Astrophysics (index)

Spectral Energy Distribution

(function or plot of brightness at each wavelength in the spectrum)

Electromagnetic Radiation (EMR)'s Spectral Energy Distribution (SED) is a function, i.e., plot of brightness or Flux density versus the Frequency or Wavelength. When measured on Earth, the effects of Earth Atmosphere are relevant. A "complete" distribution often requires multiple instruments, leading to challenges in calibrating the data. A distribution over a limited bandwidth often provides signatures for specific types sources.

SED Fitting (aka Spectral Energy Distribution Fitting) is a method of classifying distant galaxies, to help determine their age and degree of Star Formation (SF). A challenge is that a young galaxy with Cosmic Dust has a SED across ultraviolet,page, Visible Light, and Near Infrared (NIR) as an old galaxy. A fitting method is Markov-Chain Monte Carlo (MCMC), using random walks around a parameter-space to determine the degree of unique fit between an SED and a known type of object. GalMC is an example of software that takes this approach.


Referenced by:
Galaxy SED
Herschel Orion Protostar Survey (HOPS)
Spitzer Extended Deep Survey (SEDS)
Spectral Line Energy Distribution (SLED)
Stellar Model Atmosphere