An expanded M_bh-sigma diagram, and a new calibration of active galactic nuclei masses

Understand

[Abridged] We present an updated and improved M_bh-sigma diagram containing 64 galaxies for which M_bh measurements (not just upper limits) are available.

• Due to new and increased black hole masses at the high-mass end, and a better representation of barred galaxies at the low-mass end, the "classical" (all morphological type) M_bh-sigma relation for predicting black hole masses is log(M_bh/M_Sun) = (5.13+/-0.34)log[sigma/200] + (8.13+/-0.05), with an rms scatter of 0.43 dex.
• Modifying the regression analysis to correct for a hitherto over-looked sample bias in which black holes with masses <10^6 M_Sun are not (yet) detectable, the relation steepens further to give log(M_bh/M_Sun) = (5.95+/-0.44)log[sigma/200] + (8.15+/-0.06).
• We have also updated the &#34;barless&#34; and &#34;elliptical-only&#34; M_bh-sigma relations introduced by Graham and Hu in 2008 due to the offset nature of barred/disc galaxies.