USING ULTRA LONG PERIOD CEPHEIDS TO EXTEND THE COSMIC DISTANCE LADDER TO 100 Mpc AND BEYOND
نویسندگان
چکیده
منابع مشابه
Using Ultra Long Period Cepheids to Extend the Cosmic Distance Ladder to 100 Mpc and Beyond
We examine the properties of 18 long period (80 − 210 days) and very luminous (median absolute magnitude of MI = −7.86 and MV = −6.97) Cepheids to see if they can serve as an useful distance indicator. We find that these Ultra Long Period (ULP) Cepheids have a relatively shallow Period-Luminosity (PL) relation, so in fact they are more “standard candle”-like than classical Cepheids. In the redd...
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We compared period changes derived from O − C diagrams for 63 classical Cepheids from our Galaxy with model calculations. We found that for Cepheids with log P > 1.0 the observed changes are smaller than predicted values, except variable SZ Cas. However some of the first overtone Cepheids, particularly EU Tau and Polaris, change its period much faster than it follows from theory. Summary of the...
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The Discovery of Cepheids and a Distance to Ngc
We discuss a new distance to NGC 5128 (Centaurus A) based on Cepheid variables observed with the Hubble Space Telescope. Twelve F555W (V ) and six F814W (I) epochs of cosmic-ray-split Wide Field Planetary Camera 2 observations were obtained. A total of 56 bona-fide Cepheids were discovered, with periods ranging from 5 to ∼ 50 days; five of these are likely Population II Cepheids of the W Virgin...
متن کاملThe Discovery of Cepheids and a Distance to Ngc 5128
We discuss a new distance to NGC 5128 (Centaurus A) based on Cepheid variables observed with the Hubble Space Telescope. Twelve F555W (V ) and six F814W (I) epochs of cosmic-ray-split Wide Field Planetary Camera 2 observations were obtained. A total of 56 bona-fide Cepheids were discovered, with periods ranging from 5 to ∼ 50 days; five of these are likely Population II Cepheids of the W Virgin...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2009
ISSN: 0004-637X,1538-4357
DOI: 10.1088/0004-637x/695/2/874