinsic to the bulges. This can be explained if the bulges formed by the dissipative collapse of central regions of proto-galaxies followed by the supernova-driven bulge wind which was induced later than the dwarf ellipticals of the similar mass (the biased wind). Unfortunately, the observational data available at present of stellar populations of the bulges are not yet sufficient to get a firm conclusion on the origin of the bulges.

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Stellar Population Synthesis and Star Counts to Constrain the Galactic Structure

International Astronomical Union Colloquium ◽

10.1017/s0252921100106815 ◽

1984 ◽

Vol 78 ◽

pp. 325-327

Author(s):

Annie Robin ◽

Michel Creze

Keyword(s):

Stellar Population ◽

Main Sequence ◽

Absolute Magnitude ◽

Galactic Structure ◽

Red Giants ◽

Population Synthesis ◽

Main Sequence Stars ◽

Space Density ◽

Stellar Population Synthesis

AbstractOur model of stellar population synthesis allows to derive synthetic star counts and distribution of colors, ages, and spectral types of stars in any given direction of observations. Here we compare results of the model with the distribution of stars in space and in absolute magnitude of stars of Gilmore and Reid. We find a small disagreement between observations of GR and predictions of our model in the space density of stars of 4 < Mv < 5. Ue show that this discrepancy can well be explained by a contamination of their sample of assumed main sequence stars by red giants and subgiants.

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