Hubble Space Telescope Photometry of the Dwarf Spheroidal Galaxy ESO 410-G005

We present HST WFPC2 imaging of the nearby low-surface-brightness dwarf spheroidal galaxy ESO 410-G005, which has been resolved into stars for the first time. The resulting color-magnitude diagram for about 2500 stars shows a red giant branch branch with a tip at I=(22.4+-0.15), which yields a dista...

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Bibliographic Details
Published in:arXiv.org 2000-07
Main Authors: Karachentsev, Igor D, Sharina, Margarita E, Grebel, Eva K, Dolphin, Andrew E, Geisler, Doug, Guhathakurta, Puragra, Hodge, Paul W, Karachentseva, Valentina E, Sarajedini, Ata, Seitzer, Patrick
Format: Article
Language:English
Subjects:
Asymptotic giant branch stars
Color-magnitude diagram
Dwarf galaxies
European Southern Observatory
Hubble Space Telescope
Local group (astronomy)
Metallicity
Object recognition
Photometry
Separation
Space telescopes
Spheroidal galaxies
Stars & galaxies
Surface brightness
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Summary:We present HST WFPC2 imaging of the nearby low-surface-brightness dwarf spheroidal galaxy ESO 410-G005, which has been resolved into stars for the first time. The resulting color-magnitude diagram for about 2500 stars shows a red giant branch branch with a tip at I=(22.4+-0.15), which yields a distance of D=(1.9+-0.2) Mpc. ESO 410-G005 is found to be metal-poor with a mean metallicity of (-1.8+-0.4) dex estimated from its red giant branch. Upper asymptotic giant branch stars appear to be present near the center of the galaxy, indicative of a substantial, centrally concentrated intermediate-age population, unless these objects are artifacts of crowding. Previous studies did not detect ESO 410-G005 in H alpha or in HI. ESO 410-G005 is a probable member of the Sculptor group. Its linear separation from the nearest spiral, NGC 55, is 230 kpc on the sky. The deprojected separation ranges from 340 to 615 kpc depending on the assumed distance of NGC 55. ESO 410 G005 appears to be a relatively isolated dSph within the Sculptor group. Its absolute magnitude, Mv = (-12.1+-0.2) mag, its central surface brightness, mu_V = (22.7+-0.1) mag/arcsec^2, and its mean metallicity, [Fe/H] = (-1.8+-0.4) dex, follow the trend observed for dwarf galaxies in the Local Group. (abridged)
ISSN:2331-8422
DOI:10.48550/arxiv.0007001