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arXiv · 2307.02962

No redshift evolution in the rest-frame UV emission line properties of quasars from z=1.5 to z=4.0

Matthew Stepney·Manda Banerji·Paul C. Hewett·Matthew J. Temple·Amy L. Rankine·James H. Matthews·Gordon T. Richards
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Abstract

We analyse the rest-frame UV spectra of 2,531 high-redshift (3.5 3.5 using a cross-correlation algorithm that employs high signal-to-noise template spectra spanning the full range in UV emission line properties. We then quantify the evolution of C IV and He II emission line properties with redshift. The increase in C IV blueshifts with cosmological redshift can be fully explained by the higher luminosities of quasars observed at high redshifts. We recover broadly similar trends between the He II EW and C IV blueshift at both 1.5 0.2 and Mbh > 10^9 Mo for the entire 1.5 6 are on average less massive and have higher Eddington-scaled accretion rates than their luminosity-matched counterparts at 1.5<z<4.0, which could explain the observed evolution in their UV line properties.

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Matthew Stepney, Manda Banerji, Paul C. Hewett, Matthew J. Temple, Amy L. Rankine, James H. Matthews, Gordon T. Richards. 2023-07-06. No redshift evolution in the rest-frame UV emission line properties of quasars from z=1.5 to z=4.0. https://doi.org/10.1093/mnras%2Fstad2060

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