منابع مشابه
Cepheid metallicity and Hubble constant
This study combines data from a set of seven Cepheid-calibrated galaxies in Virgo, Leo I and Fornax and four supernovæ with known metallicities, including metallicity corrections to the Cepheid distances, in order to determine a consistent mean value for the Hubble constant. We derive Virgo and Coma distances over different paths, starting from the metallicity corrected Cepheid distances of Vir...
متن کاملCepheid calibration of type Ia Supernovae and the Hubble constant
We investigate how a different calibration of the Cepheid Period-Luminosity (PL) relation taking into account the metallicity corrections, affects the absolute magnitude calibration of Supernovae (SNe) Ia and, in turn, the determination of the Hubble constant H0. We exploit SN Ia light curves from literature and previously unpublished data, to build the MB – ∆m15(B) relation and we calibrate th...
متن کاملHipparcos Parallaxes and the Cepheid Distance Scale
Hipparcos parallaxes have recently become available for a sample of Galactic Cepheids, and we have used these new distances to calibrate the Cepheid periodluminosity (PL) relation at six wavelengths (BV IJHK). Comparing these calibrations with previously published multiwavelength PL relations we find agreement to within 0.07 ± 0.14 mag, or 4 ±7% in distance. Unfortunately, the current parallax ...
متن کاملHubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-luminosity Relations
We present new absolute trigonometric parallaxes and relative proper motions for nine Galactic Cepheid variable stars: l Car, ζ Gem, β Dor, W Sgr, X Sgr, Y Sgr, FF Aql, T Vul, and RT Aur. We obtain these results with astrometric data from Fine Guidance Sensor 1r, a white-light interferometer on Hubble Space Telescope. We find absolute parallaxes in milliseconds of arc: l Car, 2.01± 0.20 ; ζ Gem...
متن کاملThe Cepheid PL Zero - Point from HipparcosTrigonometrical Parallaxes ?
Hipparcos trigonometrical parallaxes of Cepheid variables are used to derive a zero-point for the PL relation. Adopting a slope from the LMC, the relation is found to be, The standard error of the zero-point is 0.10 mag. Together with metallicity corrections this corresponds to distance moduli of 18:70 0:10 for the LMC and 24:77 0:11 for M31. Some implications of these results are discussed. Es...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2007
ISSN: 0035-8711,1365-2966
DOI: 10.1111/j.1365-2966.2007.11972.x