The first measurement of the Mg II line delay in a quasar at redshift ∼1

Bożena Czerny, Justyna Sredzinska, Jan Kotlarz, Andrzej Udalski, Swayamtrupta Panda and Conor Wildy

Since 4 years we perform reverberation monitoring of three quasars with the Southern African Large Telescope (SALT). Finally, we are able to give the preliminary estimate of the time delay for one of the quasars, CTS C30.10. The time delay of Mg II line with respect with continuum variation is 1050 days, longer than the expected value. This is in contradiction to recent claims that the sources with relatively high Eddington ratio show in general much shorter time delays than expected. This measurement has consequences for the black hole mass determination in high redshift sources, as it extends the scaling relation between the mass, line width and the monochromatic luminosity obtained for nearby AGN. This also opens the way to apply quasars for distance determination and to constrain the expansion rate of the Universe and the character of the dark energy.

Proceedings of the Polish Astronomical Society, vol. 7, 267-269 (2018)

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