Abstract

view Abstract Citations (21) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the possible identification of Mg II lambda 2934 emission in QSOs. Grandi, S. A. ; Phillips, M. M. Abstract A broad weak emission feature at a rest wavelength of approximately 2950 A is found to be nearly always present in QSO spectra. The identifications with forbidden Mg V, Ne V, or O I transitions which have been suggested in the past do not appear likely. An identification with several lines of Fe II does not seem probable either. A correlation of the strength of 2950-A emission with the Mg II 2798-A resonance doublet suggests that the emission may be Mg II at 2934 A. Two excitation mechanisms for Mg II 2934 A are suggested and discussed: fluorescence by H I L-beta and fluorescence by N V 1240 A. Both mechanisms are shown to lead to appreciable excitation of Mg II 2934 A with respect to Mg II 2798 A. A problem with this identification is that the centroid of the broad 2950-A feature is not aligned exactly with Mg II 2934 A when the redshift determined from the other emission peaks is used. However, it is suggested that Mg II 2934 A may be consistent with a redshift determined from the centroid of the broad components of the Balmer lines. Evidence in support of the proposed emission mechanisms is outlined. Problems such as the apparent weakness of Mg II 1737-, 1750-A emission in the spectra of high-redshift QSOs are also discussed. Publication: The Astrophysical Journal Pub Date: March 1978 DOI: 10.1086/155921 Bibcode: 1978ApJ...220..426G Keywords: Magnesium; Metal Ions; Near Ultraviolet Radiation; Quasars; Ultraviolet Spectra; Astronomical Spectroscopy; Balmer Series; Emission Spectra; Extraterrestrial Radiation; Fluorescence; Forbidden Transitions; Optical Resonance; Red Shift; Astronomy; Quasars:Line Identifications full text sources ADS |

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