Statistics of QSO broad emission-line profiles. 2: The C IV wavelength 1549, C III) wavelength 1909, and MG II wavelength 2798 lines

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view Abstract Citations (113) References (47) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Statistics of QSO Broad Emission-Line Profiles. II. The C IV lambda 1549, C iii] lambda 1909, and MG II lambda 2798 Lines Brotherton, M. S. ; Wills, Beverley J. ; Steidel, Charles C. ; Sargent, Wallace L. W. Abstract We present the results of a statistical investigation of broad emission-line profiles in a sample of 85 intermediate redshift QSOs (primarily 0.9 <= z <= 2.2), split about equally between radio-loud and radio-quiet objects. These emission lines, from the spectra of Steidel & Sargent's Mg II λ2798 absorption line survey, are reanalyzed in light of new results involving correlations with line width. Some new strong trends are found as line width (FWHM) increases: the ratio of line peak to continuum intensity decreases for C III] λ1909, the intensity ratio C III] λ1909/C IV λ1549 increases, the intensity ratio C III] λ1909/Mg II λ2798 decreases, and the peaks of C III] λ1909 and C IV λ1549 become increasingly blueshifted relative to the Mg II λ2798 peak. We present strong, clear differences between the broad emission-line spectra of radio-loud and radio-quiet QSOs. Radio-quiet objects have broader C III] λ1909 and C IV λ1549 lines than radio-loud objects, but the distributions of Mg II FWHMs do not differ significantly. The average ratio <FWHM_C III]_/FWHM_Mg II_> = 1.59 +/- 0.08 and <FWHM_C IV_/FWHM_Mg II_> = 1.35 +/- 0.09 for radio-quiet objects, but both are consistent with unity (+/-0.07) for radio-loud objects. The average ratio <FWHM_C III]_/FWHM_C IV_> = 1.20 +/- 0.05 for both radio-loud and radio-quiet objects. We interpret these results in terms of the two-component profile that we presented in Paper I: a narrow core (FWHM ~2000 km s^-1^) and a broad base (FWHM ~7000 km s^-1^) blueshifted by ~1000 km s^-1^. The core-to- base ratio determines the FWHM, asymmetry, and line shift. In general, radio-loud objects tend to have larger core-to-base ratios than radio- quiet objects. This scheme reproduces the observed correlations and most C IV λ1549 and C III] λ1909 profiles reasonably well, although the broadest C III] lines (FWHM_C III}_ > 7000 km s^-1^, typically radio-quiet objects) require either a base component with a blueshift that increases with line width, or a third extremely broad component with a very large blueshift. Publication: The Astrophysical Journal Pub Date: March 1994 DOI: 10.1086/173794 Bibcode: 1994ApJ...423..131B Keywords: Carbon; Emission Spectra; Line Spectra; Magnesium; Quasars; Radio Galaxies; Kinematics; Radio Emission; Red Shift; Spectral Line Width; Astrophysics; LINE: PROFILES; GALAXIES: QUASARS: GENERAL; GALAXIES: QUASARS: EMISSION LINES; RADIO CONTINUUM: GALAXIES full text sources ADS | data products SIMBAD (85) NED (85) Related Materials (1) Part 1: 1993ApJ...415..563W