The baseline noise level was determined to be less than 1 x [10.sup.-3] based on a 1 - [sigma] standard deviation of the residual of the
absorption line fit.
Moreover they have significant
absorption lines within the wavelength range discussed.
However, the wide field of view provided by SpIOMM allows observations of hundreds of stars simultaneously, as well as extended
absorption line sources, which compensates for the multiplex disadvantage.
The intensity [S.sup.B.sub.A] in [cm.sup.-1]/(cm atm) of an individual
absorption line with frequency [v.sub.AB] in [cm.sup.-1] is given by [7]:
The width of this "broad
absorption line" (BAL) measures the speed of the quasar's wind.
The main difference between SRM 2517a and its predecessor, SRM 2517, is the use of lower pressure in the acetylene cell to produce narrower
absorption lines. The lines are about a factor of four narrower than those of SRM 2517.
Diffuse Interstellar Bands (DIB) are broad
absorption lines in the spectra of stars indicating the existence of clouds of complex, unidentified molecules in the space between the stars.
A decade ago, researchers discovered that some of the
absorption lines are much stronger than others.
In Fleming's classification, an A star displayed only hydrogen
absorption lines in its spectrum, while a B star also displayed prominent Orion lines, named after the
absorption lines found in many stars near the Orion constellation and later discovered to come from the element helium.
In 19 of the quasars, the broad
absorption lines had disappeared.
"In this frequency range, gases tend to have very strong, narrow
absorption lines. So, for example, you can tell if you're looking at a cylinder filled with carbon dioxide or carbon monoxide.