Stellar populations of the dwarf irregular galaxy WLM

Dante Minniti, Albert A. Zijlstra

Resultado de la investigación: Article

51 Citas (Scopus)

Resumen

We have obtained V-band photometry for 8000 stars, and I-band photometry for 16000 stars in the field of the dwarf irregular galaxy WLM, a member of the Local Group. From the VI color-magnitude diagram we infer metallicities and ages for the stellar populations in the main body and in the halo of WLM. The youngest stars in the galaxy have an age of ∼ 107 Gyr. For the oldest stars we derive an age of > 1010 Gyr and a metallicity of [Fe/H]= - 1.45±0.2. We construct a deep luminosity function, obtaining an accurate distance modulus m-M=24.75±0.1 for this galaxy based on the I-magnitude of the RGB tip and adopting E(V-I)=0.03. We establish the presence of an extended, slightly flattened halo consisting of Population II stars. Cluster D of Ables & Ables (1977, ApJS, 34, 245) is confirmed as the only globular cluster present in the main body of this galaxy. There are no other clusters brighter than I= 19.5. The B - V color gradient observed by Ables & Ables (1977) is shown to be caused by a stellar-population transition, and not a metallicity gradient or dust extinction.

Idioma originalEnglish
Páginas (desde-hasta)147-160
Número de páginas14
PublicaciónAstronomical Journal
Volumen114
N.º1
DOI
EstadoPublished - 1 ene 1997

Huella dactilar

irregular galaxies
dwarf galaxies
metallicity
stars
galaxies
photometry
halos
Population II stars
gradients
color-magnitude diagram
extremely high frequencies
globular clusters
extinction
diagram
dust
luminosity
color

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Minniti, Dante ; Zijlstra, Albert A. / Stellar populations of the dwarf irregular galaxy WLM. En: Astronomical Journal. 1997 ; Vol. 114, N.º 1. pp. 147-160.
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Stellar populations of the dwarf irregular galaxy WLM. / Minniti, Dante; Zijlstra, Albert A.

En: Astronomical Journal, Vol. 114, N.º 1, 01.01.1997, p. 147-160.

Resultado de la investigación: Article

TY - JOUR

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AU - Zijlstra, Albert A.

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AB - We have obtained V-band photometry for 8000 stars, and I-band photometry for 16000 stars in the field of the dwarf irregular galaxy WLM, a member of the Local Group. From the VI color-magnitude diagram we infer metallicities and ages for the stellar populations in the main body and in the halo of WLM. The youngest stars in the galaxy have an age of ∼ 107 Gyr. For the oldest stars we derive an age of > 1010 Gyr and a metallicity of [Fe/H]= - 1.45±0.2. We construct a deep luminosity function, obtaining an accurate distance modulus m-M=24.75±0.1 for this galaxy based on the I-magnitude of the RGB tip and adopting E(V-I)=0.03. We establish the presence of an extended, slightly flattened halo consisting of Population II stars. Cluster D of Ables & Ables (1977, ApJS, 34, 245) is confirmed as the only globular cluster present in the main body of this galaxy. There are no other clusters brighter than I= 19.5. The B - V color gradient observed by Ables & Ables (1977) is shown to be caused by a stellar-population transition, and not a metallicity gradient or dust extinction.

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