emissivity

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em·is·siv·i·ty

 (ĕm′ĭ-sĭv′ĭ-tē)
n.
The ratio of the radiation emitted by a surface to the radiation emitted by a blackbody at the same temperature.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

emissivity

(ɪmɪˈsɪvɪtɪ; ˌɛm-)
n
(General Physics) a measure of the ability of a surface to radiate energy; the ratio of the radiant flux emitted per unit area to that emitted by a black body at the same temperature. Symbol: ε
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

em•is•siv•i•ty

(ˌɛm əˈsɪv ɪ ti, ˈi mə-)

n.
the ability of a surface to emit radiant energy compared to that of a black body at the same temperature and with the same area.
[1875–80]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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References in periodicals archive ?
Sakalli, "Analytical solutions in rotating linear dilaton black holes: resonant frequencies, quantization, greybody factor, and Hawking radiation," Physical Review D: Particles, Fields, Gravitation and Cosmology, vol.
[4] Boonserm, P., Ngampitipan, T., Visser, M., Regge-Wheeler equation, linear stability, and greybody factors for dirty black holes, Phys.
Similarly we fix the temperature of the dust component to be [T.sub.d] = 18.96 K [3] as this is determined largely by the peak of the dust greybody; we retain the opacity index, [beta], as a free parameter as well as a normalization coefficient.
In BH physics, greybody factors (GFs) modify black-body radiation, or predicted Hawking radiation [1, 2], within the limits of geometrical optics [3].
Although negative values of [beta] are unphysical, values approaching zero (e.g., [31]) are proposed for the long wavelength tail of the greybody spectrum for young stellar objects, which is dominated by large dust grains in circumstellar/protoplanetary disks.
Larsen, "Greybody factors for rotating black holes in four dimensions," Nuclear Physics.
The spectrum of the dust emission has been measured at millimeter and submillimeter wavelengths by the Far Infrared Absolute Spectrophotometer (FIRAS) and can be fitted by a single greybody spectrum of temperature 17.5 K and emissivity [varies] [v.sup.2] [61] at high galactic latitudes.