Problems Concerning the Extragalactic Distance Scale
نویسندگان
چکیده
منابع مشابه
The Extragalactic Distance Scale
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...
متن کاملThe Extragalactic Distance Scale
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...
متن کاملThe Extragalactic Distance Scale without Cepheids
Distances of galaxies in the Hubble Space Telescope Key Project are based on the Cepheid period-luminosity relation. An alternative basis is the tip of the red giant branch. Using archival HST data, we calibrate the infrared TullyFisher relation using 14 galaxies with tip of the red giant branch measurements. Compared with the Key Project, a higher value of the Hubble Constant by 10% ± 7% is in...
متن کاملEclipsing Binaries: Tools for Calibrating the Extragalactic Distance Scale
In the last decade, over 7000 eclipsing binaries have been discovered in the Local Group through various variability surveys. Measuring fundamental parameters of these eclipsing binaries has become feasible with 8 meter class telescopes, making it possible to use eclipsing binaries as distance indicators. Distances with eclipsing binaries provide an independent method for calibrating the extrag...
متن کاملA Technique for Determining the Extragalactic Distance Scale
We propose a method of distance determination based on the internal structure and dynamics of disk galaxies. The method relies on the universal luminosity pro le of a stellar disk represented by an exponential law. Calibrating nearby galaxies with known distances, it is found that the scale length of the disk is tightly correlated with the speci c combination of central surface brightness and r...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1972
ISSN: 0074-1809
DOI: 10.1017/s0074180900005817