The correlation of black hole mass with metallicity index of host spheroid

We investigate the correlation between the mass of the supermassive black holes (SMBHs) and metal abundance, using existing data sets. The SMBH mass M_bh is well correlated with integrated stellar feature of Mgb. For 28 galaxies, the best-fitting M_bh-Mgb relation has a small scatter, which is an equivalent level with other well-known relation, such as a correlation between the stellar velocity dispersion and the mass. An averaged iron index <Fe> also positively correlates with M_bh, but the best-fitting M_bh-<Fe> relation has a larger scatter. The difference comes from the synthesis and evolution mechanisms, and may be important for the SMBH and star formation history in the host spheroid.