When the researchers simulated the Hitomi spectrum by adding this absorption line
to the hot gas' emission line seen with Chandra and XMM-Newton, they found no evidence in the summed spectrum for either absorption or emission of X-rays at 3.
For the integrated line spectroscopy the magnitude to be measured is the area under a few absorption lines
Since the late 1960s, observers have been checking to see whether the spacings between the absorption lines
in quasar spectra differ slightly from those observed in laboratory experiments.
Furthermore, infrared DIAL systems are preferred because they are highly sensitive to the laser energy, are relatively eye safe, and more importantly, are in the spectral range where most molecular-specific absorption lines
The more gas along the lights path, the deeper the absorption lines
By placing a gas cell between their spectrograph and the Canada-France-Hawaii Telescope, they superimpose narrow absorption lines
onto the observed stellar spectra.
By comparing the positions of the absorption lines
measured by the telescope with the positions measured in the laboratory, they can tell whether alpha is different near the white dwarf.
Quasars whose spectra show such broad absorption lines
are known as "BAL quasars.
The portable remote detection system integrates PAS and open-field acoustic resonator techniques to detect chemicals and explosives, inspect absorption lines
, and measure absorption intensities.
Evolution of galaxies and the intergalactic matter can be studied by looking at quasar absorption lines