Line Profile
A plot of intensity versus wavelength across a spectral line.
Line Spectrum ...
LINE PROFILE
A graphical plot of the variation of intensity across a spectrum line.
LITHIUM STARS ...
See Line Profile. [H76]
Program Stars
The stars being observed or measured, as contrasted with the comparison stars. [H76] ...
P Cygni line profiles
During the late nineteenth century, many astronomers were engaged in a great race to catalog the universe.
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230. Line Profile
A graph of light intensity verses wavelength showing the shape of an absorption line Liquid.
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231. Lobate Scarp
A curved cliff such as those found on Mercury.
When looking at the spectrum of this star, a curious profile of the absorbtion lines can be seen: Instead of of a more or less symmetric line profile a broad trough with an emission peak at the red side of the trough.
The form of the line profile is determined by the functional form of the perturbing force with respect to distance from the perturbing particle. There may also be a shift in the line center.
The line profiles give an obvious distinction between the narrow-line region (NLR) and the broad-line region (BLR) (though there is of course a transition zone, and these are extremes of a continuous gas distribution).
Precise radial velocity measurements [1] have shown variations in the stellar radial velocities and spectral line profiles. The oscillations are multi-periodic with periods from several hours up to several days.
The 21-cm line profile has several doppler shifted peaks that are narrow and well-defined (see the figure below). Using the known rotation curve, you can convert the doppler speeds of the peaks to get the distance to the hydrogen producing each peak.
Even though this is based on only one line, the line profile and continuum dropoff on the blue side look very much like Lyman alpha lines in other high redshift objects. Esther Hu et al claim an object at z = 5.
The challenge facing astronomers is to unravel the extent to which each mechanism contributes to spectral-line profiles and so obtain meaningful information about the source of the lines.
 See also: Emission, Spectrum, Solar, Light, Distance
  
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