The Origin and Evolution of C iv Baldwin Effect in QSOs from the Sloan Digital Sky Survey
نویسندگان
چکیده
Using a large sample of 26623 quasars with redshifts in the range 1.5 ≤ z ≤ 5.1 with C iv λ1549 Å emission line in Fifth Data Release of the Sloan Digital Sky Survey (SDSS), we investigate the cosmological evolution of the Baldwin Effect, i.e. the relation between the equivalent width (EW) of the C iv emission line and continuum luminosity. We confirm the earlier result that there exists a strong correlation between the C iv EW and the continuum luminosity, and we find that, up to z ≈ 5, the slope of the Baldwin Effect seems to have no effect of cosmological evolution. A sub-sample of 13960 quasars with broad C iv λ1549 Å emission line from SDSS is used to explore the origin of the Baldwin Effect. We find that C iv EW have a strong correlation with the mass of supermassive black hole (SMBH), and a weak correlation with the Eddington ratio, LBol/LEdd. This suggests that the SMBH mass is probably the primary drive for the Baldwin Effect.
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The Sloan Digital Sky Survey is an ambitious, multi-institutional project to create a huge digital imaging and spectroscopic data bank of 25% of the celestial sphere, approximately 10,000 deg2 centred on the north galactic polar cap. The photometric atlas will be in 5 specially-chosen colours, covering the π ster of the Survey area to a limiting magnitude of r∼23.1, on 0 . 4 pixels, resulting i...
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