A measure of cosmological distance using the civ Baldwin effect in quasars by L. Huang et al. on Monday 21 November

We use the anticorrelation between the equivalent width (EW) of the

C\,\textsc{iv} 1549 {\AA} emission line and the continuum luminosity in the

quasars rest frame (Baldwin effect) to measure their luminosity distance as

well as estimate cosmological parameters. We obtain a sample of 523 Type I

quasars with the UV/optical spectra and EW (C\,\textsc{iv}) measurements in the

redshift range of $2.3< z< 7.1$ including 38 objects at $5 < z < 7.1$, which

can be used to investigate the C\,\textsc{iv} Baldwin effect and determine

cosmological luminosity distance. The relation $EW(C\,\textsc{iv}) \propto

{(\lambda {L_\lambda })^\gamma }$ can be applied to check the inverse

correlation between the C\,\textsc{iv} EW and ${L_\lambda }$ of quasars and

give their distance. The data suggest that the EW of C\,\textsc{iv} is

inversely correlated with continuum monochromatic luminosities. On the other

hand, we also consider dividing the Type I quasars sample into various redshift

bins, which can be used to check if the C\,\textsc{iv} EW-luminosity relation

depends on the redshift. Finally, we apply a combination of Type I quasars and

SNIa Pantheon to test the property of dark energy concerning whether or not its

density deviates from the constant, and give the statistical results.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2207.09456v3