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2010 August 24, 19:30 SAST
First Cepheid distance to NGC 7793
An international team of astronomers, from Poland, Chile, the UK and the USA, have determined the distance to the spiral galaxy NGC 7793 (in the Scultor Group) from observations of 17 newly-discovered Cepheid-type variables in that galaxy.
Their findings suggest the galaxy lies 3.4 Mpc away, which is (within errors) consistent with two earlier distance estimates obtained by other researchers using different methods.
"The NGC 7793 distance of 3.4 Mpc is almost identical to the one our project had found from Cepheid variables for NGC 247, another spiral member of the Sculptor Group located close to NGC 7793 on the sky. Two other conspicuous spiral galaxies in the Sculptor Group, NGC 55 and NGC 300, are much nearer (1.9 Mpc), confirming the picture of a very elongated structure of the Sculptor Group in the line of sight," as had been previously suggested by other researchers.
The work on NGC 7793 is part of the Araucaria Project, an initiative to improve our knowledge of extragalactic distances. The observations were made with the Warsaw 1.3-m telescope at Las Campanas Observatory, equipped with a 8k x 8k detector giving a field of view of about 35x35 arcmin and a scale of about 0.25 arcseconds per pixel, on 56 nights between 2003 July and 2005 December.
For all the details see "The Araucaria Project. First Cepheid Distance to the Sculptor Group Galaxy NGC 7793 from Variables discovered in a Wide-Field Imaging Survey." arXiv:1008.3040v1 (2010 August 18).
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Two things fill the mind with ever new and increasing admiration and awe, the oftener and the more steadily we reflect on them: the starry heavens above and the moral law within.
Immanuel Kant
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