Low-ionization outflows in high Eddington ratio quasars
Por:
Marziani P., Sulentic J.W., Plauchu-Frayn I., Del Olmo A.
Publicada:
1 ene 2013
Resumen:
The broad Mg II ?2800 doublet has been frequently studied in connection with its potentially important role as a virial estimator of black hole mass in high-redshift quasars. An important task, therefore, is the identification of any line components that are likely related to broadening by non-virial motions. High signal-to-noise median composite spectra (binned in the "four-dimensional eigenvector 1" context of Sulentic et al.) were constructed for the brightest 680 Sloan Digital Sky Survey Data Release 7 quasars in the 0.4 ? z ? 0.75 range where both Mg II ?2800 and H? are recorded in the same spectra. Composite spectra representing 90% of the quasars confirm previous findings that FWHM(Mg II ?2800) is about 20% narrower than FWHM(H?). The situation is clearly different for the most extreme (Population A) sources, which are the highest Eddington radiators in the sample. In the median spectra of these sources, FWHM Mg II ?2800 is equal to or greater than FWHM(H?) and shows a significant blueshift relative to H?. We interpret the Mg II ?2800 blueshift as the signature of a radiation-driven wind or outflow in the highest accreting quasars. In this interpretation, the Mg II ?2800 line width - affected by blueshifted emission - is unsuitable for virial mass estimation in ?10% of quasars. © 2013. The American Astronomical Society. All rights reserved.
Filiaciones:
Marziani P.:
Instituto de Astrofisica de Andalucía, CSIC, E-18008 Granada, Spain
INAF, Astronomical Observatory of Padova, Padova, Italy
Sulentic J.W.:
Instituto de Astrofisica de Andalucía, CSIC, E-18008 Granada, Spain
Plauchu-Frayn I.:
Instituto de Astrofisica de Andalucía, CSIC, E-18008 Granada, Spain
Del Olmo A.:
Instituto de Astrofisica de Andalucía, CSIC, E-18008 Granada, Spain
|