Physics:Spectral energy distribution
A spectral energy distribution (SED) is a plot of energy versus frequency or wavelength of light (not to be confused with a 'spectrum' of flux density vs frequency or wavelength).[1] It is used in many branches of astronomy to characterize astronomical sources. For example, in radio astronomy they are used to show the emission from synchrotron radiation, free-free emission and other emission mechanisms. In infrared astronomy, SEDs can be used to classify young stellar objects.
Detector for spectral energy distribution
The count rates observed from a given astronomical radiation source have no simple relationship to the flux from that source, such as might be incident at the top of the Earth's atmosphere.[2] This lack of a simple relationship is due in no small part to the complex properties of radiation detectors.[2]
These detector properties can be divided into
- those that merely attenuate the beam, including
- residual atmosphere between source and detector,
- absorption in the detector window when present,
- quantum efficiency of the detecting medium,[2]
- those that redistribute the beam in detected energy, such as
- fluorescent photon escape phenomena,
- inherent energy resolution of the detector.[2]
See also
- Astronomical radio source
- Astronomical X-ray sources
- Background radiation
- Bremsstrahlung
- Cosmic microwave background spectral distortions
- Cyclotron radiation
- Electromagnetic radiation
- Synchrotron radiation
- Wavelength dispersive X-ray spectroscopy
References
- ↑ "SED plots - CoolWiki" (in en). http://coolwiki.ipac.caltech.edu/index.php/SED_plots. Retrieved 27 February 2018.
- ↑ 2.0 2.1 2.2 2.3 Dolan JF (Aug 1972). "The Direct Reduction of Astronomical X-Ray Spectra". Astrophys. Space Sci. 17 (2): 472–81. doi:10.1007/BF00642917. Bibcode: 1972Ap&SS..17..472D.
Further reading
- Eberhard Haug; Werner Nakel (2004). The elementary process of Bremsstrahlung. River Edge NJ: World Scientific. p. Scientific lecture notes in physics, vol. 73. ISBN 978-981-238-578-9. https://books.google.com/books?id=v4FMtIwTri8C&q=bremsstrahlung+haug.
- Jakob Walcher; Brent Groves. "Fitting the spectral energy distributions of galaxies". Archived from the original on 2014-08-14. https://web.archive.org/web/20140814041031/http://www.sedfitting.org/SED08/Paper_vs1.0_online/walcher_ms.html.
External links
- The High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA
- The Science of Spectroscopy
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