THE SUPERMASSIVE BLACK HOLE MASS - SÉRSIC INDEX (AND OTHER) RELATION(S) FOR 
BULGES AND ELLIPTICAL GALAXIES

Giulia Savorgnan (CAS - Swinburne University of Technology)

Authors: Giulia Savorgnan and Alister W. Graham

Scaling relations between supermassive black hole (SMBH) mass, MBH, and various 
host spheroid properties are a powerful tool for studying galaxy-(black hole) 
coevolution. Furthermore, these relations enable us to predict the masses of 
SMBHs in other galaxies, and to measure the SMBH mass function and quantify the 
SMBH space density in our local universe. Graham & Driver (2007) presented 
evidence for a strong correlation between MBH and the central light 
concentration of the host bulge, quantified by the Sérsic index n. The MBH - n 
relation might be one of the simplest and strongest black hole mass scaling 
relations, requiring only uncalibrated galaxy images. However, the recent 
literature has failed to recover a strong MBH - n relation. Working with the 
authors of those works, we have successfully recovered the useful MBH - n 
relation. Moreover, we have explored for potential substructure in the MBH - n 
diagram based on galaxy morphology (elliptical or disc) and the nature of the 
central light profile (Sérsic or core-Sérsic). Future work will focus on 
accurately modelling the bulge/disc structure of ~80 local galaxies with direct 
MBH values and a re-investigation of all the black hole mass scaling relations.