CAOSP abstracts, Volume: 50, No.: 1, year: 2020

Abstract: Quasars accreting matter at very high rates (known as extreme Population A [xA]) may provide a new class of distance indicators covering cosmic epochs from present day up to less than 1 Gyr from the Big Bang. We report on the developments of a method that is based on ``virial luminosity'' estimates from measurements of emission line widths of xA quasars. The approach is conceptually equivalent to the virial estimates based on early and late type galaxies. The main issues related to the cosmological application of luminosity estimates from xA quasar line widths are the identification of proper emission lines whose broadening is predominantly virial over a wide range of luminosity, and the assessment of the effect of the emitting region orientation with respect to the line of sight. We report on recent developments concerning the use of the AlIIIλ 1860 intermediate ionisation line and of the Hydrogen Balmer line Hβ as ``virial broadening estimators.''

Full text version of this article in PDF.

Back to:
CAOSP Vol. 50 No. 1 index
CAOSP archive main index
CAOSP main page
Astronomical Institute home page
Valid XHTML 1.0! Valid CSS!

Last update: January 15, 2020