Astronomy and Astrophysics – Astrophysics
Scientific paper
1997-08-20
Astronomy and Astrophysics
Astrophysics
To appear in ApJ(letters). 11 pages, Latex, uses AASTeX v4.0
Scientific paper
10.1086/310934
The broad absorption bump at 2175 angstrom due to dust, which is ubiquitous in the Galaxy and is seen in the Magellanic clouds, is also seen in a composite spectrum of Mg II absorbers. The composite absorber spectrum is obtained by taking the geometric mean of 92 quasar spectra after aligning them in the restframe of 96 absorbers. By aligning the spectra according to absorber redshifts we reinforce the spectral features of the absorbers, and smooth over possible bumps and wiggles in the emission spectra as well as small features in the flat fielding of the spectra. The width of the observed absorption feature is 200-300 angstrom (FWHM), or 0.4-0.6 (micron)^{-1} and the central wavelength is 2240 angstrom. These are somewhat different from the central wavelength of 2176 angstrqom and FWHM=0.8-1.25 (micron)^{-1} found in the Galaxy. Simulations show that this discrepancy between the properties of the 2175 angstrom feature in Mg II absorbers and Galactic ISM can be mostly explained by the different methods used to measure them.
No associations
LandOfFree
Detection of the 2175 angstrom dust feature in Mg II absorption systems does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Detection of the 2175 angstrom dust feature in Mg II absorption systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Detection of the 2175 angstrom dust feature in Mg II absorption systems will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-183168