Results 251 to 260 of about 1,090,152 (292)
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Cepheids As Distance Indicators
Annual Review of Astronomy and Astrophysics, 1987This review attempts to summarize the various ways of determining Cepheid reddenings and luminosities and the zero points of the Cepheid period-luminosity and period-luminosity-color relations. The methods of determining luminosities that are discussed involve Cepheid parallaxes, Cepheid proper motions and radial velocities, Cepheids in clusters and ...
M. W. Feast, A. R. Walker
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Old-Aged Primary Distance Indicators
Space Science Reviews, 2018Old-aged stellar distance indicators are present in all Galactic structures (halo, bulge, disk) and in galaxies of all Hubble types and, thus, are immensely powerful tools for understanding our Universe. Here we present a comprehensive review for three primary standard candles from Population II: (i) RR Lyrae type variables (RRL), (ii) type II Cepheid ...
Beaton, Rachael L. +10 more
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Publications of the Astronomical Society of the Pacific, 1986
From published photographic observations the dispersion in the maximum magnitude versus rate of decline relation for novae in M31 is σ = 0.28 mag, from which the intrinsic dispersion is found to be σ0 < 0.14 mag. This is far smaller than the 1.5 mag range in distance moduli that corresponds to 50 < H < 100 km s-1Mpc-1.
S. van den Bergh, C. J. Pritchet
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From published photographic observations the dispersion in the maximum magnitude versus rate of decline relation for novae in M31 is σ = 0.28 mag, from which the intrinsic dispersion is found to be σ0 < 0.14 mag. This is far smaller than the 1.5 mag range in distance moduli that corresponds to 50 < H < 100 km s-1Mpc-1.
S. van den Bergh, C. J. Pritchet
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Verification of Optical Distance Indicator Accuracy
Medical Dosimetry, 1991The purpose of the optical distance indicator, or rangefinder, is to set the patient at a certain distance from the radiotherapy source when using either fixed SSD or an isocentric technique. If the distance that is set is not accurate, then the tumor dose calculated using this distance is also incorrect.
S, Burch, A M, Vann, J, Arazie
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Relation between Distance-Based Topological Indices
Journal of Chemical Information and Computer Sciences, 2000The pi-index of the line graph of the molecular graph of an alkane is shown to be related to the pi, Harary, and reciprocal Wiener indices of that alkane. Thus a mathematical relation between several distance-based topological indices is obtained.
I, Gutman, Z, Tomović
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2003
We review the status of Novae as distance indicators. We discuss the problem of the correct calibration of the life-luminosity relationship for Galactic novae on the basis of the properties of the M31 and LMC nova populations and show that linear regressions, normally used to interpolate the Galactic data, fit M31 and LMC only as a very rough first ...
Roberto Gilmozzi, Massimo Della Valle
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We review the status of Novae as distance indicators. We discuss the problem of the correct calibration of the life-luminosity relationship for Galactic novae on the basis of the properties of the M31 and LMC nova populations and show that linear regressions, normally used to interpolate the Galactic data, fit M31 and LMC only as a very rough first ...
Roberto Gilmozzi, Massimo Della Valle
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On metagalactic distance-indicators
Vistas in Astronomy, 1956Abstract First, an historical outline is given of the “Island-Universe” conception ( Galilei , 1609), and of the development of our knowledge of the nebulae. The cosmological views of the eighteenth century are surveyed, and in particular the developments in England during the Restoration Period (1660–1700), the Augustan Age (1700–1745), and the era ...
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Indicators of Success in Distance Education
CIN: Computers, Informatics, Nursing, 2005Distance education offers many advantages to students, faculty, and educational institutions. Despite these advantages, distance education classes historically have higher dropout rates than do the courses taught in the traditional, face-to-face setting. Current research includes information related to technology, teaching tips, and resources for these
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Indicators of Genetic Distance
1974In recent years, considerable attention has been devoted to measuring the genetic distance between populations, and several indices of distance have been proposed and used.
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