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For example, consider a 1 Jy signal from a radio source at a redshift of 1, at a frequency of 1.4 GHz. Ned Wright's cosmology calculator calculates a luminosity distance for a redshift of 1 to be 6701 Mpc = 2×10 26 m giving a radio luminosity of 10 −26 × 4 π (2×10 26) 2 / (1 + 1) (1 + 2) = 6×10 26 W Hz −1.
The object's actual luminosity is determined using the inverse-square law and the proportions of the object's apparent distance and luminosity distance. Another way to express the luminosity distance is through the flux-luminosity relationship, = where F is flux (W·m −2), and L is luminosity (W). From this the luminosity distance (in meters ...
In astronomy, absolute magnitude (M) is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale; the more luminous (intrinsically bright) an object, the lower its magnitude number.
A related quantity is integrated luminosity (L int), which is the integral of the luminosity with respect to time: [1] = . The luminosity and integrated luminosity are useful values to characterize the performance of a particle accelerator. In particular, all collider experiments aim to maximize their integrated luminosities, as the higher the ...
For example, M V is the magnitude at 10 parsecs in the V passband. A bolometric magnitude (M bol ) is an absolute magnitude adjusted to take account of radiation across all wavelengths; it is typically smaller (i.e. brighter) than an absolute magnitude in a particular passband, especially for very hot or very cool objects.
In astrophysics, L is used for luminosity (energy per unit time, equivalent to power) ... Physics for Scientists and Engineers: With Modern Physics (6th ed.).
So: = where L is the luminosity, σ is the Stefan–Boltzmann constant, R is the stellar radius and T is the effective temperature. This formula can then be rearranged to calculate the temperature: T = L 4 π R 2 σ 4 {\displaystyle T={\sqrt[{4}]{\frac {L}{4\pi R^{2}\sigma }}}} or alternatively the radius: R = L 4 π σ T 4 {\displaystyle R ...
In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. The SI unit of luminous intensity is the candela (cd), an SI base unit.