Quasar Black Hole Mass Estimates from High-Ionization Lines: Breaking a Taboo?

Paola Marziani, Ascensión Olmo, Mary Martínez-Aldama, Deborah Dultzin, Alenka Negrete, Edi Bon, Natasa Bon, Mauro D'Onofrio
2017 Atoms  
Can high ionization lines such as CIVλ1549 provide useful virial broadening estimators for computing the mass of the supermassive black holes that power the quasar phenomenon? The question has been dismissed by several workers as a rhetorical one because blue-shifted, non-virial emission associated with gas outflows is often prominent in CIVλ1549 line profiles. In this contribution, we first summarize the evidence suggesting that the FWHM of low-ionization lines like Hβ and MgIIλ2800 provide
more » ... gIIλ2800 provide reliable virial broadening estimators over a broad range of luminosity. We confirm that the line widths of CIVλ1549 is not immediately offering a virial broadening estimator equivalent to the width of low-ionization lines. However, capitalizing on the results of Coatman et al. (2016) and Sulentic et al. (2017) , we suggest a correction to FWHM CIVλ1549 for Eddington ratio and luminosity effects that, however, remains cumbersome to apply in practice. Intermediate ionization lines (IP ∼ 20-30 eV; AlIIIλ1860 and SiIII]λ1892) may provide a better virial broadening estimator for high redshift quasars, but larger samples are needed to assess their reliability. Ultimately, they may be associated with the broad-line region radius estimated from the photoionization method introduced by Negrete et al. (2013) to obtain black hole mass estimates independent from scaling laws.
doi:10.3390/atoms5030033 fatcat:yhpysxz7knf2fhoxwbghbkco3i