The Extragalactic Distance Scale and the Hubble Constant
نویسندگان
چکیده
منابع مشابه
Anisotropy in the Hubble constant as observed in the HST Extragalactic Distance Scale Key Project results
Based on general relativity, it can be argued that deviations from a uniform Hubble flow should be thought of as variations in the Universe’s expansion velocity field, rather than being thought of as peculiar velocities with respect to a uniformly expanding space. The aim of this paper is to use the observed motions of galaxies to map out variations in the Universe’s expansion, and more importa...
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Significant progress has been made during the last 10 years toward resolving the debate over the expansion rate of the Universe. The current value of the Hubble parameter, H 0, is now arguably known with an accuracy of 10%, largely due to the tremendous increase in the number of galaxies in which Cepheid variable stars have been discovered. Increasingly accurate secondary distance indicators, m...
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Cepheid variables are used to derive a Virgo cluster distance of 16.0 ± 1.5 Mpc. In conjunction with the Coma velocity and the well-established Coma/Virgo distance ratio, this yields a Hubble parameter H = 81 ± 8 km s o-1 Mpc. By combining this value with an age of the Universe / 16.8 ± 2.1 Gyr, that-1 is derived from the metal-poor globular cluster M92, one obtains f (5, %) / 1.39 ± 0.22. This...
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This paper presents the calibration of BVRIH−0.5 Tully–Fisher relations based on Cepheid distances to 21 galaxies within 25 Mpc, and 23 clusters within 10,000 km s−1. These relations have been applied to several distant cluster surveys in order to derive a value for the Hubble constant, H0, mainly concentrating on an I–band all–sky survey by Giovanelli and collaborators which consisted of total...
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We report the detection of Cepheids and a new distance to the spiral galaxy NGC 2541, based on data obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope (HST). A total of 25 exposures (divided into 13 epochs) are obtained using the F555W filter (transformed to Johnson V), and nine exposures (divided into five epochs) using the F814W filter (transformed to Cous...
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ژورنال
عنوان ژورنال: Europhysics News
سال: 1984
ISSN: 0531-7479,1432-1092
DOI: 10.1051/epn/19841511010