The effect of bars on the MaEuro¢-σe relation: offset, scatter and residuals correlations

We analyse a set of collisionless disc galaxy simulations to study the consequences of bar formation and evolution on the M-aEuro cent-sigma(e) relation of supermassive black holes (SMBHs). The redistribution of angular momentum driven by bars leads to a mass increase within the central region, raising the velocity dispersion of the bulge, sigma(e), on average by similar to 12 per cent and as much as similar to 20 per cent. If a disc galaxy with an SMBH satisfying the M-aEuro cent-sigma(e) relation forms a bar, and the SMBH does not grow in the process, then the increase in sigma(e) moves the galaxy off the M-aEuro cent-sigma(e) relation. We explore various effects that can affect this result including contamination from the disc and anisotropy. The displacement from the M-aEuro cent-sigma(e) relation for individual model barred galaxies correlates with both the bulge-to-total stellar mass ratio, M(B)/M(B + D), and the 2D anisotropy, beta(I center dot)(B + D), both measured within the effective radius of the bulge. Overall, this process leads to an M-aEuro cent-sigma(e) for barred galaxies offset from that of unbarred galaxies, as well as an increase in its scatter. We assemble samples of observed unbarred and barred galaxies with classical bulges and find tentative hints of an offset between the two consistent with the predicted. Including all barred galaxies, rather than just those with a classical bulge, leads to a significantly larger offset, which is mostly driven by the significantly larger offset of pseudo bulges.