Tip of the red giant branch distance for the Sculptor group dwarf ESO 540-032

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dc.contributor.authorJerjen, H
dc.contributor.authorRejkuba, M
dc.date.accessioned2025-01-21T01:30:53Z
dc.date.available2025-01-21T01:30:53Z
dc.date.issued2001
dc.description.abstractWe present the first VI CCD photometry for the Sculptor group galaxy ESO 540-032 obtained at the Very Large Telescope UT1+FORS1. The (I, V - I) colour-magnitude diagram indicates that this intermediate-type dwarf galaxy is dominated by old, metal-poor ([Fe/H] approximate to -1.7 dex) stars, with a small population of slightly more metal-rich ([Fe/H] approximate to -1.3 dex), young (age 150-500 Myr) stars. A discontinuity in the I-band luminosity function is detected at I-0 = 23.44 +/-0.09 mag. Interpreting this feature as the tip of the red giant branch and adopting M-I = -4.20 +/-0.10 mag for its absolute magnitude, we have determined a Population II distance modulus of (m - M)(0) = 27.64 +/-0.14 mag (3.4 +/-0.2 Mpc). This distance confirms ESO 540-032 as a member of the nearby Sculptor group but is significantly larger than a previously reported value based on the Surface Brightness Fluctuation (SBF) method. The results from stellar population synthesis models suggest that the application of the SBF technique on dwarf galaxies with mixed morphology requires a detailed knowledge of the underlying stellar composition and thus offers no advantage over a direct distance measurement using the tip of the red giant branch as distance indicator. We produce the surface brightness profiles for ESO 540-032 and derive the photometric and structural parameters. The global properties follow closely the relations between metallicity and both absolute magnitude and central surface brightness defined by dwarf elliptical galaxies in the Local Group. Finally, we identify and discuss a non-stellar object near the galaxy center which may resemble a globular cluster.
dc.fuente.origenWOS
dc.identifier.doi10.1051/0004-6361:20010389
dc.identifier.issn1432-0746
dc.identifier.urihttps://doi.org/10.1051/0004-6361:20010389
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/96923
dc.identifier.wosidWOS:000169943200009
dc.issue.numero2
dc.language.isoen
dc.pagina.final496
dc.pagina.inicio487
dc.revistaAstronomy & astrophysics
dc.rightsacceso restringido
dc.subjectgalaxies : abundances galaxies : clusters : individual : Sculptor galaxies : dwarf
dc.subjectgalaxies : individual :
dc.subjectESO 540-032
dc.subjectgalaxies : stellar content galaxies : structure
dc.titleTip of the red giant branch distance for the Sculptor group dwarf ESO 540-032
dc.typeartículo
dc.volumen371
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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